The DETERM function computes the determinant of an n by n array. LU decomposition is used to represent the input array in triangular form. The determinant is then computed as the product of diagonal elements of the triangular form. Row interchanges are tracked during the LU decomposition to ensure the correct sign.
This routine is written in the IDL language. Its source code can be found in the file
subdirectory of the IDL distribution.
Use this keyword to set the absolute value of the floating-point zero. A floating-point zero on the main diagonal of a triangular array results in a zero determinant. For single-precision inputs, the default value is 1.0 ¥ 10 -6 . For double-precision inputs, the default value is 1.0 ¥ 10 -12 . Setting this keyword to a value less than the default may improve the precision of the result.