## The routines ludcmp() and lubksb() perform

*LU*decomposition and backsubstitution respectively.## Can easily compute

*A*-1 (solve for the identity matrix column by column) and det(*A*) (find the product of the diagonal elements of the*LU*decomposed matrix) - see NRiC 2.3.__WARNING__: for large matrices, computing det(*A*) can overflow or underflow the computer's floating-point dynamic range.