comparison toolboxes/FullBNT-1.0.7/KPMstats/multipdf.m @ 0:e9a9cd732c1e tip

first hg version after svn

+function p = multipdf(x,theta)
+%MULTIPDF Multinomial probability density function.
+%   p = multipdf(x,theta) returns the probabilities of 
+%   vector x, under the multinomial distribution
+%   with parameter vector theta.
+%
+%   Author: David Ross
+
+%--------------------------------------------------------
+% Check the arguments.
+%--------------------------------------------------------
+error(nargchk(2,2,nargin));
+
+% make sure theta is a vector
+if ndims(theta) > 2 | all(size(theta) > 1)
+    error('theta must be a vector');
+end
+
+% make sure x is of the appropriate size
+if ndims(x) > 2 | any(size(x) ~= size(theta))
+    error('columns of X must have same length as theta');
+end
+
+
+%--------------------------------------------------------
+% Main...
+%--------------------------------------------------------
+p = prod(theta .^ x);
+p = p .* factorial(sum(x)) ./ prod(factorial_v(x));
+
+
+%--------------------------------------------------------
+% Function factorial_v(x): computes the factorial function
+% on each element of x
+%--------------------------------------------------------
+function r = factorial_v(x)
+
+if size(x,2) == 1
+    x = x';
+end
+
+r = [];
+for y = x
+    r = [r factorial(y)];
+end