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Walter Roberson


Last seen: Today |  Active since 2011

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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
Matlab-Excel shape PROBLEM
Create a vector containing the number of consecutive elements needed to move into each row. Not the indices, the count. So for e...

5 hours ago | 0

Answered
Correlation between 2 vectors give a matrix full of Nan
t = linspace(0,1) .'; %COLUMN A=5; f=1; ph1=0; cost=A*cos(pi*f*t+ph1); cost2 = A*cos(2*(pi*f*t+ph1))+1; c = corr(cos...

7 hours ago | 1

Answered
Array Problem How can I unpack an array? why the firt element pf my array is always 0?
[I1; I2; I3]= I; That code is valid only if I is a function (not function handle) that returns at least 3 outputs. It...

7 hours ago | 0

Answered
How do I generate a random signal that follows normal distribution of mean value 0 and standard deviation 10 ?
N = 1e7; target_std = 10; target_mean = 0; data = randn(1,N) * target_std + target_mean; %crosscheck mean(data) std(da...

8 hours ago | 0

Answered
this code fails with one file and one sub-folder /help/deeplearning/ug/train-deep-learning-network-to-classify-new-images.html#
If you only have one input then splitting is not going to work. Note also that if you only have data for one class then trainin...

9 hours ago | 1

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Answered
The code is plotting $R_0$ against two parameters
I had to guess about the range of alpha_1 and alpha_3 that you wanted to plot. The contour turns out solid color because the va...

9 hours ago | 0

Answered
Need help solving and plotting a first order pde
You have the derivative of tau with respect to t, so tau is a function of t. You wish to plot tau vs gamma, so tau is also a fu...

10 hours ago | 1

Answered
wfbm function wierdly crashes for a range of hurst exponent
H-(1/2) is passed to an internal function named alphacfs . In that function I = 1:1000; cka = gamma(alpha+1)./(gamma(I).*ga...

1 day ago | 0

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Answered
find the longest diagonal sum of a matrix.
When you press the green Run button, that is equivalent to running the function from the command line with no parameters. When ...

1 day ago | 0

Answered
Only perform a function when the working dialog is not closed
See uiwait and waitfor See also questdlg() /help/matlab/ref/inputdlg.html#d126e819840 in particular th...

1 day ago | 0

Answered
What difference does the choice of FIK make?
/matlabcentral/answers/93105-what-are-the-lm_license_file-and-mlm_license_file-environment-variables-an...

1 day ago | 0

Answered
How can i preprocess the rice colored image before applying this code
You need to convert the image to grayscale and save it to 'rice_preprocessed.png' For anything else, you should consider buildi...

1 day ago | 0

Answered
I am a university student and this is my university email: redacted@eng.zu.edu.eg Can I get Matlab for free? If possible, how do I get the activation key?
There are three possibilities here: Your university might have arranged with bat365 to support bat365 licenses for all el...

1 day ago | 0

Answered
How can I find the two intersection points of the x and y axis of two equations in Matlab?
Example with deliberately different equations. You can study the techniques and appy them to your own code. syms x y eqn1 = y ...

1 day ago | 0

Answered
error: Unsupported input format for From Workspace block 'untitled/From Workspace1'. Available formats are double non-complex matrix, a structure with or without time, or a st
When you use From Workspace, then you need to be importing something that has a time component attached to each measurement, suc...

1 day ago | 0

Answered
How can I mark the central point in annotate box
Suppose you have BB, an N x 4 array of bounding boxes of the form [x y width height] . These might have come from regionprops('B...

1 day ago | 0

Answered
Out of memory - dsolve 3rd order system
syms y(t) t; Dy = diff(y, 1); D2y = diff(y, 2); f = 10*exp(-t); sysB = diff(y,3) + 7*diff(y,2) + 8*diff(y,1) + 9*y == diff(f...

1 day ago | 0

Answered
How can I write a rational functions?
Example that is deliberately different than the function you are using. You can study the techniques here and easily write your ...

1 day ago | 0

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Answered
ga Taking too Much Time wtihout any Results
demand = table2array (mainData(9:62 , 2:21)); That is a 2D array. expDemand = expValue(demand, meanDemandResize, stdDemandResi...

1 day ago | 0

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Answered
how I can fix sample time in ode45
You cannot do that. ode45() is always a variable-step solver. So is ode15s, ode23s, ode78, ode113, ode89. If you need a fixed s...

1 day ago | 0

Answered
Solve these unkowns x and y using these 2 simultaneous equations
syms m3R3l3 m4R4l4 Eq1 = 2760 * sind(sym(200)) + m3R3l3 * sind(sym(107)) + m4R4l4 * sind(sym(307)) == 0 Eq2 = 2760 * cosd(sym(...

1 day ago | 0

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Answered
How to read a binary file and then classify it?
This assumes that the data really is int32, which I am not convinced of. FileName = '1.dat'; file_id=fopen(FileName,'r'); d...

1 day ago | 0

Answered
How to close only anova figures
close(findall(0, '-depth', 1, 'Type', 'figure', 'Name', 'N-Way ANOVA')) The anova function does not produce any graphics, so th...

1 day ago | 1

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Answered
Regression Learning Error Message on Command Window
Somewhere in your MATLAB path, you have a height.m file that is interfering with MATLAB's height function. Looking at the error...

2 days ago | 0

Answered
why it does not work ?
missing end statement no assignment to the output variable out

2 days ago | 0

Answered
Use num2str in for loop
Please read http:/matlabcentral/answers/304528-tutorial-why-variables-should-not-be-named-dynamically-eval fo...

2 days ago | 0

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Answered
How to add more information to plot help-box?
See datacursormode for the more general function. In the particular case of what MATLAB refers to as "chart objects" (which it ...

2 days ago | 0

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Answered
How do I declare multiple variables with a rule for naming?
Is there a one- or two-liner way of doing this pattern? Yes, there is a way. But that does not mean it is a good idea. Can you...

2 days ago | 0

Answered
Assigning values to a preallocated variable costs more time than to a non-preallocated variable?
a(:) = b*c; In MATLAB, as each expression is calculated, the result has to be stored in memory along with information about th...

2 days ago | 1

| accepted

Answered
Why do I get this Error using . "Array indices must be positive integers or logical values."
The code splits apart the name at '_" characters, so for the name "Exp_21_5_e" parts(1) would be "Exp", parts(2) would be "21", ...

2 days ago | 0

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