Visible to Intel only — GUID: GUID-00347F6B-7F5A-46B7-93DA-AF6905A84432
Visible to Intel only — GUID: GUID-00347F6B-7F5A-46B7-93DA-AF6905A84432
?getf2
Computes the LU factorization of a general m-by-n matrix using partial pivoting with row interchanges (unblocked algorithm).
Syntax
call sgetf2( m, n, a, lda, ipiv, info )
call dgetf2( m, n, a, lda, ipiv, info )
call cgetf2( m, n, a, lda, ipiv, info )
call zgetf2( m, n, a, lda, ipiv, info )
Include Files
- mkl.fi
Description
The routine computes the LU factorization of a general m-by-n matrix A using partial pivoting with row interchanges. The factorization has the form
A = P*L*U
where p is a permutation matrix, L is lower triangular with unit diagonal elements (lower trapezoidal if m > n) and U is upper triangular (upper trapezoidal if m < n).
Input Parameters
The data types are given for the Fortran interface.
- m
-
INTEGER. The number of rows in the matrix A (m≥ 0).
- n
-
INTEGER. The number of columns in A (n≥ 0).
- a
-
REAL for sgetf2
DOUBLE PRECISION for dgetf2
COMPLEX for cgetf2
DOUBLE COMPLEX for zgetf2.
Array, size (lda,*). Contains the matrix A to be factored. The second dimension of a must be at least max(1, n).
- lda
-
INTEGER. The leading dimension of a; at least max(1, m).
Output Parameters
- a
-
Overwritten by L and U. The unit diagonal elements of L are not stored.
- ipiv
-
INTEGER.
Array, size at least max(1,min(m,n)).
The pivot indices: for 1 ≤ i ≤ n, row i was interchanged with row ipiv(i).
- info
-
INTEGER. If info=0, the execution is successful.
If info = -i, the i-th parameter had an illegal value.
If info = i >0, uii is 0. The factorization has been completed, but U is exactly singular. Division by 0 will occur if you use the factor U for solving a system of linear equations.
If info = -1011, memory allocation error occurred.