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Walter Roberson


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45.000 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
How to solve this error presented when compiling .cpp files to mex?
const int *dim1 = mxGetDimensions(prhs[0]); mxGetDimensions does not return int* https://www.mathworks.com/help/matlab/api...

circa 2 ore ago | 0

Answered
How can i make a 1 count as 11 if its best in blackjack
if score <= 11 && ismember(1, hand)

circa 9 ore ago | 0

| accepted

Answered
How I can Solve an Advanced Cubic Equation
syms x a r eqn = x^3*a^2*(r-1)+x^2*a*(a-2*(r-1)) - x*(2*a+1)+1; sol = simplify(solve(eqn, x, 'maxdegree', 3)); The second and...

circa 9 ore ago | 0

Answered
Modifying a message / dialog box in a function for different parts of the function and automatically closing?
https://www.mathworks.com/help/matlab/ref/uialert.html uialert() with 'modal', false should return a handle that you can manipu...

circa 10 ore ago | 0

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Answered
Generating covariance from matrix
N = 20; y = rand(N,1); autocov = zeros(2, 2, N); for i = 1:N autocov(:, :, i) = cov(y(i:19),y(i+1:20)); end The result...

circa 15 ore ago | 0

| accepted

Answered
How to generate all possible connection with graph theory function
https://www.mathworks.com/matlabcentral/answers/286462-how-to-find-all-possible-paths-from-one-node-to-another-node#answer_223...

circa 15 ore ago | 0

Answered
Not enough input arguments
You cannot run that code by simply pressing the green Run button to run it. You must go down to the command line and invoke the ...

circa 15 ore ago | 0

Answered
Using wcompress in Matlab
'haar' is not one of the valid compression methods for wcompress() https://www.mathworks.com/help/wavelet/ref/wcompress.html#f1...

circa 15 ore ago | 0

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Answered
how to plot array ? i am using display instruction but i m not able to plot that data on xy plane
pf_n = 0.35:0.05:0.5; ac = (10000.0:10000.0:50000.0).'; C = (1.11 .* Bavg .* ac .* Kw .* pf_n); vs = vr./(1-s); L_W = Q./(...

circa 16 ore ago | 0

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Answered
How to extract a coefficient from a specific symbolic variable?
Sometimes you can isolate() the variable in the equation, after which coeffs() the lhs() of the equation. Otherwise, lhs(eqn)-r...

circa 16 ore ago | 0

Answered
Errors using function and fsolve
The function you are trying to find the zero of, must return a scalar. Your formula involves surr.h which is a vector, so your f...

circa 17 ore ago | 0

Answered
Is the function "minimize " included in MatLAB ?
No it is not included. You can get it from http://www.cs.toronto.edu/~hinton/MatlabForSciencePaper.html

circa 18 ore ago | 0

Answered
Problem with Cluster command
Z = linkage(squareform(Y)) ;

circa 19 ore ago | 0

Answered
Surface integral calculation over a segment defined by two points
Xq=linspace x1 to x2 and Yq=linspace y1 to y2, using the same number of steps. Now use those as the query locations in an interp...

circa 20 ore ago | 0

Answered
Check number of windows prompt open
Use .Net to start the processes. https://www.mathworks.com/matlabcentral/answers/497886-finding-pid-of-external-process-called-f...

circa 20 ore ago | 0

Answered
cubic equation solution simple and fast way?
If you have numeric coefficients, use roots()

circa 20 ore ago | 0

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Answered
I did plot(x,y) with a set of data that is not in oder, and now my line plot looks terribly wrong. How can I fix this?
Before doing any processing, sortrows data based on column 2. https://www.mathworks.com/help/matlab/ref/double.sortrows.html

circa 20 ore ago | 0

Answered
Choose random element of vector
P1 = randi(length(Vector) - 1); P2 = randi([P1+1,length(Vector)]) ; x1 = Vector(P1) ; x2 = Vector(P2) ; Note that ...

circa 20 ore ago | 2

Answered
Subtract elements greater than a threshold?
mask = YourArray > 2^19 - 1; YourArray(mask) = YourArray(mask) - 2^20;

circa 22 ore ago | 0

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Answered
Corresponding vector values to array values
Vector = [1 31 11 40 34 46 19 25 24 0 0]; nodes = Vector(Vector ~= 0); total = sum(Matrix(sub2ind(size(Matrix), no...

circa 22 ore ago | 1

Answered
Index in position 4 exceeds array bounds (must not exceed 1).
You define Ex(i,j,n,1) = 150; % but we have no reason to expect that on the line M11(i,j,n,g) = (1/(4*dt))*(g1+g2...

circa 22 ore ago | 0

Answered
How to Export Contour Plot as Shape File if Output is of Data Type 'Double'?
https://www.mathworks.com/matlabcentral/answers/358316-how-can-i-export-a-matlab-contour-as-a-polygon-shapefile

1 giorno ago | 1

Answered
is there something similar to imregistrer but for video?
"Are there functions similar to Imregster but for videos?" No. "Or do I have to save the files as individual frames and go...

1 giorno ago | 0

Answered
HOW TO DELETE A LINE FROM A CREATING FILE
writetable(T(2:end, :),'file.csv') This assumes that you want to write out the variable names but skip the first row of the...

1 giorno ago | 1

| accepted

Answered
how to combine matrices
A*10+B

1 giorno ago | 1

| accepted

Answered
Undefined function 'diff' for input arguments of type 'function_handle'.
There are two major diff() functions in MATLAB. One of them is the numeric difference operator, roughly x(:, 2:end) - x(:, 1...

1 giorno ago | 0

Answered
Issues defining dot product function
In newer versions of MATLAB, if you use a name as both a function and a variable, then it will treat it as always being a variab...

2 giorni ago | 1

Answered
Magnitude, row and column in a Matrix
Use the two output form of min(). The second output will be the appropriate row numbers.

2 giorni ago | 0

Answered
function handle in a loop
Provided that the two calculations return the same size of values, and provided that neither calculation ever returns inf or nan...

2 giorni ago | 0

| accepted

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