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MATLAB - Science topic

MATLAB (matrix laboratory) is a numerical computing environment and fourth-generation programming language. Developed by MathWorks, MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages, including C, C++, Java, and Fortran.
Questions related to MATLAB
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Dear All,
  • I have experienced quite long times for reading data from a GDX-file.
  • The particular thing with the data is that it consists of long vectors – representing (12 time steps a day)*(7 days a week)*(52 weeks a year (approximation, yes))*(32 years) = 139776 time steps.
  • But the data itself is smaller than many GDX files I have worked with earlier.
  • Some examples of reading times of this data are 1300-3000 seconds using tic/toc in Matlab
  • Here are examples of code used to read the data:
tic
LoadDummy = struct('name','p_D','form','full','uels',{t.uels{1}});
ReadDummy = rgdx('gdxout.gdx',LoadDummy);
p_D = ReadDummy.val;
toc
tic
LoadDummy = struct('name','p_G','form','full','uels',{t.uels{1}});
ReadDummy = rgdx('gdxout.gdx',LoadDummy);
p_G = ReadDummy.val;
toc
tic
LoadDummy = struct('name','ProfitM','form','full','uels',{t.uels{1}});
ReadDummy = rgdx('gdxout.gdx',LoadDummy);
ProfitM = ReadDummy.val;
toc
  • Where
  1. LenghtTime = 139776
  2. t.uels = {guel('t',1:LengthTime)};
  3. guel = @(string,number) strcat(string,strsplit(num2str(number))); %function that creates the indexes names
  • I also attach the GDX file in case someone wants to give it a try
  • Is this normal do you think or is it anything that I could do to improve the reading times of the GAMS results into Matlab?
  • Would it be faster with CSV, SKV or similar?
  • If anything is unclear or more information is needed – don’t hesitate to ask me!
  • I read locally from C:, the computer is (unfortunately) an i5, and there is 16 GB RAM.
Best Regards,
Lars
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No this is about reading data.
I have a discussion with the GAMS support, and they seem to be as surprised as me.
Some preliminary study showed that the reading time increased with the power of four for larger data sets.
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I am looking for a package (C, C++, C#, etc) that can numerically compute the Inverse Laplace Transform (ILT) of any given function. I know that MatLab and Octave perform symbolic inversion, but there code cannot be easily ported to general purpose programming languages.
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This is definitely interesting. Thank you Sourangshu.
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I need to prepare R correlation coefficient for all targets that I have, but the output of NN tools only gives me the overal R. How can I prepare it? If any one knows I am so appreciate to share it with me.
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R value is coefficient of correlation. It shows how well your predicted outputs are matching with real outputs so your trained network is good if R closed to 1.
0.2 and 0.3 are showing bad network. you should train your network with other no of hidden layers, other algorithms or you check the input parameter once.
Hope it helps,
Shreyas
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Hi,
How to generate "N" feasible solutions of an LP where all variables are in the range [0,1] , using cplex or matlab ?
Any help will be appreciated,
Thanks in advance.
Z.Mezali
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Hi,
In my opinion, Newton's method can find a root for a univariate polynomial, while the Weierstrass's method can approximate all roots of this one.
Therefore, I think that you can apply the above idea to get all feasible solutions.
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These methods are used to solve linear system of equations.
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The width of each triangular pulse should be 20 microseconds or 50kHz and height should vary between 0 and 1.
And I have to divide each triangular pulse into 100 divisions and each division should be 0.2 micro seconds.
Then, I have to plot it into t = 1:1: 20000. If it is not possible, another way is fine.
Please help me with this. Thank You
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Hi,
I need to generate broadband random vibration using Matlab to run shaker using NI output.
Example, random broadband vibration at 0.4 r.m.s (1-20Hz) which running for 60seconds. how to create the script for this case in Matlab?
this is the guideline that i found in documentation , but this is not for case as mentioned.
n = S.Rate;
outputSignal = sin(linspace(0,2*pi*10,n)');
queueOutputData(s,outputSignal) % Queuing the data for output
startForeground(s);
thanks for any helps and guide
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Muhammad Ali Tajim Md. Niamat Ullah Akhund Thanks for the links and very helpful sources.
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Question is related to Massive MIMO OFDM system Channel estimation by Least squares approach for ZF and MMSE Detectors
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The best and only way is to request the First author of the paper you have attached. See also https://au.mathworks.com/matlabcentral/fileexchange/67156-ofdm-channel-estimation-in-matlab?s_cid=ME_prod_FX
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I want to extract Hop count, link utilization and random placement from Topology zoo data set, and I have no idea how to do that. additionally, i'm going to use that criteria for SDN controller placement problems in matlab.
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This discussion is still open?
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Delft 3D-Flow produces NEFIS compliant history and map file output (*.dat files). The view capability of Delft 3D 's post processor is good but not as advanced as the specialized (scientific) visualization software like ParaView or VisIt. I want to view Delft 3D output in in ParaView but ParaView cannot open Delft 3D files directly.
One possible way is to convert Delft 3D output files to NetCDF (*.nc) files and then view it in ParaView as it can open *.nc files. I have even found a Matlab (see this https://oss.deltares.nl/web/delft3d/general/-/message_boards/view_message/1379779 and https://svn.oss.deltares.nl/repos/openearthtools/trunk/matlab/applications/delft3d/vs_trim2nc.m ) script as well to do the job however it failed with an error message ( Undefined function or variable 'filenameext' )
I do not know any other possible way to do the job. If someone would guide, suggest any other possibility or just comment, it will be highly appreciated.
Thanks and Regards
Ahmed
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I think you could find more clarifications of your question in the 15 Delft3d webinar "15.?'Efficient pre- and post-processing in Delft3D using the OpenEarthTools' " .
Sincerly.
Hamza
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I'm a Mtech student and want to get involved in #angiogenesis field. And now, I want to learn a programing language that suits my field most. Please can anyone suggest me which language is best for my field??
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In the scientific community, as you know, Matlab and Python are preferred. Matlab is well-suited for scientific computing, but it is expensive and generally quite narrowly focused. In essence, this is a mathematical package, not a complete programming language. Python is free. Also, Python is a full-fledged programming language and a very large number of libraries have been written for it, sharpened for scientific tasks. Modeling, graphics, whatever. It is also well compatible with C and C ++ languages, which is useful for writing high-speed programs. So I recommend Python.
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My mathematical model is giving results on single variable entry. I have a total of 250 variables and need to evaluate the results from the same model. Instead of putting values one by one, is it possible to import the 250 variables data in bulk and at the end get the separate results through one single model?
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Hello
I have a system of linear equations composed of 11 equations and 11 variables, I solved it through Excel and MATLAB in the form of AX=B.
While the matrix A , matrix B and the inverse of matrix A are identical in the two programs, the solution vector X differs ( three of the vector elements are different).
Why such thing would happen? and which of them are correct ?
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You're welcome Wael Badr.
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I want to model lazy eight maneuver by matlab simulink or AI.
what shall I do???
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Matlab code for State Space analysis of Doubly Fed Induction Generator?
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Dear Tej Enosh
Matlab code of Wind Turbine Doubly-Fed Induction Generator (Phasor Type) is explaining in this link:
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Currently working on a lunar rover for a university masters project, my colleagues have successfully developed a code that considers not only where the solar panels are situated in relation to each other due to the rover shape (1 on each side ) but also the long and lat for the position on the moon.
I reach out to people in the relevant field for a helping hand in developing this code as it fails to include the sun elevation, although it remains low when at the poles which is the likely landing site it will change the power output of the panels especially when terrain is also considered.
Advice/Tips/Suggestions fully welcome!!
Thank you.
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Dear colleagues
I am looking for the electrical specifications of a 10W PV module for simulation use on Matlab ?
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Dear Abdelhakim,
if you have the datasheet values, then you can use an iterative method like Newton-Raphson to extract the parameters of the PV module. For the single-diode model, the photovoltaic current, the saturation current of the diode, the ideality factor, the series, and the shunt resistances.
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Traffic offloading from Macro cell to pico/femto/micro. I just need a starting MATLAB code for designing 2-tier heterogeneous network.
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The following links for designing a 2-tier heterogeneous network:
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Hi.
How can I use matlab to deconvolute spectra (I'm using matlab r2015a)? For example, I combined the molecules A and B which will produce the molecule C, so my final composition consists of A, B, and C. I know the spectral features of both pure A and pure B, so I want to deconvolute the spectra of the combined A and B (which also have C) to determine the spectra of C. Thank you.
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In Sugeno Fuzzy Inference System Model Output membership function is either linear or constant in the following form
z = ax + by + c
Here a, b and c are different for each rule ( as per my understanding)
Now how to find the a, b, c values for each rule, manually or with any algorithm ( not from Matlab) ?
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Lets consider a mtrix AA(400*400*400) and another matrix BB(100*100). Every element from AA has to multiply with all the elements of BB and sum up the result which will produce a single element. Finally the resultant matrix RR will be of same size as of AA.
RR(1,1,1) = sum(sum(A(1,1,1).*BB); % as for example
Using for loop in matlab it can easily be solved. Is there any efficient way to solve it without using any loop?
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this instruction perform your requirement
rr=a*sum(b(:))
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The formula to calculate the number of coefficients mentioned on fist paragraph of page 7 in the paper "Deep Scattering Spectrum" does not work for me. I'm using layer 2 with Q = [6 1], and window size of 512 samples. As per the formula, number of coefficients in the first layer should be about Q1*log2N = 6*log2512 = 54. Similarly for second layer, it should be Q1*Q2*(log2N)^2/2 = 6*1*9*9/2 = 243. Whereas, with this setting MATLAB gives 94 features.
Can any one please clarify as why the answer of mine is different from MATLAB.
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You can check the tutorial on the MatLab website
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Recently, I came across this situation wherein the value of Rsquare found to be 1 with the lower RMSE. What does it mean (in the practical sense)? Will it have any different consequences than normal regression model's outcomes? Please share your expert opinions and suggestions.
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Hi @Shaktiyavesh Nandan Pratap Singh
In regression-based models, the RMSE criterion means the square root of the mean square error. The lower the value of this criterion, the better the situation.
This type of minimization is very common in data mining and classification. In it, we calculate the total errors of each point relative to the constructed model, and this in itself is a measure of the goodness of the model constructed by the algorithm.
Good luck
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Is there a Reliable Simulink-based model that can be used to generate the Lyapunov exponents, the bifurcation diagram, and the Poincaré section for continuous-time chaotic systems, at least the famous third/fourth order ones.
If no, what is the most recent MATLAB code that can do that, with the best accuracy.
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I have used the following tool box for computing Lyapunov exponents.
The GUI is also available and the source code can be easily modified. You can also code it yourself as I believe it can be done easily.
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Does anyone know how to change the wiedemann parameters in PTV Vissim from matlab?
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The purpose of this study is to identify a new design concept in Internet of Things by exploring new patterns in which different technologies, devices and protocols can integrate with one another with the aim of defining the due processes of data acquisition, aggregation and transmission from the perspective of Field Programmable Gate Arrays (FPGAs), without inherently presenting major constraints to the designer.
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Hi every one. Anyone pls suggest me what is the best segmentation algorithm for segmenting leaf region from the real field images. Consider that real field images contains too many unwanted objects like other leaf images, branches, human parts ( like fingers, shoes) etc. And also kindly provide me MATLAB code for this if possible. Thank you.
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Dear all
Please check the free document at the following link :
Article Plant Leaves Image Segmentation Techniques: A Review
Regards
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I am working on a closed-loop system which has a PI controller. I have made a Simulink environment for the overall scenario but now I want to optimize the coefficients of the PI controller through an optimization Algorithm which will be having a Matlab code. So, can anybody help in this regard?
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this simple program to tuning PID controller based PSO
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Does anyone have MATLAB code for training CNN with optimization?
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I have designed a synchronous buck-boost converter for the supercapacitor. I've set the rated voltage to 32v and the number of series capacitors to 1. However, on the input side, the voltage displayed is 10.3v. The voltage doesn't add up either when I change the number of series capacitors. Where am I going wrong?
The model of Supercapacitor chosen is from electrical drives.
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I think you must explain your problem more clearly.
If I understood you you have a source composed of supercapacitors connected in series. The open circuit avolated of the one capacitor is eqaul to its rated voltage of 2.7V. You have 12 capacitors connected in series with a series resistance of one capacitor= 8.7 10^-3 Ohm.So the total resistance will be 12x8.7 10^-3.
About .08 ohm. So, there is about 4 V drop on this resistance and the current amounts to approximatively to 4/.08= 50 A.
So, you have to measure the current withdrawn from the capacitor bank to check that the drop is the voltage is due to the current flowing in the series resistances.
Please give us feedback!
Best wishes
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Dear all, I am trying to implement pose normalization for face images using piece-wise affine warping. I am using delaunayTriangulation to construct face mesh based on detected 68 landmarks for two images: one with frontal face and the other with non-frontal face. The resulted meshes do not have the same number of triangles and also have triangles that are different in direction and location.
Could anyone help please? Thanks.
------------------------------------------------------------
% Construct mesh for frontal face image
filename1 = '0409';
img1 = imread([filename1 '.bmp']);
figure, imshow(img1); hold on;
pts1 = load([filename1 '.mat']); % Load 68-landmarks
DT1 = delaunayTriangulation(pts1.pts);
triplot(DT1,'cyan');
% Construct mesh for non-frontal face image
filename2 = '0411';
img2 = imread([filename2 '.bmp']);
figure, imshow(img2); hold on;
pts2 = load([filename2 '.mat']); % Load 68-landmarks
DT2 = delaunayTriangulation(pts2.pts);
triplot(DT2,'cyan');
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I want to implement below mentioned look up table in matlab simulink but i got error mentioning that ," Unable to perform assignment because the size of the left side is 2-by-3 and the size of the right side is 2-by-5." how to solve this error?
a(:,:,1) =[3 39 0 44 28;35 19 63 24 60];
a(:,:,2) =[35 19 63 30 12;51 33 0 44 28];
a(:,:,3) =[51 33 0 13 14;49 50 63 30 12];
a(:,:,4) =[49 50 63 6 15;48 57 0 13 14];
a(:,:,5) =[48 57 0 11 7;52 56 63 6 15];
a(:,:,6) =[56 52 63 39 3;60 24 0 11 7];
a(:,:,7) =[60 24 0 19 35;28 44 63 39 3];
a(:,:,8) =[28 44 63 33 51;12 30 0 19 35];
a(:,:,9) =[12 30 0 50 49;14 13 63 33 51];
a(:,:,10) =[14 13 63 57 48;15 6 0 50 49];
a(:,:,11) =[15 6 0 52 56;7 11 63 57 48];
a(:,:,12) =[7 11 63 24 60;3 39 0 52 56];
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I don't see any problem, cause i executed it
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What are the programs written in matlab and pyton to describe the dynamics of a fiber laser and the numerical calculation of intensity and population based on speed kinetic differential equations?
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Abbas Miry, thank you for answer.
I already knew these links in the mathwork.com you indicated.
But I have a more difficult task: studying the dynamics of a fiber laser in transition mode. That is, I have already modeled the differential equations for the fiber laser in matlab. I used a system of three differential equations for population, intensity and pumping, respectively, as the starting points. This system of equations takes into account both the temporal and distribution dependencies of these parameters on the space or length of the optical fiber.
In modeling, using Runge Kutt's 2 and 4 order method, I encountered that my program was time consuming.
In the future, I want to add a block of spectral fourier analysis to the program. And then the calculation time will be further increased.
I would like to ask, if anyone was involved in such modeling, what methods should be used to reduce billing time.
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I would like to automate some processes within MATLAB, some data need to be inserted from PSS/E software. Is there a Matlab Command to do so?
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What is the difference between using Matlab and Python in the field of deep learning?
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Advantages of Matlab
MatLab has a large number of committed users which include many universities and a few companies who have the budget to buy a license for the program. Even though it is used in many universities, Matlab is easy for beginners who are just starting to learn about programming language because the package, when purchased, includes all that you will need.
When using Python you are required to install extra packages. One part of MatLab is a product called Simulink, which is a core part of the MatLab package for which there does not yet exist a good alternative in other programming languages.
Disadvantages of Matlab
Disadvantage is its cost of License. Its very costly user has to buy each and every module and pay for it. Disadvantage is during cross compiling or converting Matlab to other language code is very difficult. Its very difficult or requires deep devel Matlab knowledge to deal with all errors.
Matlab is not suggested to make any product. Because, Matlab doesn’t create application deployment like task (like setup files and other executable which copies during installation).
Advantages of Python
The Python language has diversified application in the software development companies such as in gaming, web frameworks and applications, language development, prototyping, graphic design applications, etc.
– User Friendly and Easy to learn – Cross platform supported – Vast community support – Very powerful – Open source
– Python Packages Index ( PyPI ) – hosts thousands of third-party modules for python.
Applications
  • Web and Internet Development
  • Database Access
  • Desktops GUIs
  • Scientific and Numeric
  • Education
  • Network Programming
  • Software and Game Development
This provides the language a higher plethora over other programming languages used in the industry. Some of its advantages in details are-
Extensive Support Libraries It provides large standard libraries that include the areas like string operations, Internet, web service tools, operating system interfaces and protocols. Most of the highly used programming tasks are already scripted into it that limits the length of the codes to be written in Python.
Integration Feature Python integrates the Enterprise Application Integration that makes it easy to develop Web services by invoking COM or CORBA components. It has powerful control capabilities as it calls directly through C, C++ or Java via Jython. Python also processes XML and other markup languages as it can run on all modern operating systems through same byte code.
Improved Programmer’s Productivity The language has extensive support libraries and clean object-oriented designs that increase two to ten fold of programmer’s productivity while using the languages like Java, VB, Perl, C, C++ and C#.
Productivity With its strong process integration features, unit testing framework and enhanced control capabilities contribute towards the increased speed for most applications and productivity of applications. It is a great option for building scalable multi-protocol network applications.
Disadvantages of Python
Python has varied advantageous features, and programmers prefer this language to other programming languages because it is easy to learn and code too.
However, this language has still not made its place in some computing arenas that includes Enterprise Development Shops. Therefore, this language may not solve some of the enterprise solutions, and limitations include-
Difficulty in Using Other Languages The Python lovers become so accustomed to its features and its extensive libraries, so they face problem in learning or working on other programming languages. Python experts may see the declaring of cast “values” or variable “types”, syntactic requirements of adding curly braces or semi colons as an onerous task.
Weak in Mobile Computing Python has made its presence on many desktop and server platforms, but it is seen as a weak language for mobile computing. This is the reason very few mobile applications are built in it like Carbonnelle.
Gets Slow in Speed Python executes with the help of an interpreter instead of the compiler, which causes it to slow down because compilation and execution help it to work normally. On the other hand, it can be seen that it is fast for many web applications too.
Run-time Errors The Python language is dynamically typed so it has many design restrictions that are reported by some Python developers. It is even seen that it requires more testing time, and the errors show up when the applications are finally run.
Underdeveloped Database Access Layers As compared to the popular technologies like JDBC and ODBC, the Python’s database access layer is found to be bit underdeveloped and primitive. However, it cannot be applied in the enterprises that need smooth interaction of complex legacy data.
Let’s consist a small combination of them – following can be incredibly useful –
MATLAB
– Invaluable for signal processing – Incredibly broad array of useful libraries – Simplest and most concise language for anything involving matrix operations – Works very well for anything that is simply represented as a numeric feature matrix – Huge pain to use for anything that isn’t simply represented as a numeric feature matrix – Lacking a good open source ecosyste
Python
– Very fragmented but comprehensive scientific computing stack – Pandas, scikit.learn, numpy, scipy, ipython, & matplotlib are my most-used scientific computing libraries – IPython notebook makes a nice interactive data analysis tool – All the benefits of a general purpose programming language – Unfortunately slow if you don’t drop into C – Some of the scientific computing stack is still stuck in Python 2.7 – Very good for problems that don’t come as a simple feature matrix, between tools like pandas and nltk – Incredible open source ecosystem
Python is most popular language in the AI field.
Why ? Because –
Python comes with a huge amount of libraries. Many of the libraries are for Artificial Intelligence and Machine Learning. Some of the libraries are Tensorflow (which is high-level neural network library), scikit-learn (for data mining, data analysis and machine learning), pylearn2 (more flexible than scikit-learn), etc. The list keeps going and never ends.
For other languages, students and researchers need to get to know the language before getting into ML or AI with that language. This is not the case with python. Even a programmer with vert basic knowledge can easily handle python.
Apart from that, the time someone spends on writing and debugging code in python is way less when compared to C, C++ or Java. This is exactly the students of AI and ML wants. They don’t want to spend time on debugging the code for syntax errors, they want to spend more time on their algorithms and heuristics related to AI and ML. Not just the libraries but their tutorials, handling of interfaces are easily available online. People build their own libraries and upload them on GitHub or elsewhere to be used by others
Python has a solid claim to being the fastest growing major programming language. Recommended to check ground breaking statistics on incredible growth of python and why is python growing so quickly from stack overflow.
Advantages of Python over Matlab
1. Python code is more compact and easier to read than Matlab code —- Unlike Matlab, which uses end statement to indicate the end of a block, Python determines block size based on indentation. —- Python uses square brackets for indexing and parentheses for functions and methods, whereas Matlab uses parentheses for both, making Matlab more difficult to differentiate and understand. —- Python’s better readability leads to fewer bugs and faster debugging.
2. While most programming languages, including Python, use zero-based indexing, Matlab uses one-based indexing making it more confusing for users to translate.
3. The object-oriented programming (OOP) in Python is simple flexibility while Matlab’s OOP scheme is complex and confusing
4. Python is free and open —- While Python is open source programming, much of Matlab is closed —- The developers of Python encourage users to input suggestions for the software, while the developers of Matlab offer no such interaction
5. There is no Matlab counterpart to Python’s import statement 6. Python offers a wider set of choices in graphics package and toolsets
In Steve Hanly’s research on the speed test between Python and MATLAB for vibration analysis
Utilization of Python
Python has been gaining momentum as being the programming language for novice users. Highly ranked Computer Science departments at MIT and UC Berkeley use Python to teach their novice programming language students. The three largest Massive Open Online Course (MOOC) providers (edX, Coursera andUdacity) all use Python as their programming language for their beginning courses in programming. A variety of professors in other disciplines now utilize the need for novice students to understand Python and its key features.
Conclusion
There is no such thing as a ‘best language for machine learning’
Popularity is not a good yardstick to use when selecting a programming language for machine learning and data science. There is no such thing as a ‘best language for machine learning’ and it all depends on what you want to build, where you’re coming from and why you got involved in machine learning.
In most cases developers port the language they were already using into machine learning, especially if they are to use it in projects adjacent to their previous work?—?such as engineering projects for C/C++ developers or web visualizations for JavaScript developers.
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Presently I am working on constructing a predictive model for random data set which is based on some Logarithmic Equation like Y=a1.log(x1)+a2. log(x2)+ a3.log(x3)+...+C alongwith some other linear equations.
While training the data with the robust regression model the outcomes are:R2=1, RMSE=0.00001. Is that possible? Or something missing? Please share your opinions on
How to construct a predictive model if the dataset is based on some logarithmic equation?
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Hi @Shaktiyavesh Nandan Pratap Singh
That's an interesting question,
I am studying this question and agreeing with my group.
I will share the result with you soon.
Good luck
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clear all
del_l=-2:0.001:3; %two cavities with nano paricle in first cavity and no mechanical resonator
for n=1:length(del_l);
del=del_l(n);
k1=4;
F2=100;
U2=9;
w1=6.61*10^5;
J=k1;
k11=2*pi*6*10^4; %0.25*10^6
k22=1*k11;
k1=k11/w1;
k2=k22/w1;
D1=1;
D2=1;
m11=3.94*10^-17; %3.25*10^-17; %(mass of nano oscillator )
m1=m11/w1;
r11=0.003; %(decay of nano oscillator )
r1=r11/w1;
KP1=k1+1i*(D1-del);
KP2=k1-1i*(D1+del);
KP3=-k2+1i*(D2-del);
KP4=-k2-1i*(D2+del);
F1=m1*(w1^2-1i*r1*del-del^2)*KP3*(J^2+KP2*KP4);
U1=m1*(w1^2-1i*r1*del-del^2)*(J^2+KP1*KP3)*(J^2+KP2*KP4);
Tr(n)=2*k1*((F1+F2)/(U1-U2));
T(n)=abs(1-2*k1*((F1+F2)/(U1-U2)))^2;
end
hold on
grid on
plot(del_l,T,'b')
These are arbitrary values.
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Please have a look at the new code......
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I would like to know if Aspen Plus can be linked with MATLAB or Python?
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I am looking into the permeation of gases through porous metallic sintered plates when different pressures are applied on either sides of the plate. Darcy's permeabilities and Forchheimer's constants of the plates are known. My aim is to predict the flow through such plates depending on the pressure differences.
I have found a model where the Darcy-Forchheimer-Equation is integrated into the Navier-Stokes-equations, and simple block meshing and finite volumes are very suitable for the prediction of throughput through the plates (at least in my opinion). However, the Darcy-Forchheimer-equation in Navier-Stokes is a velocity dependent source term and the experiments are quite similar to shock-tubes (High-Pressure on one side, low pressure on the other and inside the sintered plate as initial condition).
I wrote a simple simulation in Python which did not work. I think the reason for this is that energy conservation is broken because of the velocity dependence of the source term and the shock-type initial condition. Do you have any idea where I can find references / computer codes (Fortran, Matlab, Python) which would help me with my problem?
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Dear Akram Jassim Jawad,
thank you for sending me the paper. It is a very interesting approach for using the semi-implicit Crank-Nicholson-method on a Diffusion-Advection-Reaction/Absorption differential equation.
Unfortunately, this equation only works on porous materials at very low Reynolds-numbers. But thank you again.
BR
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I wanna apply parallel computing techniques to decrease the calibration time. Using the code below, I can calculate 10 sets for 11 parameters simultaneously using PARFOR loop but I cannot get the cost function value simultaneously for each set of parameters values during the calibration process using GA. Your helpful commands and suggestion are highly appreciated.
% GA Parameteres
MaxIt=20; % Maximum Number of Iterations
nPop=10; % Population Size
NoVar=11; % No. of parameters to be calibrated during
delete(gcp('nocreate')) % shut down previous parrel computing
parpool('local') % Activate parallel computing parfor
i=1:nPop
pop(i).Position=unifrnd(VarMin,VarMax,VarSize);
pop(i).Cost=CostFunction(pop(i).Position);
end
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If someone has any model of simulation in which power loss is calculated or anything helping material please suggest. I have it in code form but want to implement it on any distributed system in Simulink.
Thanks
Babar
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I am also interested to know as well would be great if you could share any materials you may have.
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Hi Everyone,
I want to know formula for Radiation Pattern (E Field and H Filed) of Rectangular Microstrip Antenna for Finite Ground Plan. I have already implemented Balanis Book and Microstip Antenna Handbook Formula in matlab , but not getting similar result.
I mean formula, and its radiation pattern given in book, not matching with my program result.
So if anyone implemented it ,kindly share with me or suggest me another good book so that i can implement in.
Thank you.
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You can look at this PDF of the rectangular patch antenna's formula and one design example for it!
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What is the easiest method to implement the GPC in Matlab?
After the development of the GPC algorithm I got the equation on the image being U(t) the control signal and y(t) the output signal and w(t) the reference signal which is known in advance as a sine wave signal, how can i implement this in Matlab? can i use a sine wave generator bloc and discretize it using a zoh bloc than i send it for a Matlab function which includes include the aforementioned equation.
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Thanks for your answer, it's really helpful, for the future reference i will generate it as .m code i think it's the most appropriate way.
Cordially
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I hope to know a difference between randomization, CLA, ILA, DWA using matlab.
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Dear;
for more information please check the following documents:
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Hello everyone, I am designing a 4WD differential robot that has to fit inside a 7" cube, and I am having trouble finding a DC motor with an encoder that is small enough to fit inside my robot. This is my conceptual chassis design, using 2" wheels from AndyMark, and the wheels are only 3.8 " apart so I am imagining that probably a wormgear motor is the best solution (since I can build upwards). Does anyone know of any good suppliers that make such small motors? The inner diameter of wheels is 8 mm but I will mostly make a conversion plate anyways so the shaft diameter of the motor is not important.
Thanks!
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@Alaa Ali your most welcome .
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I have been working on 3D FEM in Matlab. Done different verifications tests and have good match with Abaqus and analytical results for some cases, but for a 1/8 sphere, I am facing this issue.
The interior of 1/8 sphere has been pressurized. But, the displacement at the 3 edges are for some reason small. This cause Bulging at the Interior.
I have checked everything from Boundary condition to Formulation, but couldn't find any issue. Do you have experience with this? Can you please suggest why this is happening?
I have attached the result for Matlab and Abaqus here.
Thanks.
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Hi, thanks everyone, I solved the issue. This is due to the shear modulus used to generate Constitutive matrix was not in correct format.
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Hello,
I am trying to do some analysis on a large dataset with DEA.
Is there any free software out there that has a slack based Network DEA model (Tone, Tsutsui, 2009)?
It can be Python, Matlab, R or any other kind of software.
Thanks in advance :)
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Thank you Ashiq Mohd Ilyas I will try them out!
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Hello everyone.
I am looking for the grid points of grain boundaries(blue sections).Is there a way to aciheve them by image processing in Matlab?.
Thanks.
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I have a Simulink model and C code for a project. I need to cross verify by transforming c code to Simulink model. Can it be possible in Matlab or any other Source for the same.And too i tried S-function also, can I able to get BBang block, or any function block such as Addition, Subtraction etc, in s-function by transforming c code to simulink.
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Greetings
I need a MATLAB Code for blood vessels segmentation.
The link shows an example image from which vessels should be extracted
Thank You in Advance
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How much accuracy we can achieve in retinal blood vessel segmentation?
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hello dear @all! I have tried to plot Pd Vs SNR using adaptive threshold for simple energy detection and it came out as I wanted, but when I go to plot Pd Vs SNR using fixed(conventional) threshold I got an error says "Undefined function or variable 'Pf'." and I have defined Pf=0.01, but still matlab says I have not defined it. please help me. the formula am using for fixed threshold is thresh_c = (qfuncinv(Pf)./sqrt(N))+ 1;
thanks
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How have you solved this problem? Can you please help me out.
Thanks.
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I have tried to install SOSTOOLS in matlab 2016a while following the instructions detailed in the manual. However, I end up getting the error (shown below) when I run the demo programs.
Error using sosprogram (line 51)
No SDP solvers found.
Error in sosdemo1 (line 10)
prog = sosprogram(vartable); % No decision variables.
What is wrong with the installation ? I had already installed an SDP solver ( SDPNAL+ ) before installing SOSTOOLS so why is it still saying "No SDP solvers found" ?
I would be highly grateful if someone can guide me through proper installation steps involved.
The download cite for SOSTOOLS is given below and the instruction manual is attached alongwith.
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Sorry I come late, now it is 2020. Please noted to install the SDP solver: [sedumi] or other kinds of SDP solver, which is necessary to the SOSTOOLS.
While you can check on the reference website: http://sedumi.ie.lehigh.edu/ . Cheers.
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Hello, every one
1) I load the "barbara" image in MATLAB using the following command:
load woman
It is saved in workspace as "X" and its matrix class is "double". Then, I define "Y" as follows:
Y = uint8 (X);
the "Y" class is "uint8". The elements in "X" and "Y" are the same but when I use "imshow(X)" and "imshow(Y)", the results are different. why?
********************************************************************
2) When I use commands "[AX HX VX DX] = dwt2(X,'haar')" and "[AY HY VY DY] = dwt2(Y,'haar')" the results are the same but matrix elements of AX, HX, VX, DX are not in the interval [0 - 255]. Is it true?
********************************************************************
3) I use the following commands to save 3 types of the image in the current directory.
imwrite (X, 'barbara.bmp');
imwrite (X, 'barbara.tif');
imwrite (X, 'barbara.jpg');
Then I read them and save into 3 different matrices, X1, X2 and X3 as follows:
X1 = imread ('barbara.bmp');
X2 = imread ('barbara.tif');
X3 = imread ('barbara.jpg');
After that I see X1=X2 but X1 and X3 are different. why?
********************************************************************
4) I uses "dwt2" function for X, X1,X2 and X3. The results are different. why? Which format of the image should be used for DWT?
I look forward to hearing from researchers who know the answers. Thank you.
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imshow is used with uint8 data type
while double data type is used for arithmetic operations
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Please, I have completed my modeling and simulation is working fine for a sliding mode control system. However, I want to test the robustness of the controller with an input disturbance such as pulse and sinusoidal signal. Nevertheless, I am not sure if what i have done is correct. I conected the pulse signal with the input 'u' into the system via addition block of simulink. Please I have attached the coonection.
I would be gald for a better method of showing this because the plot is not giving desired result. I am using second order sliding mode - Twisting and Super-Twisting as my controllers. I am trying to investigate the differences between the two based on performances and others.
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Syeda Shafia Zehra
Thank you for the insight. Could you please enlighten me further on the use of the switch and the configuration of the swicth? several switches in simulink. But definitely i cant use manual swicth. Kindly offer more insight on the type of switch and how to configure it. Subsequently conecting it given the above attached picture of my work. I am really grateful fo the insight.
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what is the method to find natural frequency of a rectangular elastic membrane under fixed boundary condition. Using finite element method in matlab.
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Please, try https://acoustics.phys.msu.ru/teachers/shanin_files/FEM_book.pdf pp. 34-44 - you will find there theory and Matlab script...
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A simple cycle has been designed in Thermoflex software and the purpose is optimizing that via Genetic Algorithm in Matlab. would you aid me for linking them to each other?
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I am currently working on a research paper where l need to design a distributed formation tracking controller but l am having trouble with the simulation. I have read a lot of books on Matlab but l am stuck.
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Something seems missing from the denominator... Sum on vj but no vj in expression.
Please read again.
More important, explain your notations, and what the problem is about. Expressing an issue clearly forces you to understand it better.
Then get back to me on what to simulate and how, for this I could help.
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I′m trying to build a simulation about a divided wall column using open source programs (without MATLAB, Aspen, etc.). I would like to know if there is any methodology to program these kinds of simulators.
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1) Identify the reactions that are taking place
2) Develop a credible mechanism and rate expression
3) develop a mathematical representation of the reactions taking place (or at least the rate limiting step)
4) Adjust rate constants and possibly activation energy to match data.
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I'm working with precipitation data, soil moisture data, evapotranspiration data from various sources and resolutions. While using programming languages like MATLAB or Python for downscaling coarser data to finer resolution, we have a choice of selecting any interpolation or extrapolation method such as linear interpolation, cubic interpolation, Nearest neighbor interpolation, piecewise cubic interpolation, etc... Which interpolation and extrapolation methods are suitable from climatic variables precipitation, soil moisture, evapotranspiration, soil moisture index?
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I have used the delta method to downscaling the grid (raster data) at 1 km of spatial resolution. I am attaching two papers for you to consult.
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I am currently working on solving an ILP model using a branch and bound method which will be implemented by Matlab and in each node I need to determine an upper bound using Lagrangian relaxation method so I need to solve the dual problem using Cplex and the iterative procedure(to update multipliers) will be also implemented by Matlab.
I will be grateful if anyone had experience integrating Cplex with Matlab in a similar way, could help me?
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I am looking for free software or source code in Matlab, C, or FORTRAN codes for interpretation of SIP data acquired from laboratory experiments and field.
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Hi,
I have run my GA in Matlab. But I didn't save the Best fitness graph during the optimization run. I did save the optimization result as .mat file. My questions are;
1. Is it possible for me to extract and plot the Best fitness graph by using the optimresult/optimprob/options of the .mat file after the GA run has finished?
2. Did the Best fitness graph can only appear during the optimization run?
Thank you for your response.
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Thank you for all the answers
.
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Opposition based learning
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I have given some attachment below .I want to use the equation which I have written in my attachment for nonlinear curve fitting by Matlab script.
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Writing a complex equation like BCS is a complex task, But I can give you some hints and directions:
1- Take a look on how integral and differential equations a re written in MATLAB see https://www.mathworks.com/help/matlab/numerical-integration-and-differentiation.html
2- check how the curve fitting script is written in Matlab see
Also see the attached document for writing differential equations in Matlab
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Actually this is the impulse force, which is to be applied on the rod element?
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Piezo-electric actuator? A fast DC motor with ex-center element? Maybe?
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I have two sets of face images - RGB images, acquired from web-camera and Thermal images, collected using Optris PI450.
I want to find the temperature of face regions like nose, forehead, chin, etc. using the combination of visible and thermal images. For instance, I want to detect nose in visible images, and find corresponding pixel location in thermal images.
To start with, I did stereo calibration using a heated checkerboard, and found both camera's intrinsic and extrinsic parameters using MATLAB Stereo Calibration toolbox.
Any suggestion on how to proceed further will be grateful.
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Hello Namrata
Were you able to get Thermal Image using Homography, though it is now 2 years?
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I want to 3D plot the motion of an ROV on Matlab by using the runge-kutta method, if anyone has a link or the method to solve the stat equation , thank you very much for your help
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thank you very much for your answers, I was finally able to write the code and it works well, it was not easy because the Ki must be matrix and so on. PS: the 1st link does not work,
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Hello everyone,
Using the spectral collocation method (SCM), I have successfully obtained the complex wavenumber k, displacement U and stress field S of different LAMB modes.
However, when I used the obtained k/U/S form the SCM method to solve the LAMB wave edge reflection problem, I had trouble with the calculation of energy reflection coefficients.
The sum of all the non-zero?energy reflection coefficients (corresponding to the propagating modes)?should?be equal to 1,?but I?failed to get that right and the sum of those?coefficients turned to be?variable.
Power flux has been calculated as described in Mode-exciting method for Lamb wave-scattering analysis (JASA, 2004) by?Arief Gunawan, and Sohichi Hirose in the form:
<P> = Real (?-iw/2*intgrate(sigma*·(du/dt), -h,h) )
If anyone has ever met this problem or knows how to solve it? Or, if there is any program available online for us to use and study?
I have been checking my program over and over again?for half a month, but I still can't find the causes. Thank you so much for spending your time reading my question.?I would really appreciate it if you can help me with this problem.?
My program was written with reference to the article of Prof. Pagneux and?has been attached as NromalIncident-Vincent Pagneux way.zip, in which the?LambDispersionValidation.m can be run to check the basic?results of my program (compared with the online?program from https://www.mathworks.com/matlabcentral/fileexchange/73050-lamb-wave-dispersion-curve, as shown in the figure below).
To help you understand my program and save your time, I want to tell you some details about my codes:
  1. I can get the dispersion curves (as shown in the figure below). So I think the results of?complex wavenumber k?are right.
  2. For LAMB waves propagating in +x direction, the displacement field was assumed?as u = U*exp(i(kx-wt)).?The numerically obtained k?may have the form a + bi, a - bi, -a + bi, -a - bi (a and?b?are positive real numbers). In the?GetkInOrder.m, I have kept only those k with positive real part (+x propagating) and positive imaginary part (physically decaying with propagation).
  3. For LAMB waves propagating in -x direction, the displacement field was assumed as?u = U*exp(i(-kx-wt)),?so the k will be still kept?k = a+bi.
Best regards,
Hao Qiu
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Hi Steffen,
Thank you for your reply.
  • About the link error:
I think there may be some error with the Program.zip link. I have re-edited my question and attached my program as NromalIncident-Vincent Pagneux way.zip since I have been programming with reference to the article of Prof. Pagneux.
  • About the power flow
You are right. I have read that article before. The power flow associated with the complex roots near the free edge is not insignificant as shown in Eq. (11) in the paper you mentioned. However, while considering the area far away from the edge (several times the wavelength will be enough, I set x1 = 100m in my program), the power flux of the non-propagating modes can be neglected. This can also been validated with Eq. (11).
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I would like to figure out how to integrate evidence layers using Artificial Neural Network (ANN) for mineral potential mapping (MPM) in the Matlab step by step.
I will be grateful to you if you send me a film, pdf or link about it.
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Thank you dear Muhammad
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Hi All, While carrying out Panel Threshold regressions, most of the methods and statistical software seem to emphasize a balanced panel. For example, xthreg in STATA can only be used for balanced panel data. What are the options out there for unbalanced panel data for Threshold regression? For both dynamic and non-dynamic analysis. Especially would appreciate full paper, data and software codes that can be replicated. STATA, R, eviews or Matlab all are fine. Thank you.
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Hello, I do I deal with unbalanced panel data?
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Flood frequency analysis is mainly based on the assumption of stationarity of the data; however, in recent years, this assumption has been open to doubt. So before carrying out the FFA study, what are the most recommended statistical tests that should be applied to check the stationarity of time-series data?
Thanks in advance.
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Yes!
I have a same problem
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Matlab tools for Deeep Learning allow us to solve classification tasks with static features (e.g., pixels values of images) and tasks with dynamic features (time-series). For time-series it is recommended to use LSTM (Long Short Time Memory) layer. But how to build model, if we want to use simultaneously time-series parameters and some static parameters?
Naturally, it is possible to create a fictitious time series (with constant values) from each value of a single static parameter, but this will be very inefficient.
Thanks for your answers beforehand. Regards, Sergey.
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Hi Sergey,
Have you taken a look at so-called spatial-temporal deep learning models?
A survey about such models is avalable by following:
It is quite possible to incorporate higher dimensional topological features into these models. To get a better idea, refer to the following papers:
Regards
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Please I have been trying to get a plot as given in the attached picture. I have a code already which i have been trying to modify to give the grapgh as shown below. Although my own plot is that I want to compare three control methodologies.
1. I want the three parameters which are the outputs to be plotted (Y1 Y2 Y3) in relation to each of the controllers to have the same line style. The attached plot has two controllers. One is dashed line and another is solid line. I want my own to have an additional linestyle. Hence each line style represents each controller
2. I want to have legend in terms of the three controllers
3. I want the text label on the plots after plotting with the three controllers be Z_r, N_r and T_l as given in the reference attached.
Below is the code I want to modify. Likewise, Marker and Color may not be neccessary since it will be easier to distinguish as i explained above.
I have explored Matlab community and i saw couples of codes that i can adapt. Howerver, I have not been able to do so. I wonder if the plot was even done with Matlab?
I would appreciate suggestions on how to do the plots. Thank you
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with my matlab code as following
classNames = ["background","tumor"];
pixelLabelID = [0 1];
pxds = pixelLabelDatastore(im ,classNames,pixelLabelID, ...
'FileExtensions','.nii','ReadFcn',volReader);
Error using pixelLabelDatastore>parseInputs (line 202)
'FileExtensions' is not a recognized parameter. For a list of valid name-value pair arguments,
see the documentation for this function.
Error in pixelLabelDatastore (line 151)
[location, classes, values,params] = parseInputs(varargin{:});
Error in SEp1 (line 27)
pxds = pixelLabelDatastore(im,classNames,pixelLabelID, ...
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Hi everyone
I have some 3ddose files which are the out put of simulation by dosxyznrc and now I am going to draw DVH in CERR.
These 3ddose files are read in Matlab and by using CERR ,they will have been able to compare and plot DVH.
Has anyone had experience , how 3ddose file can be imported in CERR?
Any help will be appreciated.
Elham
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Hi Elham,
Do X, Y, and Z vectors have the same length and width in your 3ddose file?
Did you use the ready-made MATLAB program? In that case, can you please send the address to me?
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will the sbdart matlab code run on octave?
i heard it is available for online computations but couldn't find it any suggestions. i saw the link below but don't know how to run it
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Thank You Ma'am
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I am working on the application of a Local maximum-entropy approximation based meshfree method to the fluid problems.
As a first step, I chose the Convection-Diffusion problem to study and decided to validate my results with the classical SUPG FEM.
In order to first validate the SUPG FEM MATLAB code, a benchmark problem that has an analytical solution is taken and performed the convergence test. In SUPG FEM as I am increasing the number of nodes from 10 to 100 the error is gradually increased as follows
10 2.22E-05
20 6.30E-05
30 1.16E-04
40 1.79E-04
50 2.50E-04
60 3.28E-04
70 4.14E-04
80 5.05E-04
90 6.03E-04
100 7.06E-04
What are the possible mistakes that took place in my code?
Considered only homogeneous mesh for this work and used vpa (Variable precision arithmetic) function where ever necessary to ensure double-precision.
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As I have listed the results, The error is in the order of 10^-4 till 100 nodes. But the error is inclining.
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In the second phase of Response Surface Methodology, using the central composite design on input/ output data, I want to fit a second-order polynomial on the subarea to find the optimum combination. Is there any mathematical formulation or toolbox in Matlab that can give me the estimated coefficients? I should code this in Matlab and do not want to use Minitab or Design
Expert software and I have four input data which makes it to estimate 15 coefficients.
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Determine B =(inv (X'X))*X'*Y directly in the matlab/scilab console by first feeding X (design matrix ) corresponding to your design and then the observation vector Y into the console.
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Dear community,
I am trying to build a model of a Furuta pendulum in Simulink/Simscape. Unfortunately, when I try to linearize my model with the integrated Model Linearizer, I get an unexpected result. The evaluation of the linearized system shows, that it is only poorly controllable, although a classic Furuta pendulum should be fully controllable according to literature. Therefore I assume, that there must be something wrong with my model or the way I linearized it but I can′t figure out what it is.... I′d highly appreciate any help on that, as this is bothing me for quite some time now. The model is attached to this post. Furthermore I have attached a screenshot of the linearized system.
My controllability matrix (ctrb(A,B)) then looks like this with rank = 1, which I believe can′t be right...
Controllability matrix =
1.0e+26 *
0 0.0000 0.0000 -0.0000 0.0000
0.0000 0.0000 -0.0000 0.0000 -0.0007
0 0.0000 0.0000 -0.0000 0.0000
0.0000 0.0000 -0.0000 0.0000 -0.0015
0.0000 -0.0000 0.0000 -0.0000 9.2972
Thank you and best regards, Joo
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Apply Newton's law of motion for this pendulum to get linear.
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I want to write Matlab code using finite element method in order to solve the above problem but I didn't succeed because am not familiar with that Matlab programming however I have tried to give such code below which it dosn't work ,any help ?
-u''(x)+u(x)=(-4x^2-6) exp(x^2),u(-1)=u(1)=0, x\in ]-1,1[
[
My attempt code :
function [U] = EquaDiff2(n)
%----------------------------------
% d2u/dx2 + 6 du/dx + 9 u = x(1-x)
% u(-1) = 0 u(1)= 0
syms x x1 x2 real % déclaration de variables
symboliques
function [Ke, Fe] = MatElt2Nd(x1,x2) % déclaration de la fonction , Fonction pour calculer la
mat. et vect. élementairs
%----------------------------------
x = ]-1:2/n:1['; % modification d’1 borne
d’intégration
K = zeros(n+1 ) ;
F = zeros(n+1,1) ;
for i = 1:n
j = i+1;
t = [i j];
x1 = x(i);
x2 = x(j);
[Ke,Fe] = MatElt2Nd(x1,x2);
K(t,t) = K(t,t) + Ke;
F(t) = F(t) + Fe;
end;
K(1,:) = [];
K(:,1) = [];
F(1) = [];
U = K\F;
U = [0.0;U];
t = 0:0.01:1;
return
%-------------------------------------------
% Calcul de la matrice Ke et du vecteur Fe
%-------------------------------------------
function [Ke,Fe] = MatElt2Nd(x1,x2)
Ke1 = 1/(x2-x1)*[ 1 -1 % les modifications ne
touchent
-1 1 ] ; % essentiellement que les
matrices
Ke2 =(x2-x1)* [ 2 1 % élémentaires
1 2 ] ;
N = [(x-x2)/(x1-x2) (x-x1)/(x2-x1)] % fonctions de forme
Fe =simple( int(N' * (-4*x^2-6)*exp(x^2) , x, x1, x2) ) % vecteur Fe ;
Ke = Ke1 + Ke2 ;
return
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Hi, you can first rewrite your equation as a system of two first-order equations:
u'(x)=y(x)
y'(x)=u(x)+(4x^2+6)exp(x^2)
u(-1)=0 u(1)=0
Then you can define the shooting function whose parameter is z=y(-1) :
S: z --> S(z)=u(1)
To compute numerically S you simply have to call ode45.
Finally, using fsolve you can search for a zero of S, i.e. z such that S(z)=0.
Only some short MATLAB modules are required.
Best
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How to generating LDPC parity-check matrices in MATLAB [depend to length of my code-word] ?
I want to generate different coderate : 1/2, 1/3 and 3/4 using matlab.
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k=1088; %message length in bits
message=randi([0,1],k,1); %original messsage
n=2*k; %code length (message+parity bits), here you can control the rate
r=k/n; %code rate
% H matrix dimention x y
x=n-k;
y=n;
m=round(log2(n+1));
h = hammgen(m); %Parity-check and generator matrices for Hamming code
h=sparse(h);
MessagePadded=cat(1,message,zeros(size(h,2)-size(h,1)-k,1)); %padded with zeros
ldpcEncoder = comm.LDPCEncoder(h);
ldpcDecoder = comm.LDPCDecoder(h);
encData = ldpcEncoder(MessagePadded);
decoData = ldpcDecoder(encData);
for i=1:length(decoData)
if decoData(i)==true
B(i,1)=0;
else
B(i,1)=1;
end
end
isequal(MessagePadded,B)
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I have trained a model using GPR and want to see Min MSE PLOT. But matlab is showing model not optimized. How to generate this plot?
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i am using regression app in matlab.
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Just for those who recorded EEG data with Brain Vision Recorder and want to import that data into EEGlab (without using the Matlab Transformation tool in the BrainVisionAnalyser (BVA), because Matlab might be on a different computer than your BVA, or you dont have a BVA) here is a solution that might help you:
1. first you need to download the extension:
[in Matlab] run eeglab and in the GUI go to File -> Manage EEGLAB extensions -> Data import extensions -> and select "bva-io".
2. [if you have the BVA and did some preprocessing such as changed Sampling Rate etc] use the generic export tool (Export -> Generic Data) to export your data.
3. [in Matlab - EEGlab] load your dataset by starting eeglab -> file -> import data -> using EEGlab functions and plugins -> (at the Bottom) From Brain Vis. Rec. .vhdr file.
Hope it help,
Mitja
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where did you download the extension?