matrixmaker function

Generate Matrix of One-way Interactions and Squared Terms

Takes a matrix of covariates and generates a new matrix that contains the original covariates, all one-way interaction terms, and all squared terms.

matrixmaker(mat)

Arguments

• mat: n by k numeric matrix of covariates.

Returns

n by (k*(k+1))/2 +1) matrix of covariates with original covariates, all one-way interaction terms, and all squared terms.

Author(s)

Jens Hainmueller

See Also

See getsquares

Examples

# create toy matrix
mold <- replicate(3,rnorm(50))
colnames(mold) <- paste("x",1:3,sep="")
head(mold)
# create new matrix
mnew <- matrixmaker(mold)
head(mnew)