Walter Roberson

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49,961 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
Undefined function 'x' for input arguments of type 'double'. Why does this flag that particular line and nowhere else? Is there a was to fix it?
y=z(:,1); y=z(:,3); should be x=z(:,1); y=z(:,3);

6 hours ago | 0

Answered
How do you produce an empty plot if value is higher or lower than given user input value?
y=nan; custom=nan; If you want to produce an empty plot for that case. Your current code will not prod...

9 hours ago | 0

Answered
Have function use variables within workspace
Normal functions cannot see the variables in the workspace of the caller -- not unless the function specifically asks to look th...

10 hours ago | 1

Answered
Need help with inverse laplace
syms s tp T assume(T>=0) %THIS X_a=((1/s)-(1/(s+(1/tp))))*exp(-T*s) x_a=ilaplace(X_a)

11 hours ago | 0

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My while loop and rem function create an infinite loop
You do give a chance for the user to enter x again, so you are testing the same x each time.

11 hours ago | 0

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Answered
Draw multiple surfaces from different tables(.mat) files. Such that the different .mat files have different Color and names should be displayed on the surface
I already gave you instructions on how to do this, but you did not follow the instructions. Also, you did not deal with the fac...

12 hours ago | 0

Answered
± use in MATLAB
syms ALPHA syms delta_1 delta_2 assume(-0.008 <= delta_1 & delta_1 <= 0.008) assume(-0.002 <= delta_2 & delta_2 <= 0.002) CL...

13 hours ago | 0

Answered
Am I Going About This the Right Way?
No. You need to find the location x, y such that the total of (0.5*distance*volume) over each of the customers, is minimized. ...

13 hours ago | 1

Answered
Solve non-linear equations system parametrically, Why are the answers empty?
There are four solution sets, that look something like [X1 == 1, X2 == (cos(Lz1*h*sin(RootOf(Lz1^2*cos(Z)^2*h^2+cos(Z)^2*Z^2*k...

14 hours ago | 0

Answered
The limit of a symbolic expression
The limit of constant 0 times f(x) is 0 unless f(x) approaches infinity at the same rate that the constant 0 approaches being 0....

17 hours ago | 0

Answered
spline interpolation error , index in line 1
spline = spline(t,e_t); After that line spline refers to an array not the function. Use a different variable name.

17 hours ago | 0

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Answered
Is there a way to get an 8 x 1 matrix instead of 8 x 3 using dec2bin or any other?
string(dec2bin (2 ^ n-1: -1: 0)) This will be considered an array. The entries will be string objects such as "011". The en...

18 hours ago | 2

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Answered
using symbolic variable with spline interpolations
[~, coeffs] = unmkpp(pp); Splines are not a single equation in the sense of a single polynomial that works from beginning t...

18 hours ago | 0

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matlab function in simulink
You are in a MATLAB Function Block, so you need to follow MATLAB syntax. MATLAB does not have multiple assignment in the form...

19 hours ago | 0

Answered
Error using PARFOR: Index exceeds the number of array elements
global variables are not copied to workers when you use Parallel Computing Toolbox, and setting the variable on one worker does ...

19 hours ago | 0

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Answered
How can we solve this, how to convert mupad to live script?
A = [[2, 1, 1] [3, 4, 3] [3, 5, 4] [2, 6, 5]]; surf(A)

1 day ago | 0

Answered
Invalid expression. Need help fixing my function.
if score < 0 || score > 100

1 day ago | 0

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Answered
Linear programming code not showing the solution
Where do you assign something nonempty to vert? Why do you calculate y since you never use it?

1 day ago | 0

Answered
Solve system of equations with the symbolic matrix
T = sym('x', [4 4]); T(4,:) = [0 0 0 1]; T p_new1 = [2 0 0 1].'; p_old1 = [0 0 0 1].'; p_new2 = [3 0 0 1].'; p_old2 = ...

1 day ago | 0

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Answered
Logical with complex numbers in a vector
e = [-1e-9;3;9;0] t = sqrt(e); [real(t), imag(t)] t == 0 format long g e [real(t), imag(t)] You are being mislead by your...

1 day ago | 0

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Answered
Not Sure How to Call a Norm from Within a Function
N = sqrt(sum(y(:,4:7).^2,2)); plot(t, N)

1 day ago | 1

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Answered
How to show the image slice from the below example?
% This is a part of the code % Visualize the CT and SPECT together for m = 1:199 CT_img = new_CT(:,...

1 day ago | 0

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Answered
The variable ... appears to change size on every loop iteration. Consider preallocating.
word2 = char(zeros(1,L));

1 day ago | 0

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Answered
Solve symbolic equation system
That is a series of ODE. You will not be able to solve it with solve(). You could try it with dsolve([eqn1, eqn2, eqn3, eqn4]) ...

1 day ago | 0

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How can I re write this but with a different variable other than "syms"
% average of las 4 digitss avg=4; % get gama value gama=5+avg; % 5% relative error err=5/100; % defining the functio...

1 day ago | 0

Answered
Combine and average several *.mat files
matdir = 'name_of_directory'; %could be '.' outfile = 'path/to/output.mat'; dinfo = dir(fullfile(matdir, '*.mat')); filename...

1 day ago | 1

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Answered
count number of rows in csv outside of matlab
csvdir = 'appropriate_directory_name'; %use '.' for current directory csvFiles = dir(fullfile(csvdir, '*.csv')); filenames = ...

1 day ago | 0

Answered
how to draw 3d histogram of an image ad shown in figure
Histogram implies that you are binning the data, and the coordinates are associated with the edge or central value of the bin. 3...

1 day ago | 0

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Answered
How to Implement equationsToMatrix command
f=(Pr-Ps).^2-b1^2

2 days ago | 0

Answered
Why am I getting this error when trying to show a cell of an array? "Brace indexing is not supported for variables of this type"
Your file has no data (after at most 3 header lines). The textscan result is empty.

2 days ago | 0