crossprod {base}R Documentation

Matrix Crossproduct

Description

Given matrices x and y as arguments, crossprod returns their matrix cross-product. This is formally equivalent to, but faster than, the call t(x) %*% y.

Usage

crossprod(x, y = NULL)

Arguments

x, y matrices: y = NULL is taken to be the same matrix as x.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

%*% and outer product %o%.

Examples

(z <- crossprod(1:4))    # = sum(1 + 2^2 + 3^2 + 4^2)
drop(z)                  # scalar

[Package base version 2.1.0 Index]