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Walter Roberson


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44.941 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
Matlab support for 3D cameras
https://www.mathworks.com/help/supportpkg/turtlebotrobot/ref/getdepthimage.html https://www.intel.ca/content/www/ca/en/suppor...

alrededor de 6 horas ago | 0

Answered
How to convert gray image to HSV plane S - value image?
Hsv=rgb2hsv(repmat(YourMatrix, 1, 1, 3)); S = Hsv(:, :, 2) ; By the way the results are all 0. The h plane is all 0 too....

alrededor de 7 horas ago | 0

Answered
Can I have an older runtime environment than the complier version I am using?
No, there must be an exact match right down to update number.

alrededor de 13 horas ago | 0

Answered
12bit to 8 bit and Windowing
In older MATLAB see mat2gray, which has a deceptive function name and is not restricted to grayscale like the name suggests. ...

alrededor de 17 horas ago | 0

Answered
Symbolically differentiation a function w.r.t a function
You cannot differentiate a function with respect to a different unknown function with normal calculus, because you cannot know t...

alrededor de 17 horas ago | 1

Answered
Problem in displaying numbers
format long g

1 día ago | 0

| accepted

Answered
Compare and select values from an matrix.
min(A(1:2:end,:), A(2:2:end, :))

1 día ago | 0

| accepted

Answered
Error in resizing GUIDE gui
Change line 2765 of guidefunc from if ~strcmpi(get(children(i),'Units'), 'normalized') to if hasfield(childre...

1 día ago | 0

Answered
Using equationTomatrix changes the order of units in the final matrix. How do you maintain the order?
Pass in the vars option to the function to get the results to be in that order.

1 día ago | 0

Answered
create a vector without for
a=1:10; b=1:10; c=1:3; d=1:5; [A, B, C, D] = ndgrid(uint8(a), uint8(b), uint8(c), uint8(d)) ; v = [A(:), B(:)...

1 día ago | 1

| accepted

Answered
Issue with running a script calling "parts" function on the MATLAB Online R2019b
https://www.mathworks.com/matlabcentral/answers/481537-submitwithconfiguration-not-working-in-matlab-r2019b

1 día ago | 0

| accepted

Answered
VERY slow for loop
You do not use the variable i inside your for loop, so you are testing the entire energy variable of the table every time throug...

1 día ago | 1

| accepted

Answered
How to assign numbers to letters of the alphabet. Ex. A/a=1 B/b=2
https://www.mathworks.com/help/matlab/ref/lower.html https://www.mathworks.com/help/matlab/ref/ismember.html https://www.math...

1 día ago | 0

Answered
Unique Number Assignment To Each Time
Use the third output of unique(). Or use findgroups()

1 día ago | 0

Answered
plotting ode warning with nor plot returned
You dsolve() and store the answer but then you try to fplot the unprocessed A and B. At the very least you would want to plot S....

2 días ago | 0

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...

2 días 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...

2 días 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);...

2 días ago | 0

| accepted

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

3 días 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

3 días 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...

3 días 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) ...

3 días 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); ...

3 días ago | 0

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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...

3 días 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...

3 días ago | 0

| accepted

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))...

3 días 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"', ...

3 días 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.

3 días 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 ...

3 días ago | 0

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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...

3 días ago | 0

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