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Walter Roberson


43.984 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
Adding two arrays of different sizes together evenly without messing cumulative sum.
C = A + B / length(A);

etwa 2 Stunden ago | 0

Answered
Ask user for another image or abort
Delete the "clear all" -- you should never include "clear all" as part of a program that does computation. (But you could have a...

etwa 3 Stunden ago | 0

Answered
Extracting the same column in a cell array for anova
col_to_extract = 1; the_columns_as_cells = cellfun(@(C) C(:,col_to_extract), YourCellArray, 'uniform', 0); You cannot, howev...

etwa 3 Stunden ago | 0

Answered
Taylor Series Approximation of Sine
nn=720; nn is 720 angle=linspace(-2*pi,2*pi,nn) linspace(something, something, nn) creates a vector exactly nn in length, so ...

etwa 3 Stunden ago | 0

| accepted

Answered
is table performance still the slowest in MALTAB R2019b?
Tables will always be slower than struct. I guarantee it.

etwa 6 Stunden ago | 0

| accepted

Answered
How to know the real row and column indices of a pixel in the image
which_pixel = 37987; [r, c] = ind2sub([s(1), s(2)], which_pixel); And remember that row corresponds to Y and column correspo...

etwa 20 Stunden ago | 0

Answered
Error using handle.handle/set Invalid or deleted object.
In your callback for edit1 you replace the handle with the value extracted from the handle. That is confusing at the very least....

ein Tag ago | 0

Answered
Regexp Find Digit between two hyphens
(?<=-)\d(?=-) Is one of the ways. (?-)\d(?-) might work

ein Tag ago | 0

| accepted

Answered
how to plot roots with a value used in the function?
for b = 0:10 p = [1 b -20]; r = roots(p); plot(b, r, 'k*'); hold on end hold off

ein Tag ago | 0

| accepted

Answered
x domain for figure
I do not understand what your notation about (x covers this domain) means. However I can point out that 1:0.1:200 does not inclu...

ein Tag ago | 0

Answered
signal processing buffer timeline
buffer() from the Signal Processing Toolbox can handle overlap. If you are asking about timeseries objects, then the answer is ...

ein Tag ago | 0

| accepted

Answered
How can I get the first row of different matrices into one matrix?
for iteration = 1 : 7 this_result = something \ something_else; combined_results(iteration,:) = this_result(1,:); end...

ein Tag ago | 0

Answered
Principal component analysis pca
if j==NSamples You did not assign to j by that point in the code, so it has its default value of sqrt(-1) which does not equal ...

ein Tag ago | 0

Answered
How to copy and paste the code with matlab layout when asking question here?
Look in the toolbar at the section marked "CODE", and click on the icon that looks like a > symbol. That will give you a code en...

2 Tage ago | 2

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Answered
How can i fix the error "Error using inline Input must be a character vector." and "Error in (line 9) g=inline(f);"
inline can only be used with character vectors. Your f is a double precision scalar. If you were to format it into a characte...

3 Tage ago | 0

Answered
solving equation contains lambertw function
The Symbolic Toolbox has lambertw

3 Tage ago | 0

Answered
How to clear file name and file path information?
Use '' or "" as the value instead of []

4 Tage ago | 0

| accepted

Answered
why ismember({struct.name},{'*.mat'}) returns zero while struct.name='basevalues_Mean_r.mat'?
ismember() never does wildcarding. It only does exact matches. regexp() does matching but the handling of wildcards is differen...

4 Tage ago | 1

| accepted

Answered
How to find minimum number of largest square of 1 in an 2D bool matrix
D = bwdistgeodesic(logical(YourImage), ~YourImage); Now iterate. if there are no finite values in D, break the loop. Find the l...

4 Tage ago | 0

Answered
how can i convert 1xn to mxn matrix ?
Use persistent variables in your function. The first 19 times the function is called, just store the 100 values passed in. The 2...

4 Tage ago | 0

Answered
Mat2Cell error when splitting an image up into smaller images
function blockImages = splitImageIntoBlocks(image, blockSizeRow, blockSizeCol) % blockSizeRow: Rows in block % blockSizeCol: C...

4 Tage ago | 0

| accepted

Answered
How can I print each piece of data in the following colum while iterating through a for loop with fprintf
It is possible to build up tables one column at a time. In order to do so, you need to work with character arrays and sprintf, o...

4 Tage ago | 0

Answered
'trapz' to find area under curve not working
x=length(y) is a scalar value, just the length. You then pass that one length as the X coordinates and pass all of y as the Y co...

4 Tage ago | 0

| accepted

Answered
Extract data from cell
YourCell(~cellfun(@isempty,YourCell))

4 Tage ago | 0

| accepted

Answered
Getting rid of a for loop
value1 = find(input(1:end-2) > input(2:end-1) & input(2:end-1) < input(3:end)) + 1; value2 = input(value1);

4 Tage ago | 1

| accepted

Answered
The crtrp function from the genetic-toolbox doesn't work
Line 34 can be deleted.

4 Tage ago | 0

Answered
difference between two programs
X=imread('mosque.jpg'); The great majority of .jpg are RGB (grayscale is possible but very rare.) [n,m]=size(X); size() of a...

4 Tage ago | 0

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Answered
X and Y must be same length, however they already are?
You do not store any x values, so it is [] after the reading loop.

4 Tage ago | 1

| accepted

Answered
Why does solve() parametrize the results in the conditions?
Your nonnegative and positive constraints together with the ^2 impose boundaries. The equation has to be solved in ways that the...

5 Tage ago | 0

| accepted

Answered
How can I solve the error of {Undefined operator '.^' for input arguments of type 'optim.problemdef.OptimizationExpression'}?
You cannot fix that problem in that release. The first release or two of Problem Based Optimization supported only linear proble...

5 Tage ago | 1

| accepted

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