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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

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Answered
I think the error is in the filename please solve it quickly
when the code emits the message about entering the student ID, the person running the code needs to type in a numeric student nu...

4 hours ago | 0

Answered
How do I create a new variable with another variables' value as its name?
There are very few places in MATLAB that require a bare variable name with no possibility of any kind of indexing. The ones that...

5 hours ago | 2

Answered
Is it possible to create multiple parallel pools simultaneously
https://www.mathworks.com/help/parallel-computing/run-code-on-parallel-pools.html says You can have only one parallel pool at a...

14 hours ago | 0

Answered
why is my ea not being recognized?
if f(xl) * f(xu) < 0 In the case where that does not hold true, the for loop is never entered and ea is never assigned to. Not...

14 hours ago | 0

Answered
How can I do scatter density plot inmatlab?
See https://www.mathworks.com/matlabcentral/fileexchange/65166-densityplot-x-y-varargin and https://www.mathworks.com/matlabcent...

16 hours ago | 0

Answered
How to find a unique indicator of a specific matrix?
As of R2022b you can use keyHash . Before that, https://www.mathworks.com/matlabcentral/fileexchange/31272-datahash but see htt...

16 hours ago | 0

Answered
how to replace variable by another variable
if you are using the symbolic toolbox then subs()

1 day ago | 0

Answered
Numeric derivation from iminfo
unfortunately in practice the large majority of the time, doing this computation is useless. A lot of images do not have the res...

1 day ago | 0

Answered
How do I create a mathematical model from a given data using MATLAB
It can be shown by constructive proof that given a finite set of distinct input coordinate lists of finite values with finite re...

1 day ago | 0

Answered
Predictors must be a numeric array, a datastore, or a table.
your responses in ylabel1 is a cell array of scalar numbers. cell array with numeric content is supported only for sequence to s...

1 day ago | 0

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Answered
NetworkWrongType: First argument must be a SeriesNetwork, DAGNetwork, dlnetwork, or layerGraph.
feedforward networks are "shallow" networks. Export to onyx only supports "deep" networks. (I do not whether onyx networks su...

1 day ago | 0

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Answered
guidata() not working as expected
The problem is not with guidata. guidata is holding the handle of the object, not the values associated with properties. There i...

1 day ago | 0

| accepted

Answered
I keep getting "Error using / Arguments must be numeric, char, or logical. " in bayesopt.
doc bayesopt fun accepts x, a 1-by-D table of variable values, and returns objective, a real scalar representing the objective ...

1 day ago | 0

Answered
How to resolve this error?
@(fzero_start)Defelection_Function_with_Target(fzero_start<target) You are asking fzero to invoke a function Defelection_Functi...

1 day ago | 0

Answered
how can i save the results of multiple executions?
You should learn this pattern: tvals = 0.1:1:10; num_t = numel(tvals); results = zeros(num_t,1); for t_idx = 1 : num_t ...

1 day ago | 0

Answered
How To: Multi-level subindexing
Yes, it is, but it is fairly ugly to do so. You can call upon subsref() manually, possibly having used substruct() to help build...

1 day ago | 0

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Answered
Preference settings for command line table display
toolbox/matlab/datatypes/tabular/@tabular/display.m is the implementing function for that, and it is not configurable. The work...

1 day ago | 0

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Answered
Loading data from .mat file and converting them to string array
load ('GradNames.mat', 'GN') means that a variable named GN is to be looked for inside the file, and if it is found, loaded int...

1 day ago | 0

Answered
How can I enable the syntax for a function and the window for the workspace variables?
See https://www.mathworks.com/help/compiler/mcc.html#d124e20756 for a description of code suggestions. For this to happen you m...

3 days ago | 0

Answered
display text when running exe in dos command window
When you compile use the -m option; in particular do not use the -e option. https://www.mathworks.com/help/compiler/mcc.html#d1...

3 days ago | 0

| accepted

Answered
Two MATLAB questions about syms
You are using the "matrix" keyword, which treats the names as matrices . In order to "expand" it you would have to convert to in...

3 days ago | 0

Answered
plot function overwrites axes
Unless you have "hold on" (or the internal equivalent property) then each time you use a "high-level" graphics call, MATLAB does...

3 days ago | 2

Answered
How to present (x(t))'', (θ(t))'' in symbolic version matlab?
syms b J g L M m syms F(t) N(t) P(t) theta(t) x(t) xp(t) yp(t) x_prime = diff(x); x_dprime = diff(x_prime); theta_prime = di...

3 days ago | 0

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Answered
How can I draw contour lines in my problem ?
https://www.mathworks.com/matlabcentral/fileexchange/38858-contour-plot-for-scattered-data is a File Exchange contribution for c...

3 days ago | 0

Answered
im trying to solve this system of 10 equations
M=10 deltax=2*sym(pi)/M syms f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 U1=f1*exp(1i*deltax)+f2*exp(1i*2*deltax)+f3*exp(1i*3*deltax)+f4*e...

3 days ago | 0

Answered
Solving a non-linear system of equations
You cannot. You have unknowns to a fractional power: the system cannot possibly be linear. You also have a^2*b which again is n...

3 days ago | 1

Answered
Find location of 2 black dots in the image
See regionprops probably with 'Centroid'

3 days ago | 1

| accepted

Answered
Is Matlab 2012b still under support?
https://www.mathworks.com/support/requirements/previous-releases.html -- R2012b supported Windows 8, not Windows 10 at all. htt...

3 days ago | 0

Answered
Differential equations by separable equations (Symbolically)
Math says that a diff eqn solvable by separable equations is one of the form f(x,y)=p(x)h(y) or p(x)+h(y)=0 For the first form,...

3 days ago | 0

Answered
Error when importing data
you need to reinstall matlab. dbtype uiimport 1 should show function varargout = uiimport(varargin) but on your s...

3 days ago | 1

| accepted

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