rmatrix-inverse

How to check if a matrix has an inverse in the R language

How do you determine if a matrix has an inverse in R?

So is there in R a function that with a matrix input, will return somethin like:

"TRUE" (this matrix has inverse)/"FALSE"(it hasn't ...).

Solution

  • @MAB has a good point. This uses solve(...) to decide if the matrix is invertible.

    f <- function(m) class(try(solve(m),silent=T))=="matrix"
x <- matrix(rep(1,25),nc=5)          # singular
y <- matrix(1+1e-10*rnorm(25),nc=5)  # very nearly singular matrix
z <- 0.001*diag(1,5)                 # non-singular, but very smalll determinant
f(x)
# [1] FALSE
f(y)
# [1] TRUE
f(z)
# [1] TRUE