prod_index {PhylogeneticEM} | R Documentation |
Product of elements of a matrix
Description
prod_index
return the product of chosen elements of a matrix.
Usage
prod_index(X, Id)
Arguments
X |
a matrix with p rows and K column. Each row contains the number of partition in 1<=k<=K groups for one of the p children of a given node |
Id |
a vector of length p, result of the function |
Details
This function is to be used in sum_simplex
to be applied to all the
elements given by xsimplex
.
Performs the product : X[1,Id[1]]*X[2,Id[2]]*...*X[p,Id[p]] if all the
elements of Id are positive. Otherwise, just return 0.
Value
double : the result of the product.
[Package PhylogeneticEM version 1.7.0 Index]