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Walter Roberson


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44.926 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
expression is too large, symengine can't calculate
Create eqns = [obj.dx,obj.dS(:);obj.dSS(:)]; Now break that up into chunks. For example: At_a_time = 10; num_eqn = length(eq...

etwa 4 Stunden ago | 0

Answered
Better way to pull out values from a struct
Times = arrayfun(@(S) S.callsTable.Time, CT, 'uniform', 0); T = horzcat(Times{:}); The assignment to T will fail if the Time...

etwa 4 Stunden ago | 0

Answered
how to obtain volume data from X,Y,Z,c data to use slice() function?
N = 50; xvec = linspace(592447.8, 592463.9, N); yvec = linspace(507793.3, 507837.4, N); zvec = linspace(2553.6, 2559.9, N);...

etwa 4 Stunden ago | 0

Answered
Eliminate tables with more than 15% NaN data
filetables = load('C.mat'); numtables = numel(filetables); tablenames = fieldnames(filetables); droptable = false(1, numtab...

etwa 11 Stunden ago | 2

Answered
Subplot, 1 large and 2 small
subplot(2, 2, [1 3]) %draw for A subplot(2, 2, 2) %draw for B subplot(2, 2, 4) %draw for C

etwa 11 Stunden ago | 0

| accepted

Answered
Error using fprintf Unable to convert 'sym' value to 'double'.
fprintf(nru,'{ %.3f uta1 + %.2f uta2 = -%.2f\n',[UI1,SG13,SG12]); fprintf(nru,'{ %.3f uta1 + %.2f uta2 = -%.2f\n\n',[SG13,UI2,S...

etwa 11 Stunden ago | 0

Answered
Calling a function from a script
Example of calling a function from a script: x = input('Input x '); y = xsquared(x); disp(y) function y = xsquared(x) ...

etwa 11 Stunden ago | 0

Answered
Trying too run two functions in parallel where the functions have two outputs
funcs1 = {@linear_programming_bound, @linear_programming_bound}; arguments1 = {W,b,Xmins(:,j),Xmaxes(:,j); ...

etwa 11 Stunden ago | 0

| accepted

Answered
Solving Symbolic Equations with Solve-Creating a GUI
temp = struct2cell(rptas); results = vertcat(temp{:}); However, you need to be careful with this, as the order of fields in rp...

etwa 11 Stunden ago | 0

Answered
Cell2mat not working for unequal length cell data/array
Nmsg = length(canMsgs.Data); msglen = cellfun(@length, canMsgs.Data); maxlen = max(msglen); C = nan(Nmsg, maxlen); for i = 1...

etwa 12 Stunden ago | 0

Answered
solving equation with if statements
syms theta kappa alpha time y real eqn = y == piecewise(time < alpha, exp(-kappa*time), exp(-kappa)*exp(-theta*(time-alpha))...

etwa 12 Stunden ago | 0

Answered
How to read a binary file with below description?
filename = 'appropriatefile.les'; [fid, msg] = fopen(filename); if fid < 0 error('Filed to open file "%s" because "%s"', ...

etwa 13 Stunden ago | 0

Answered
I want to understand a function "fastmarchingmex" .
The source code for that function is available to employees and interns of Mathworks, but not to the public.

ein Tag ago | 0

Answered
Concerning some error For Loop in my optimal control problem
Inside a quoted string 'i' the symbolic engine will always interpret 'i' as sqrt(-1) and never as the current value of i You ...

ein Tag ago | 0

Answered
how to read complex file data to matrix
Sometimes easiest is to read the file as a character vector, use regexp to remove the space around the sign of the imaginary par...

ein Tag ago | 0

Answered
Unable to display symbolic object because 'symengine' was reset
You install more RAM. You are running out of memory during the symbolic computation. You should probably be using sig\der ins...

ein Tag ago | 0

Answered
GUI to interface Matlab with Omicron (Significance of the syntex used)
It is not impossible that there is a significance to the ' at that point, but chances are not high. For there to be a signifi...

ein Tag ago | 0

Answered
How to set() plot in matlab with cell array
You cannot do that. When you have multiple lines to plot then each of them must have its own line object h = plot(x, y_with...

ein Tag ago | 0

Answered
Build error: C++ compiler produced errors. See the Build Log for further details
You must install Visual Studio to use GPU Coder.

ein Tag ago | 0

| accepted

Answered
Code Explaination (For Loop)
The code is doing linear interpolation between column 4 and column 5, using abs(x) as the portion of the way between the columns...

ein Tag ago | 0

Answered
Data type conversion help
When you use () indexing with a table you get back a table. You need {} indexing rpt_row_sel{:, 2}

ein Tag ago | 1

| accepted

Answered
Why Genetic Programming result is not consistent?
Genetic programming is always random. And NO there is no way to get it to consider all combinations of operations while still...

2 Tage ago | 0

| accepted

Answered
How to read xls file without changing variable names.
Upgrade to a newer matlab release; that was an enhancement after your version.

2 Tage ago | 0

Answered
How to "call" a function
There is no difference in calling a function if you are in a script or in a function. You still use the same syntax [first...

2 Tage ago | 0

Answered
how to speed up startup of compiled application? Win 10, MCR 9.3
https://www.mathworks.com/matlabcentral/answers/99307-how-can-i-install-the-matlab-component-runtime-without-administrator-right...

2 Tage ago | 0

Answered
how can i convert image to text by using matlab code
Use fileread() to read the image file. uint8() that. Now you can use base64 to convert the numeric values to text. https://w...

2 Tage ago | 0

Answered
Is there a way to find the max value in an array without using the "max" command?
sort() and take the endpoint. Or loop comparing each entry to the largest so far and if the current entry is greater then upd...

2 Tage ago | 0

Answered
How can uicontrol be used to make an editable dropdown (eg combobox) control?
Only if you use a uicontrol style 'edit' together with the uicontrol style listbox . The primary value would be held in the edit...

2 Tage ago | 1

| accepted

Answered
How to do operations on nested cell array?
for K = 1 : numel(events) [~, idx] = max(cellfun(@std, events{K})); Events{K} = events{K}(idx); end I would not bother t...

2 Tage ago | 0

Answered
shadowed file constructor file conflict
Quit MATLAB and re-enter it.

2 Tage ago | 0

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