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SUBROUTINE SLAPMT( FORWRD, M, N, X, LDX, K )
*
* -- LAPACK auxiliary routine (version 3.1) --
* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
* November 2006
*
* .. Scalar Arguments ..
LOGICAL FORWRD
INTEGER LDX, M, N
* ..
* .. Array Arguments ..
INTEGER K( * )
REAL X( LDX, * )
* ..
*
* 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.
*
* Arguments
* =========
*
* FORWRD (input) LOGICAL
* = .TRUE., forward permutation
* = .FALSE., backward permutation
*
* M (input) INTEGER
* The number of rows of the matrix X. M >= 0.
*
* N (input) INTEGER
* The number of columns of the matrix X. N >= 0.
*
* X (input/output) REAL array, dimension (LDX,N)
* On entry, the M by N matrix X.
* On exit, X contains the permuted matrix X.
*
* LDX (input) INTEGER
* The leading dimension of the array X, LDX >= MAX(1,M).
*
* K (input/output) 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.
*
* =====================================================================
*
* .. 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
*
END
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