## Get the product of multiplying each pair of values in a vector (cross-product)

### Description

This function calls a C++ function which multiplies two vectors by each other elementwise, such that the output is of length(a) * length(b).

### Usage

rcpp_mult2probvect(a, b)


### Arguments

 a a numeric vector b a numeric vector

### Details

This is the cross-product operation, which exists in R (%o% or tcrossprod). However, it is handy to have is as a C++ function for calculating the probability of pairs of descendant states, given the probability of each state individually.

### Value

tcross_product_vector the vector which is the product of the convolution

### Author(s)

Nicholas Matzke matzke@berkeley.edu

%o%, tcrossprod, Rcpp_combn_zerostart, rcpp_convolve

### Examples

ca = c(1,2,3,4,5)
cb = c(2,2,2,2,2)
rcpp_mult2probvect(a=ca, b=cb)

# Same as:
c(ca %o% cb)

# Or:
c(outer(ca, cb))

# Or:
tcrossprod(ca, cb)