Mercurial > matrix-functions
view matrixcomp/sparsify.m @ 3:d24a00dabdc2 draft
Added first test and Makefile after figuring out how to!!! Also removed
fontconfig rubbish created by a bug in my GNU/linux system.
Note: review E.B. Davies's paper "Approximate Diagonalization" for tricky
diagonalization problems.
author | Antonio Pino Robles <data.script93@gmail.com> |
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date | Fri, 15 May 2015 20:24:25 +0200 |
parents | 8f23314345f4 |
children |
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function A = sparsify(A, p) %SPARSIFY Randomly set matrix elements to zero. % S = SPARSIFY(A, P) is A with elements randomly set to zero % (S = S' if A is square and A = A', i.e. symmetry is preserved). % Each element has probability P of being zeroed. % Thus on average 100*P percent of the elements of A will be zeroed. % Default: P = 0.25. if nargin < 2, p = 0.25; end if p<0 | p>1, error('Second parameter must be between 0 and 1 inclusive.'), end [m,n] = size(A); if ~isequal(A,A') A = A .* (rand(m,n) > p); % Unsymmetric case else A = triu(A,1) .* (rand(m,n) > p); % Preserve symmetry A = A + A'; A = A + diag( diag(A) .* (rand(size(n,1)) > p) ); end