comparison toolboxes/FullBNT-1.0.7/KPMtools/mk_stochastic.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function [T,Z] = mk_stochastic(T)
+% MK_STOCHASTIC Ensure the argument is a stochastic matrix, i.e., the sum over the last dimension is 1.
+% [T,Z] = mk_stochastic(T)
+%
+% If T is a vector, it will sum to 1.
+% If T is a matrix, each row will sum to 1.
+% If T is a 3D array, then sum_k T(i,j,k) = 1 for all i,j.
+
+% Set zeros to 1 before dividing
+% This is valid since S(j) = 0 iff T(i,j) = 0 for all j
+
+if (ndims(T)==2) & (size(T,1)==1 | size(T,2)==1) % isvector
+  [T,Z] = normalise(T);
+elseif ndims(T)==2 % matrix
+  Z = sum(T,2); 
+  S = Z + (Z==0);
+  norm = repmat(S, 1, size(T,2));
+  T = T ./ norm;
+else % multi-dimensional array
+  ns = size(T);
+  T = reshape(T, prod(ns(1:end-1)), ns(end));
+  Z = sum(T,2);
+  S = Z + (Z==0);
+  norm = repmat(S, 1, ns(end));
+  T = T ./ norm;
+  T = reshape(T, ns);
+end