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Thread Subject:
Improve speed of skew matrix calculation.

Subject: Improve speed of skew matrix calculation.

From: Richard Crozier

Date: 2 Jun, 2011 15:19:04

Message: 1 of 1

Can anyone suggest a way to improve the speed of the following small function which I must call many times:

% Compute a skew matrix from its axial vector Theta.
% function S = skewmat(theta)
function S = skewmat(theta)
    if m*n == 3
        S=[ 0 -theta(3) theta(2); ...
            theta(3) 0 -theta(1); ...
            -theta(2) theta(1) 0];
    elseif m*n == 2
        S=[-theta(2) theta(1)];
        error('theta must be a 3-vector');

Specifically, it is the line:

        S=[ 0 -theta(3) theta(2); ...
            theta(3) 0 -theta(1); ...
            -theta(2) theta(1) 0];

which is the problem. I'm guessing it's impossible to improve this, but thought I'd ask anyway. I presume mexing the function will not give much benefit as it's all basic matlab operations already.


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