It must be 'U' or 'L'. Otherwise, it is the storage work area used by this subroutine. Its size is specified by naux . The work area is deallocated before control is returned to the calling program. On Return ap is the resulting array, referred to as AP , containing the inverse of the matrix in lower-packed storage mode.
All subroutines accept lowercase letters for the uplo argument.
In your C program, argument rcond must be passed by reference. You have the option of having the minimum required value for naux dynamically returned to your program. If n is 0, no computation is performed. Unable to allocate internal work area. Computational Errors Matrix A is not positive definite.