Hi, A matrix operation is that of stacking the columns of a matrix one under the other to form a single column. This operation is called "vec" or "cs" (c)olumn (s)tring Example A is a m * n matrix vec(A) = reshape(transpose(A),(m*n,1)) How can I copy the result of vec(A) into the ith column of another matrix called B ? Thanks in advance. Nils
From: "Nils Wagner" <nwagner@isd.unistuttgart.de>
A matrix operation is that of stacking the columns of a matrix one under the other to form a single column. This operation is called "vec" or "cs" (c)olumn (s)tring
Example
A is a m * n matrix
vec(A) = reshape(transpose(A),(m*n,1))
I assume you mean: def vec(A): reshape(transpose(A), (m*n,1)) First off, the following is a bit simpler and means you don't have to carray m and n around def vec(A): reshape(transpose(A), (1,1))
How can I copy the result of vec(A) into the ith column of another matrix called B ?
B = zeros([m*n, p]) B[:,i:i+1] = vec(A) However, I don't think this is what you really want. I suspect you'd be happier with: B[:,i] = ravel(A) Ravel turns A into an m*n length vector [shape (m*n,)] instead of m*n by 1 array [shape (m*n,1)]. If all you want to do is insert it into B, this is going to be more useful. tim
participants (2)

Nils Wagner

Tim Hochberg