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Walter Roberson


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45,032 total contributions since 2011

I do not do free private consulting. If you want to bring my attention to something, send a link to the MATLAB Answers location.

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Answered
how to preallocate rows or columns of matrix through iteration?
locs = zeros(length(X), length(Y)) ;

5 hours ago | 1

| accepted

Answered
Where are "files installed for your end user" are saved in the installation directory using compiler?
Make sure that they are in your current directory at the time you use MATLAB Compiler, and do not use a path when you load. Or i...

6 hours ago | 0

Answered
encoder and decoder design using ldpc
You cannot modify the size of the matrix returned by that function.

6 hours ago | 0

Answered
Matlab find and print coordinates of array values
[row, col] = find(A>=42); fprintf('(%d, %d)\n', [col(:), row(:)].')

6 hours ago | 0

| accepted

Answered
creating circles for multiple points with viscircle
viscircles([t(:), z(:)], 0.5)

7 hours ago | 0

Answered
pcolor-plot move along the z-axis
Replace pcolor(X, Y, Z) With surf(X, Y, -20*ones(size(Z)), Z, 'edgecolor', 'none' )

9 hours ago | 0

Answered
My plot is not showing a line? Why?
Remove the plotting loop and use plot(r*10^9,Net_Energy,'g')

20 hours ago | 0

Answered
How to change the marker symbol on the plots generated by anovan function?
The third output of multcompare is the figure handle of the figure it drew into. Assuming that you call that fig ch = fig.Chil...

1 day ago | 0

| accepted

Answered
Inadvertent RMDIR execution during navigation down a path to a working directory
Sorry, there is probably no way to recover them, short of typical Windows undelete tools or professional data recovery services....

1 day ago | 0

Answered
How can I find an uifigure?
If you create the uifigure with HandleVisibility, 'on', then you can findobj(groot, 'type', 'figure') otherwise you need find...

1 day ago | 0

Answered
Evaluating Function at Matrix ?
F = @(x) exp(5*pi*(x-0.5)./(7*0.5)) .* (cos(5*pi*(x-0.5)./(7*0.5)) - sin(5*pi*(x-0.5)./(7*0.5))); A = randn(11,5); F(A)

1 day ago | 1

| accepted

Answered
Symbolic variables that display as a combination of Greek characters and normal letters in Live Scripts
This was changed as of R2019a . F__a is F with superscript a and F_a is F with subscript a . F_dot and F_hat are recognized nice...

1 day ago | 0

Answered
how to fit exponential distribution function on data?
You do not have an exponential distribution. (1 minus an exponential) is not an exponential. On the other hand if you fit using...

1 day ago | 0

Answered
Undefined variable, when variable is actually defined
You do not initialize thplot, so it is assigned a value only if for iStep=1:nStep executes at least one step. The for loop wou...

1 day ago | 0

| accepted

Answered
Index 3D Array with 2D logical array
You can do things like mask1 = false(size(A)); mask2 = mask1; B3 = repmat(B, [1 1 3]); mask1(:,:,[1 2 3]) = B3; mask2(:,:,[...

1 day ago | 0

Answered
how to read a really large lines of data(ascii file format) to a table
filename = 'YourFile.txt': [fid, msg] = fopen(filename); if fid < 0 error('Failed to open file "%s" because "%s"', filena...

1 day ago | 0

Answered
Second order ODE with dsolve
ode = diff(y,t,2) == a.*d) + b.*y - diff(x2,t)./10 + x1; You are missing a ( . Also, dy is not defined. Perhaps d) is intended...

1 day ago | 0

| accepted

Answered
Compiled version not working because of path
You need to modify your startup.m so that it does not add anything to the search path if isdeployed() is true.

1 day ago | 0

Answered
Concerning 1D data interpolation and use of Julian date function.
Change load('In_Flight_Data.mat'); To Ds = load('In_Flight_Data.mat'); dataTot = Ds.dataTot; datethermica = ...

1 day ago | 0

Answered
can someone solve this problem with dsolve?
What problem? That *is* the solution. Remember that many many integrals do not have a closed form solution.

1 day ago | 0

Answered
Can I install Matlab for Linux on personal laptop (Windows 10) if its already installed there Matlab for Windows?
Yes. The license is associated with the host, not the operating system. In some cases you might need to use Linux persistent ...

1 day ago | 0

Answered
Output an error message for executed command
You need try/catch around the execution of each statement that needs separate handling. If you are able to put the code for e...

1 day ago | 0

Answered
stem fuction shows error everytime
The stem.m file that it lists in the error message: you need to rename it to something else. For example mystem.m

2 days ago | 0

Answered
Can I install Matlab on a Surface Pro?
Yes, at least for the 5th generation onwards . However it is not recommended for the 4 gigabyte RAM model. At the moment I do...

2 days ago | 0

Answered
warning while running optimization tool
We can predict that your objfun has a place where you use Variable(Parameter) where you should have Variable.*(Parameter) Tha...

2 days ago | 0

Answered
Solving a matrix with multiple unknowns
LL_mat is a symetric non zero 10*10 matrix You have 10 equations in 8 variables. There will seldom be a solution.

2 days ago | 0

Answered
Char array to cell array
cellstr(val) You might want str2double( cellstr(val) )

2 days ago | 0

Answered
How do you evenly quantize an image to a certain number of bits?
Most of the time it is not possible to evenly quantize an image to a particular number of bits that is smaller than the original...

2 days ago | 0

Answered
How to use SUM of Series in Matlab with .txt files?
num = 0; denom = 0; for n=1:N num = num + (v1(n) - v2(n)).^2; denom = denom + v1(n).^2; end PRD = sqrt(num ./ deno...

2 days ago | 0

Answered
How can I resize an array without interpolating new values or mark the original ones?
| was wondering if there is a way to assign the vallues from the 75x265 matrix to the corresponding places in a 2160x2560 area w...

2 days ago | 0

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