Matrix determinant

Syntax: | `a = DET(m)`

The function `DET(m)` returns the determinant of the matrix `m`, which must be a square matrix. The output is a scalar.

Beware: The determinant of a reasonably sized matrix can get very large, or very small, leading to over/underflows.

The method used to find the determinant uses the LU decomposition of the matrix argument. Please refer to the discussion on LU decomposition of a matrix in the `INVERSE` function section.