121 lines
3.2 KiB
Fortran
121 lines
3.2 KiB
Fortran
SUBROUTINE CLASWPF( N, A, LDA, K1, K2, IPIV, INCX )
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*
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* -- LAPACK auxiliary routine (version 3.0) --
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* Univ. of Tennessee, Univ. of California Berkeley, NAG Ltd.,
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* Courant Institute, Argonne National Lab, and Rice University
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* June 30, 1999
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*
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* .. Scalar Arguments ..
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INTEGER INCX, K1, K2, LDA, N
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* ..
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* .. Array Arguments ..
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INTEGER IPIV( * )
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COMPLEX A( LDA, * )
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* ..
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*
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* Purpose
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* =======
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*
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* CLASWP performs a series of row interchanges on the matrix A.
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* One row interchange is initiated for each of rows K1 through K2 of A.
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*
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* Arguments
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* =========
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*
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* N (input) INTEGER
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* The number of columns of the matrix A.
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*
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* A (input/output) COMPLEX array, dimension (LDA,N)
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* On entry, the matrix of column dimension N to which the row
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* interchanges will be applied.
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* On exit, the permuted matrix.
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*
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* LDA (input) INTEGER
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* The leading dimension of the array A.
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*
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* K1 (input) INTEGER
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* The first element of IPIV for which a row interchange will
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* be done.
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*
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* K2 (input) INTEGER
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* The last element of IPIV for which a row interchange will
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* be done.
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*
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* IPIV (input) INTEGER array, dimension (M*abs(INCX))
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* The vector of pivot indices. Only the elements in positions
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* K1 through K2 of IPIV are accessed.
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* IPIV(K) = L implies rows K and L are to be interchanged.
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*
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* INCX (input) INTEGER
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* The increment between successive values of IPIV. If IPIV
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* is negative, the pivots are applied in reverse order.
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*
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* Further Details
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* ===============
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*
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* Modified by
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* R. C. Whaley, Computer Science Dept., Univ. of Tenn., Knoxville, USA
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*
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* =====================================================================
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*
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* .. Local Scalars ..
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INTEGER I, I1, I2, INC, IP, IX, IX0, J, K, N32
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COMPLEX TEMP
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* ..
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* .. Executable Statements ..
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*
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* Interchange row I with row IPIV(I) for each of rows K1 through K2.
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*
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IF( INCX.GT.0 ) THEN
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IX0 = K1
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I1 = K1
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I2 = K2
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INC = 1
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ELSE IF( INCX.LT.0 ) THEN
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IX0 = 1 + ( 1-K2 )*INCX
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I1 = K2
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I2 = K1
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INC = -1
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ELSE
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RETURN
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END IF
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*
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N32 = ( N / 32 )*32
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IF( N32.NE.0 ) THEN
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DO 30 J = 1, N32, 32
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IX = IX0
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DO 20 I = I1, I2, INC
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IP = IPIV( IX )
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IF( IP.NE.I ) THEN
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DO 10 K = J, J + 31
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TEMP = A( I, K )
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A( I, K ) = A( IP, K )
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A( IP, K ) = TEMP
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10 CONTINUE
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END IF
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IX = IX + INCX
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20 CONTINUE
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30 CONTINUE
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END IF
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IF( N32.NE.N ) THEN
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N32 = N32 + 1
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IX = IX0
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DO 50 I = I1, I2, INC
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IP = IPIV( IX )
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IF( IP.NE.I ) THEN
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DO 40 K = N32, N
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TEMP = A( I, K )
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A( I, K ) = A( IP, K )
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A( IP, K ) = TEMP
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40 CONTINUE
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END IF
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IX = IX + INCX
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50 CONTINUE
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END IF
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*
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RETURN
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*
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* End of CLASWP
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*
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END
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