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Diffstat (limited to 'sourcecodes/bnt-master/KPMstats/multipdf.m')
| -rw-r--r-- | sourcecodes/bnt-master/KPMstats/multipdf.m | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/sourcecodes/bnt-master/KPMstats/multipdf.m b/sourcecodes/bnt-master/KPMstats/multipdf.m new file mode 100644 index 00000000..592d0004 --- /dev/null +++ b/sourcecodes/bnt-master/KPMstats/multipdf.m @@ -0,0 +1,45 @@ +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 \ No newline at end of file |
