Walter Roberson

Last seen: Today | Active 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. I am currently caught up to T0099119; if you are waiting on a reply from me for an older issue, please send me a reminder.

Programming Languages:
C, MATLAB, Shell, Perl, Fortran
Spoken Languages:
English

Statistics

All

View badges

Content Feed

Answered
MATLAB GUI does not work for others
The work-around is to change tnum(i) = vpasolve(snum(i)==s(t),t); to tnum(i) = vpasolve(snum(i)-s(t),t); snum(i) happens to ...

4 hours ago | 1

Answered
Is there a way to Rewrite a Symbolic Expression in Terms of nthroot?
syms x real g = x^(1/3) - 1 mapSymType(g, 'power', @(X) nthroot(children(X,1), 1/children(X,2))) This particular implementati...

9 hours ago | 0

Answered
Using the matlab app designer, I want to somehow run a function that can modify data within the app without specifically calling it.
function status(varargin) persistent app switch nargin case 1 assert(~isempty(app), 'statu...

9 hours ago | 0

Answered
i have the next error but idk wheres the problem.
You might need to set nlobj.Parameters to a cell array containing the sample time.

10 hours ago | 0

Answered
Creating an app using Matlabs App designer, need help displaying images in the app from and API.
[im, cmap] = imread(app.Flagimage.ImageSource); if isempty(cmap) if ndims(im) == 2 im = im(:,:,[1 1 1]); %gray t...

15 hours ago | 0

Answered
Raising a negative to a non-integer exponential
sym(-2)^(31/10) The -8 is real valued and 2^(1/10) is positive, so we can neglect them for a moment, and examine the (-1)^(1/10...

19 hours ago | 0

Answered
How do I write an array to a binary file?
"binary file" means different things to different people. The *standardized* "binary" formats that inherently support recordi...

1 day ago | 0

Answered
why my code run in online matlab, and in app has an error?
It looks like a bug in the detectSpeech code for R2023a if you call detectSpeech with more than one parameter. That section of...

1 day ago | 0

| accepted

Answered
combine large number of image blocks from file sequentially
imagedir = '1'; dinfo = dir( fullfile(imagedir, '*.jpg')); filenames = fullfile({dinfo.folder}, {dinfo.name}); numfiles = n...

3 days ago | 0

| accepted

Answered
Can I change email address in my profile?
See https://www.mathworks.com/matlabcentral/profile/community_profile/edit

3 days ago | 0

Answered
What are Your Thoughts on TMW Documentation Linking to the File Exchange
I have no problem with Mathworks documentation pointing to FEX contributions, even third-party FEX contributions. This may be b...

3 days ago | 0

Answered
Index in position 1 is invalid. Array indices must be positive integers or logical values. Error in book1 (line 8) D(2i+1,1)=1;
In MATLAB, 2i is notation that means 2 times sqrt(-1) so 2i+1 is a complex number. Complex numbers cannot be used as indices. I...

3 days ago | 0

| accepted

Answered
acker(): "Error using sym/poly". Why?
acker() is a now-undocumented function in the Control Systems Toolbox, in a directory reserved for "obsolete" functions. In othe...

3 days ago | 1

Answered
MATLAB error when run
You are asking to calculate and store data for 100 radial grid points for 100 samples per second for 2 complete years . 2 compl...

4 days ago | 0

Answered
How can measure distance after threshold
First trim the white border off of the image. Then binarize and take the inverse of the image, so that the black become 1 and th...

4 days ago | 0

Answered
How to avoid complex numbers out of Newton-Raphson?
Some of the issues are hidden because you are using vpa() in a number of places. When you take a numeric approximation to a sym...

5 days ago | 0

Answered
Fill missing observations for a sensor reading.
I suggest you use table2timetable and then retime

5 days ago | 0

| accepted

Answered
Error in batch image processing: Index exceeds the number of array elements. Index must not exceed 0.
The error is being generated against line 26 of jullly13.m which you do not show us the source code for. You show us the source...

5 days ago | 0

Answered
How to display a fprintf on designer panel (R2018b)?
The return value from fprintf is the number of bytes that have been written by fprintf(). fprintf() is strictly for sending data...

5 days ago | 0

| accepted

Answered
I get error when I try to test an agent trained on a PC( with GPU) on a second computer which has no GPU (Reinforcement Learning)
Your Training_Script1 is trying to load() a .mat file that has a gpuArray() object stored in it, but you are trying to do that o...

5 days ago | 0

Answered
Cropping and saving images: "unable to perform assignment because the size of the left side is 825-by-1081 and the size of the right side is 450-by-601."
% specify folder with uncropped images projectdir = '/Users/greencrystal19/Documents/MATLAB/numframe'; savedir = '/Users/green...

5 days ago | 0

| accepted

Answered
Byte Size of Fixed Point numbers in Matlab
embedded.fi are *objects* that include control information about the representation and the attached behaviour (such as overflow...

6 days ago | 0

| accepted

Answered
How to expend 1 dim for array ?
MATLAB does not exactly ignore trailing dimension of 1, but thinking of it that way is "close enough" for most work. Every arra...

6 days ago | 2

| accepted

Answered
¿Is it posible to save a .bmp image with resolution (dpi)?
BMP images do not have any defined metadata, other than the image size and encoding information, and possibly an icc profile. T...

6 days ago | 0

Answered
Where can I get the License Agreement of MATLAB and Simulink Student Suite License?
license_filename = fullfile(matlabroot, 'license_agreement.txt'); edit(license_filename) If you would be getting academic cr...

7 days ago | 1

Answered
Index in position 2 exceeds array bounds
f1 = matlabFunction(D2ynum,"Vars",{x, [p Dp q Dq D2q]}) 5 variables bunched together, so f1 is going to expect to be able to in...

8 days ago | 0

Answered
How to remove frame appear as a result of thresholding
Your image has a white border that you need to trim out. bb1 = imread('bb1.jpg'); imshow(bb1); title('original'); set(gca, 'v...

8 days ago | 0

Answered
Error using eps CLASSNAME argument must be a class that supports EPS, such as 'double' or 'single'.
decic does not permit any of its inputs to be symbolic, and the ode function you pass to it cannot return symbolic. You can d...

8 days ago | 0

Answered
Like to have input user command for cases
switch and case

8 days ago | 0

Answered
write table on screen
Create a cell array and use writecell

8 days ago | 0