Matrix Multiplication

Description

Multiplies two matrices, if they are conformable. If one argument is a vector, it will be coerced to a either a row or column matrix to make the two arguments conformable. If both are vectors it will return the inner product.

Usage

a%*%b

Value

The matrix product. Use drop to get rid of

See Also

matrix, Arithmetic, diag.

Examples

x <- 1:4
x%*%x # scalar ("inner") product (1 x 1 matrix)
drop(.Last.value)# as scalar

y <- diag(x)
z <- matrix(1:12,ncol=3,nrow=4)
y%*%z
y%*%x
x%*%z