Walter Roberson
43,633 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.
Walter Roberson's Badges
The contributor whose answers received the most acceptances in 2018
Awarded to Walter Roberson on 18 Jan 2019
The contributor whose answers received the most acceptances in 2017
Awarded to Walter Roberson on 02 Jan 2018
Contribute at least one answer each month for 36 consecutive months
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2016
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2015
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2011
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2012
Awarded to Walter Roberson on 20 Jul 2017
The contributor whose answers received the most acceptances in 2013
Awarded to Walter Roberson on 20 Jul 2017
Accept 50 answers given by other contributors
Awarded to Walter Roberson on 20 Jul 2017
Reach 25000 reputation points
Awarded to Walter Roberson on 20 Jul 2017
Answer 50 questions that were unanswered for more than 30 days
Awarded to Walter Roberson on 20 Jul 2017
100 of your answers have been accepted
Awarded to Walter Roberson on 20 Jul 2017
Provide your first answer ever to someone else's question
Awarded to Walter Roberson on 20 Jul 2017
Solve a problem for the first time
Awarded to Walter Roberson on 10 Jun 2017
Integration output is NaN
You have a sub-expression ./(neta.*rho.*P.*z) When z is 0, that is a division by 0. When you are working numerically and z is ...
10 hours ago | 0
Error using eval when load many files in recursive
Don't use eval(). Construct your filenames using sprintf() and use the function form of load instead of the command form. http:...
16 hours ago | 1
Index exceeds the number of array elements (1) error on line 10
if P3(i)>P2(i); Q3(i) = (P3(i)-P2(i))/R2; else Q3 = 0; end The else of that overwrites all of Q3 with a scala...
17 hours ago | 0
| accepted
Disable windowkeypressfcn when specific child is on focus (app designer)
foo = uicontrol('style','slider', 'min', 0, 'max', 1); foo.Callback = @(hObject, event) fprintf('slider %g gco %g\n', double(hO...
19 hours ago | 0
Sort Index - Bug
>> [a, sort_index]=sort([100;20;30;40]) a = 20 30 40 100 sort_index = 2 3 4 ...
21 hours ago | 1
| accepted
imbinarize vs im2bw
label2rgb(label) is equivalent to label2rgb(label, 'jet') which triggers 'jet' to be executed with no parameters. When jet is ex...
24 hours ago | 1
How to update struct array fields with mutiple values
t = num2cell(1:10); [A.B] = t{:}; See comments for the case where the struct does not already exist.
1 day ago | 3
| accepted
append a text file to structure
fileread() is the easiest way. However if your file happens to contain utf8 characters I would want to double check whether f...
1 day ago | 0
How do I add row and column separators, and a border in a table so it looks like a real table?
You cannot do any of those things in r2019a. As of R2019b it is possible to use variable names that are not matlab identifier...
2 days ago | 0
Find minimum of an n variable function, n is like 800+
No. With 800 variables and non linear curv, it is unlikely that a global minimizer will find the global minimum. Especially so ...
2 days ago | 1
Is it possible to select an m-file for a "MATLAB function" block in Simulink?
No, you cannot load files into MATLAB Function Block. You can use the MATLAB Function Block as a very thin wrapper that just...
2 days ago | 0
How to show tf function to text box?
sys_char = evalc(sys); sys_cell = splitlines(sys_char); sys_cell = sys_cell(2:end-2); %some useless empty lines set(handles...
2 days ago | 0
Is it possible to restore a deleted mat file?
Sorry, not through any method provided by Mathworks. Your operating system or third-party utilities might provide undelete meth...
2 days ago | 1
| accepted
is there any way to put two plots in one legend entry?
That happens automatically unless you do one of the following: call legend with a single legend entry, such as inside a loop or...
2 days ago | 0
How do I remove leading characters from a string?
segments = regexp(dummy{1,1}{i,1}, '\t', 'split'); Perhaps you could have used readtable() on the ascii file: it would like...
2 days ago | 1
| accepted
Block Error, Singularity in Solution?
What I had to do to get your model to execute without error message, was to uncomment the saturation block that feeds the 1D loo...
2 days ago | 0
How to reference a variable saved as .mat file to execute code
t = cyc_mph(:,1); Vmph = cyc_mph(:,2); for tidx=2:length(t)-1 a = (Vmph(tidx+1)-Vmph(tidx-1))/(2*(t(tidx+1)-t(tidx-1)));...
3 days ago | 1
| accepted
Help needed: empty plot when plotting for loop
Do not assign to Pw. Instead assign to Pw(i-1)
3 days ago | 1
| accepted
How to use webcam given in our systems?
If the camera is built in to your system then you need https://www.mathworks.com/matlabcentral/fileexchange/45183-image-acquisit...
3 days ago | 0
feval error in GUI implementation
You have function uipanel1_CreateFcn(hObject, eventdata, handles1) function Reader1Correct set(handles1.uipanel1, 'Back...
3 days ago | 1
| accepted
How to filter certain parts of a string.
S = char(wdoc.Content.Text); x = regexp(S, '^Introduction:.*?(?=^\nSummary:)', 'match', 'lineanchors');
3 days ago | 0
| accepted
re-insall MATLAB because of changing to a new computer
https://www.mathworks.com/matlabcentral/answers/142388-how-do-i-transfer-a-student-or-home-license-to-a-new-computer#answer_145...
3 days ago | 0
How do I replace multiple strings in text file at the same time?
S = fileread('YourFileNameHere.txt'); newS = regexprep(S, {'C-C', 'A-A'}, {'D-D', 'C-C'}); This replaces C-C with D-D everywhe...
3 days ago | 1
| accepted
Conversion to logical from optim.problemdef.OptimizationConstraint is not possible. Expressing a condition for a parameter.
A = b + x*(a-b)
3 days ago | 0
| accepted
Communication Toolbox comm.GeneralQAMTCMDemodulator Question
No. It is a .p file and cannot be editted.
3 days ago | 0
Why I am getting "Constraints are not satisfied within constraint tolerance." from using "gamultiobj"?
Infeasible individuals are present in the final population. This means that not enough feasible locations were found to displa...
3 days ago | 0
gui uitable choice list linkage
This cannot be done with a uitable for traditional figures. uitable for traditional figures implement menus by setting the ent...
3 days ago | 1
How to set the volume of beep sound and save it as wav?
You forgot to mention that you are using Psychtoolbox 3. audiowrite('NameOfWavFile.wav', beepWaveform, 44100); However, it is ...
4 days ago | 0
| accepted
help me debug this script!
n = 1:35 dataset_pfc_tar_57_n = dataset_pfc_tar_57(n,:) With n being a vector of length 35, dataset_pfc_tar_57_n is going to h...
4 days ago | 0
| accepted
Why does the resolution become extremely bad when increasing the linewidth when using the the circle as marker.
OpenGL has no built-in markers. All that it has are built-in square points. Therefore in order to create the markers, MATLAB has...
4 days ago | 0
Select a Web Site
Choose a web site to get translated content where available and see local events and offers. Based on your location, we recommend that you select: .
Select web siteYou can also select a web site from the following list:
Americas
- América Latina (Español)
- Canada (English)
- United States (English)
Europe
- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)
- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)