Tagged Questions
1
vote
3answers
38 views
How to multiply a matrix by a scalar value in MATLAB under a condition
In matlab I have a matrix with random numbers between 0 and 100.
All numbers below 10 shall be multiplicated by two.
testmatrix = [1,2;11,90]
should turn into [2,4;11,90]
Executing conditional ...
2
votes
2answers
61 views
Take the product of all nonzero elements in each column of a sparse matrix
Is there a well-vectorized way to take the product of all the nonzero elements in each column of a sparse matrix in octave (or matlab) (returning a row-vector of products)?
0
votes
2answers
75 views
matlab vector addition like multiplication, without for loop
Normally when one adds two vectors this is what happens
[1 4] + [2 5] = [3 9]
I want it to do this:
[1 4] + [2 5] = 3 6
6 9
So basically addition like how multiplication ...
-4
votes
1answer
77 views
matrix column multiplication
i have a matrix NV but now i want to multiply only the 2nd column by 2
how should i go about doing this? this is my current code:
NV=zeros(10,10);
g1= 1:1:10;
n=2;
for b=1:n
NV(:,b)=10.^(g1/10);
...
3
votes
2answers
629 views
opencv - image multiplication
hi, i'm trying to play a little bit with Mat class.
I want to do a product element wise between two images, the c++/opencv port of MATLAB immultiply.
This is my code:
#include ...
5
votes
2answers
146 views
3d matrix by column vector multiplication
I have a 3d (or in general n-dimensional) matrix A with dimensions
size(A) = [d1 d2 d3 ... dn].
Now I want to do a vector multiplication with a column vector v over one of the dimensions (as I ...
2
votes
3answers
136 views
Matlab matrix row to row multiplacation of two matrix dimensions not agree
I have two matrix A and B for example
A = [ 1 2 3; 5 4 3; ...] and B = [ 1; 2; 3; 4; 5; 6] (row matrix)
and I want to have this
A*B = [1*1 2*1 3*1; 5*2 4*2 3*2; ...] without a loop. Is it ...
2
votes
3answers
349 views
Multiplying Cell with elements of a matrix Matlab
I have a 1xm cell array A{}, with each element of the array being NxN matrix and a matrix W(N1,m).
I need to calculate
Sum(j) = W(j,1)*A{1,1} + W(j,2)*A{1,2}
and I am doing the following:
for ...
1
vote
2answers
94 views
Warning: “Parethesize the multiplication of 'D' and its transpose to ensure the result is Hermetian.”
As you see in the screen shot above, I have the following expression in my Matlab m-file code:
K = P * D * D' * P;
Where, P is an nxn matrix, and D is a nx1 column vector (n=4, if it matters).
Why ...
2
votes
1answer
75 views
Creating a new probabilistic matrix from two existing ones according to prespecified rules in MATLAB
I have a problem in my MATLAB code. Let me first give you some explanation about the issue. I have two matrices which represent probabilities of specific outcomes of events. The first one is called ...
2
votes
2answers
583 views
Matlab: Multiplying select rows every nth interval
I have a 63row x 7column matrix.
xmax=63;
ymax=7;
for i=1:xmax
for j=1:ymax
n=(i-1)*ymax+j;
matrix(i,j)=n;
end
end
1 2 3 4 5 6 7
8 9 ...
1
vote
2answers
227 views
Multiplication of Vectors with diagonal of a matrices from t to t+1 in Matlab
Still very new to programming...
I have 9x1 Vectors at time t, t+1, t+2 etc.
[10 10 10 10 10 10 10 10 10]'
and matrices. Each matrix is 9x9 and also at time 1, t+1, t+2 etc. =
1 0 0 ...
