Move LAPACK trunk into position.

1 files changed, 148 insertions, 0 deletions

diff --git a/SRC/cgetf2.f b/SRC/cgetf2.f
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+      SUBROUTINE CGETF2( M, N, A, LDA, IPIV, INFO )
+*
+*  -- LAPACK routine (version 3.1) --
+*     Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
+*     November 2006
+*
+*     .. Scalar Arguments ..
+      INTEGER            INFO, LDA, M, N
+*     ..
+*     .. Array Arguments ..
+      INTEGER            IPIV( * )
+      COMPLEX            A( LDA, * )
+*     ..
+*
+*  Purpose
+*  =======
+*
+*  CGETF2 computes an 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).
+*
+*  This is the right-looking Level 2 BLAS version of the algorithm.
+*
+*  Arguments
+*  =========
+*
+*  M       (input) INTEGER
+*          The number of rows of the matrix A.  M >= 0.
+*
+*  N       (input) INTEGER
+*          The number of columns of the matrix A.  N >= 0.
+*
+*  A       (input/output) COMPLEX array, dimension (LDA,N)
+*          On entry, the m by n matrix to be factored.
+*          On exit, the factors L and U from the factorization
+*          A = P*L*U; the unit diagonal elements of L are not stored.
+*
+*  LDA     (input) INTEGER
+*          The leading dimension of the array A.  LDA >= max(1,M).
+*
+*  IPIV    (output) INTEGER array, dimension (min(M,N))
+*          The pivot indices; for 1 <= i <= min(M,N), row i of the
+*          matrix was interchanged with row IPIV(i).
+*
+*  INFO    (output) INTEGER
+*          = 0: successful exit
+*          < 0: if INFO = -k, the k-th argument had an illegal value
+*          > 0: if INFO = k, U(k,k) is exactly zero. The factorization
+*               has been completed, but the factor U is exactly
+*               singular, and division by zero will occur if it is used
+*               to solve a system of equations.
+*
+*  =====================================================================
+*
+*     .. Parameters ..
+      COMPLEX            ONE, ZERO
+      PARAMETER          ( ONE = ( 1.0E+0, 0.0E+0 ),
+     $                   ZERO = ( 0.0E+0, 0.0E+0 ) )
+*     ..
+*     .. Local Scalars ..
+      REAL               SFMIN
+      INTEGER            I, J, JP
+*     ..
+*     .. External Functions ..
+      REAL               SLAMCH
+      INTEGER            ICAMAX
+      EXTERNAL           SLAMCH, ICAMAX
+*     ..
+*     .. External Subroutines ..
+      EXTERNAL           CGERU, CSCAL, CSWAP, XERBLA
+*     ..
+*     .. Intrinsic Functions ..
+      INTRINSIC          MAX, MIN
+*     ..
+*     .. Executable Statements ..
+*
+*     Test the input parameters.
+*
+      INFO = 0
+      IF( M.LT.0 ) THEN
+         INFO = -1
+      ELSE IF( N.LT.0 ) THEN
+         INFO = -2
+      ELSE IF( LDA.LT.MAX( 1, M ) ) THEN
+         INFO = -4
+      END IF
+      IF( INFO.NE.0 ) THEN
+         CALL XERBLA( 'CGETF2', -INFO )
+         RETURN
+      END IF
+*
+*     Quick return if possible
+*
+      IF( M.EQ.0 .OR. N.EQ.0 )
+     $   RETURN
+*
+*     Compute machine safe minimum
+*
+      SFMIN = SLAMCH('S') 
+*
+      DO 10 J = 1, MIN( M, N )
+*
+*        Find pivot and test for singularity.
+*
+         JP = J - 1 + ICAMAX( M-J+1, A( J, J ), 1 )
+         IPIV( J ) = JP
+         IF( A( JP, J ).NE.ZERO ) THEN
+*
+*           Apply the interchange to columns 1:N.
+*
+            IF( JP.NE.J )
+     $         CALL CSWAP( N, A( J, 1 ), LDA, A( JP, 1 ), LDA )
+*
+*           Compute elements J+1:M of J-th column.
+*
+            IF( J.LT.M ) THEN
+               IF( ABS(A( J, J )) .GE. SFMIN ) THEN
+                  CALL CSCAL( M-J, ONE / A( J, J ), A( J+1, J ), 1 )
+               ELSE
+                  DO 20 I = 1, M-J
+                     A( J+I, J ) = A( J+I, J ) / A( J, J )
+   20             CONTINUE
+               END IF
+            END IF
+*
+         ELSE IF( INFO.EQ.0 ) THEN
+*
+            INFO = J
+         END IF
+*
+         IF( J.LT.MIN( M, N ) ) THEN
+*
+*           Update trailing submatrix.
+*
+            CALL CGERU( M-J, N-J, -ONE, A( J+1, J ), 1, A( J, J+1 ),
+     $                  LDA, A( J+1, J+1 ), LDA )
+         END IF
+   10 CONTINUE
+      RETURN
+*
+*     End of CGETF2
+*
+      END