subroutine slapmt	(	logical	FORWRD,
		integer	M,
		integer	N,
		real, dimension( ldx, * )	X,
		integer	LDX,
		integer, dimension( * )	K
	)

SLAPMT performs a forward or backward permutation of the columns of a matrix.

Download SLAPMT + dependencies [TGZ] [ZIP] [TXT]

Purpose:

 SLAPMT rearranges the columns of the M by N matrix X as specified
 by the permutation K(1),K(2),...,K(N) of the integers 1,...,N.
 If FORWRD = .TRUE.,  forward permutation:

      X(*,K(J)) is moved X(*,J) for J = 1,2,...,N.

 If FORWRD = .FALSE., backward permutation:

      X(*,J) is moved to X(*,K(J)) for J = 1,2,...,N.

Parameters

[in]	FORWRD	FORWRD is LOGICAL = .TRUE., forward permutation = .FALSE., backward permutation
[in]	M	M is INTEGER The number of rows of the matrix X. M >= 0.
[in]	N	N is INTEGER The number of columns of the matrix X. N >= 0.
[in,out]	X	X is REAL array, dimension (LDX,N) On entry, the M by N matrix X. On exit, X contains the permuted matrix X.
[in]	LDX	LDX is INTEGER The leading dimension of the array X, LDX >= MAX(1,M).
[in,out]	K	K is INTEGER array, dimension (N) On entry, K contains the permutation vector. K is used as internal workspace, but reset to its original value on output.

Author

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

Date

September 2012

Definition at line 106 of file slapmt.f.

*
*  -- LAPACK auxiliary routine (version 3.4.2) --
*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
*     September 2012
*
*     .. Scalar Arguments ..
      LOGICAL            forwrd
      INTEGER            ldx, m, n
*     ..
*     .. Array Arguments ..
      INTEGER            k( * )
      REAL               x( ldx, * )
*     ..
*
*  =====================================================================
*
*     .. Local Scalars ..
      INTEGER            i, ii, j, in
      REAL               temp
*     ..
*     .. Executable Statements ..
*
      IF( n.LE.1 )
     $   RETURN
*
      DO 10 i = 1, n
         k( i ) = -k( i )
   10 CONTINUE
*
      IF( forwrd ) THEN
*
*        Forward permutation
*
         DO 60 i = 1, n
*
            IF( k( i ).GT.0 )
     $         GO TO 40
*
            j = i
            k( j ) = -k( j )
            in = k( j )
*
   20       CONTINUE
            IF( k( in ).GT.0 )
     $         GO TO 40
*
            DO 30 ii = 1, m
               temp = x( ii, j )
               x( ii, j ) = x( ii, in )
               x( ii, in ) = temp
   30       CONTINUE
*
            k( in ) = -k( in )
            j = in
            in = k( in )
            GO TO 20
*
   40       CONTINUE
*
   60    CONTINUE
*
      ELSE
*
*        Backward permutation
*
         DO 110 i = 1, n
*
            IF( k( i ).GT.0 )
     $         GO TO 100
*
            k( i ) = -k( i )
            j = k( i )
   80       CONTINUE
            IF( j.EQ.i )
     $         GO TO 100
*
            DO 90 ii = 1, m
               temp = x( ii, i )
               x( ii, i ) = x( ii, j )
               x( ii, j ) = temp
   90       CONTINUE
*
            k( j ) = -k( j )
            j = k( j )
            GO TO 80
*
  100       CONTINUE

  110    CONTINUE
*
      END IF
*
      RETURN
*
*     End of SLAPMT
*

Here is the caller graph for this function: