The absolute value of the largest element in U . If a pivot element is less than this number, the matrix is reported as singular. Any computed element whose absolute value is less than this number is set to 0. Its size is specified by naux . You have the option of having the minimum required value for naux dynamically returned to your program.
L is a unit lower triangular matrix.
U is an upper triangular matrix. P is a permutation matrix. Q is a permutation matrix. If n is 0, no computation is performed. If this subroutine has to perform storage compressions, an attention message is issued.