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Walter Roberson


43.311 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
plotting multiple surfaces out of a 3d variable
Look in the File Exchange for "vol3d v2" Or perhaps you should just use slice https://www.mathworks.com/help/matlab/ref/slice.h...

ongeveer 9 uur ago | 0

Answered
Is there a way to continue operation during input()?
https://www.mathworks.com/matlabcentral/fileexchange/8297-getkeywait The below two mostly rely on Psychtoolbox https://ww...

ongeveer 12 uur ago | 0

Answered
How to set constraints of griddata results are all non-negative?
The griddata and interp1 and interp2 methods that do interpolation (so everything except nearest or next or prev) are all subjec...

ongeveer 12 uur ago | 0

Answered
Store function in an array
A = @(c) 3.*c +1; B= @(c) [A(c) A(c) A(c);... A(c) A(c) A(c);... A(c) A(c) A(c)]; C= @(c) det(B(c)); D= f...

ongeveer 21 uur ago | 0

Answered
Why do I not get the whole domain plotted?
You do not get a plot up to 20E9 because your calculation overflows to infinity. The below does not overflow to infinity, but i...

ongeveer 21 uur ago | 0

Answered
How can I set the colors in the legend if I show a number of legend elements which is lower thatn the number of plotted functions?
The trick for custom legends is to use for k = 1:num2show bh(k) = bar(nan, 'color', BarColors(k, :) ; end legend...

1 dag ago | 0

Answered
ode for different time intervals
It is valid to test if t < stoptime1 inside an ode function. However, you need to make two calls to ode45 [t1, y1] ...

1 dag ago | 0

Answered
Cpu usage in parrallel running mode
Have a look at the attached modified version of your code and see if it does what you want. I am not confident that my changes m...

1 dag ago | 0

Answered
index exceeds the number of array elements error
Looking at your code, I speculate that a is datatype uint8() When you have a/B with a uint8 divided by a double or another uin...

1 dag ago | 0

| accepted

Answered
How to use textscan on a cell array without a loop?
See my answer at https://www.mathworks.com/matlabcentral/answers/476452-splitting-one-column-into-multiple-columns# on how to pr...

1 dag ago | 0

Answered
how do i re-run a script so that it takes the updated information from another script?
MATLAB will normally notice changes to .m files that are on the current path, but not if they are installed under the MATLAB ins...

1 dag ago | 0

Answered
How do I get subs to behave as desired for symbolic expressions ... does collect change an expression?
collect(f,x) is a different expression with a different internal symbol than f is. isAlways(f==collect(f,x)) It is tempting to...

1 dag ago | 0

Answered
Splitting one column into multiple columns
input = {'0.17 1.7285 0.001763792 1.000977 56651.41 0.000017652 DHT11, OK, 35.0,'; ...

2 dagen ago | 1

Answered
How to find first row with a nonzero element in an image matrix?
find(any(any(YourImage, 3),2),1,'first')

2 dagen ago | 0

Answered
What is the meaning of "Index in position 1 exceeds array bounds (must not exceed 1)".
Use the flow shown in https://www.mathworks.com/help/symbolic/odefunction.html#bvlo6zg-1 Replace [M,F]=massMatrixForm(eqs,vars...

2 dagen ago | 1

Answered
concatenating arrays and matrix
Borrow my code from your previous question https://www.mathworks.com/matlabcentral/answers/475006-threshold-multiple-values-at-t...

2 dagen ago | 0

| accepted

Answered
Write line by line a separated .csv file with a string \t an integer \t [a n*2 matrix written in line with commas and semicolon]
You will find it tricky to output the variable-length data if you use fprintf() in vectorized form. It is possible, but the code...

2 dagen ago | 0

Answered
Simulink Question - How to input a decimal value and output hexadecimal string?
Which release are you using? Until R2019a, signals cannot be char. The work-around is to return uint8(dec2hex(value,SIZE)) . Whe...

2 dagen ago | 0

Answered
Trimming matrices to smallest size
minsize = min(cell2mat(cellfun(@size, S(:), 'uniform', 0))); newS = cellfun(@(M) M(1:minsize(1), 1:minsize(2), 1:minsize(3)), S...

2 dagen ago | 0

| accepted

Answered
How do i fix error : 'model' parameter must be a character vector?
[net,tr] = train(net, data_norm,group); y = sim(net, data_norm); y is going to be numeric and the same size as group result =...

2 dagen ago | 0

Answered
How do I allow user to choose either a folder or an image(or selective images) to run the rest of the functions?
choice = menu('How do you want to select images?', 'by folder', 'individual image'); switch choice case 0 %user c...

2 dagen ago | 0

Answered
Re-read the variable name
In https://www.mathworks.com/matlabcentral/answers/475899-how-to-properly-convert-variable-names-into-a-chain-of-strings-in-ma...

2 dagen ago | 0

| accepted

Answered
Run a loop every hour regardless of its calculation time!
https://www.mathworks.com/help/matlab/matlab_prog/use-a-matlab-timer-object.html

3 dagen ago | 1

Answered
Loading text files by looping through two number sequences
You do not need two loops. You can use a routine such as https://www.mathworks.com/matlabcentral/fileexchange/10959-sort_nat-nat...

3 dagen ago | 0

Answered
Try catch together with dbstop
Instead of using dbstop at that point, use keyboard() which gives you a command prompt in debug mode.

3 dagen ago | 1

| accepted

Answered
work with matrix of words and number
[unique_names, ~, idx] = unique(YourCell(:,1)); mean_per_word = accumarray(idx, cell2mat(YourCell(:,2)), [], @mean); output = ...

3 dagen ago | 0

Answered
Hex to Signed Int conversion of 16bit values in a Table with data type 'cell array of character vectors'
temp = uint16(arrayfun(@(S) sscanf(S, '%x'), YourTable{:,3:6})); output = reshape( typecast(temp(:), 'int16'), size(temp)); Wh...

3 dagen ago | 1

| accepted

Answered
How to label the adjacent same value in a matrix
bwlabel(A==1,4)

3 dagen ago | 0

| accepted

Answered
how to skip an error inside a loop?
try x = data.timepoints(6).cells{89, 1}{2, 1}{2, 1}(3); catch ME try x = data.timepoints(6).cells{90, 1}{2, ...

3 dagen ago | 0

| accepted

Answered
How can I put an arc symbol above a letter?
$\widehat{ab}$ gives something arc-ish $\stackrel{\frown}{ab}$ gives an arc, if not the prettest of them. Or $\frown \atop ...

3 dagen ago | 0

| accepted

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