Samples elements of X so result uses at most maxmegs megabytes of memory.
X must be an n dimensional array with the last dimension used to index samples of X. So
for example if X has size d1 x d2 x...x dn-1 x dn, it is treated as having dn elements
of size (d1 x d2 x...x dn-1), and the resulting array Xsam will have dimension d1 x d2
x...x dn-1 x dn' where dn' <= dn.
Different types of arrays require different amounts of memory. Each double requries 8
bytes of memory, hence an array with 1.024 million elements of type double requires 8MB
memory. Each uint8 requires 1 byte, so the same size array would require 1MB. Note
that when saved to .mat files arrays may take up more or less memory.
Note, to see how much memory a variable x is using in memory, use:
s=whos('x'); mb=s.bytes/2^20
INPUTS
X - n-dim array of size (d1 x d2 x...x dn-1) x dn (treated as dn elements)
maxmegs - maximum number of megs Xsam is allowed to take up
OUTPUTS
Xsam - n-dim array of size (d1 x d2 x...x dn-1) x dn' where dn'<=dn
keeplocs - vector of indicies kept from X; Xsam=X(:,..,:,keeplocs)
EXAMPLE
% Xsam should have size: 1024xround(1024/10)
X = uint8(ones(2^10,2^10));
Xsam = randomsample( X, 1/10 );
% Xsam should have size: 100x10x~(1000/8)
X = rand(100,10,1000);
Xsam = randomsample( X, 1 );
DATESTAMP
29-Sep-2005 2:00pm