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why do we initialize any vector or matrices with zero.
If you know you will be filling in the variable elements downstream anyway, it would be faster to just allocate the memory and n...

casi 3 años hace | 0

Respondida
Complex matrix multiplication with pagemtimes
This really has nothing to do with the maturity of MATLAB ... every language that uses BLAS routines in the background will have...

casi 3 años hace | 2

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Respondida
Matrix power vs for loop
Note that the A^endtime method is probably going to be more accurate as endtime gets larger. The loop method can have a tendancy...

casi 3 años hace | 0

Respondida
error: matrix dimensions must agree
I would presume you may need element-wise operators. Try this: func = @(K_a,freq)(-K_a./(tan(2*pi*freq*h.*(1 + 0.19./((K_a/60 +...

casi 3 años hace | 0

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Average every 3 rows of 1 column in a 12 x 8 array
E.g., Data = [ 34 6 4 -6.60874766440390 -40.7725049965035 16217 0.289000000000000 1.02200000000000 35 6 5 -6.54326464...

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Converting 2D cell array to 3D matrix
E.g., MyCell = repmat({(1:4)'},2,3) % small sample data [m,n] = size(MyCell); reshape(cell2mat(MyCell(:)').',m,n,[]) size(an...

casi 3 años hace | 1

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How can I calculate the "Median" of floating point numbers
E.g., x = randi(10,2,3) y = randi(10,2,3) z = randi(10,2,3) xyz = cat(3,x,y,z) result = median(xyz,3)

casi 3 años hace | 0

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Respondida
transposing 3d matrix with permute function
MATLAB does not store trailing singleton (1) dimensions beyond the 2nd dimension. Once you permute that 1 into the 3rd dimension...

casi 3 años hace | 2

Respondida
Scalar structure required for this assignment.
This? [Sis.On] = D_{:,2};

casi 3 años hace | 0

Pregunta

LU decomposition algorithm change
For this particular example: A=[ 1 2 3; 4 5 6; 7 8 9; 10 11 12]; I get two different results depending on...

casi 3 años hace | 2 respuestas | 0

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respuestas

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Inserting a double to a cell
E.g., x = randi(100,10,10) % sample data columns = [4,7]; % columns to check minx = min(x(:,columns)) % minimum of the two co...

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Using Matlab to solve 1D Schrödinger Equation (Strange Eigenfunctions)
Python: return is misspelled retrun The mL2V( ) function returns 1000*(y-1/2)**2 I don't see where y is defined prior to the ...

casi 3 años hace | 0

Respondida
1×0 empty double row vector using find
Welcome to the world of floating point arithmetic. For your specific example, they are not equal. E.g., x=[0 0.1 0.2 0.3 0.4 0....

casi 3 años hace | 1

Respondida
How to plot the first derivative of solution?
After the ode45( ) call, simply pass your x solution through your derivative function to obtain the xdot values. You can either ...

casi 3 años hace | 0

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optimizing: fastest way to detect if ANY points are within distance N of points?
Here is a naive brute force mex routine you can try out. It makes no attempts at cache optimization or multi-threading, and is p...

casi 3 años hace | 0

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"roots" call is not providing the correct answer
Rename your old roots file (preferred method) or move it to a directory that is not on the MATLAB path. That way it won't shadow...

casi 3 años hace | 1

Respondida
How can ı solve this error ??Unable to perform assignment because the size of the left side is 1-by-5 and the size of the right side is 26-by-1.
You could expand the size of the LHS array. E.g., poles_real(i, 1:numel(roots_poly)) = real(roots_poly); poles_imag(i,...

casi 3 años hace | 0

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angle of a vector centered at a certain point
Once you have the vectors, you can calculate the angles between the vectors using the technique I posted here: https://www.math...

casi 3 años hace | 0

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How to expand dimension of a 2D array
All MATLAB trailing singleton (1) dimensions beyond the 2nd dimension are not physically stored, and will not show up in a size(...

casi 3 años hace | 2

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A single precision matrix multiplication problem
Somewhat related side comments: In general, the BLAS/LAPACK libraries do not contain mixed type argument routines. E.g., there ...

casi 3 años hace | 2

Respondida
How is this even logical?
When assigning into rows or columns via indexing, MATLAB will conform a RHS vector from row or column to row or column if necess...

casi 3 años hace | 0

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Matlab crashes when running a specific Fortan MEX file under MacOS
The MATLAB Fortran API interface needs to be treated as a pass-by-reference interface. That means you need to have the exact typ...

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Respondida
What does [n==0] means?
Try it out and see: n = 3; N = 3; n == 0 n == N n = randi(4,1,10) - 1 n == 0 n == N Returns logical true/false where val...

casi 3 años hace | 0

Respondida
How to update a symmetric matrix?
E.g., M = rand(6)<0.3; M = double(logical(M+M')) % an arbitrary symmetric matrix VarMin= 1; % Lower Bound of Variables...

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Recursive Method returning answers backwards
This is a very convoluted way to program the Euler method. There is no need for recursion here, just use simple loops instead. ...

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How to randomize order of functions
E.g., Using the cell array approach with randperm: function [results] = runTests(testparameters) f = {@test1,@test2,@test3,@te...

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eval() is too slow to numerically evaluate a function with X(t) and Y(t).
Something like this? syms X(t) Y(t) Vfun = [2*X + Y ; cos(X)*X^2 + Y^3 ; 3 + sin(Y)] syms x y vfun = subs(Vfun,[X Y],[x y])...

alrededor de 3 años hace | 0

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Respondida
I have one column data 57600 points, how can i convert it to 240 by 240 matrix!
x = your column vector result = reshape(x,240,240); or you might need the transpose: result = reshape(x,240,240).';

alrededor de 3 años hace | 0

Respondida
I want to calculate pi^2 to 22 decimal places
You can use this excellent FEX submission by John D'Errico: https://www.mathworks.com/matlabcentral/fileexchange/36534-hpf-a-bi...

alrededor de 3 años hace | 2

Respondida
How to stop running code once conditions are met?
If your Birthday function is supposed to represent only one trial (a reasonable thing to do), then you should be returning n, no...

alrededor de 3 años hace | 0