You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
100 lines
4.5 KiB
Fortran
100 lines
4.5 KiB
Fortran
C
|
|
C Parallel Sparse BLAS v2.0
|
|
C (C) Copyright 2006 Salvatore Filippone University of Rome Tor Vergata
|
|
C Alfredo Buttari University of Rome Tor Vergata
|
|
C
|
|
C Redistribution and use in source and binary forms, with or without
|
|
C modification, are permitted provided that the following conditions
|
|
C are met:
|
|
C 1. Redistributions of source code must retain the above copyright
|
|
C notice, this list of conditions and the following disclaimer.
|
|
C 2. Redistributions in binary form must reproduce the above copyright
|
|
C notice, this list of conditions, and the following disclaimer in the
|
|
C documentation and/or other materials provided with the distribution.
|
|
C 3. The name of the PSBLAS group or the names of its contributors may
|
|
C not be used to endorse or promote products derived from this
|
|
C software without specific written permission.
|
|
C
|
|
C THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
C ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
C TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
C PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
|
|
C BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
C CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
C SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
C INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
C CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
C ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
C POSSIBILITY OF SUCH DAMAGE.
|
|
C
|
|
C
|
|
***********************************************************************
|
|
* *
|
|
* REFERENCES = *
|
|
* *
|
|
* [1] D. E. Knuth *
|
|
* The art of computer programming Vol. 1 *
|
|
* Sect. 1.3.3 *
|
|
* Addison-Wesley *
|
|
* *
|
|
* *
|
|
* FUNCTION: Checks whether a vector really is a permutation *
|
|
* works by exploiting the cycle structure of the *
|
|
* permutation. *
|
|
* *
|
|
* *
|
|
***********************************************************************
|
|
LOGICAL FUNCTION ISAPERM(N,IP)
|
|
C .. Scalar Arguments ..
|
|
INTEGER N
|
|
C ..
|
|
C .. Array Arguments ..
|
|
INTEGER IP(N)
|
|
C ..
|
|
C .. Local Scalars ..
|
|
INTEGER I,J,M
|
|
C ..
|
|
|
|
ISAPERM = .TRUE.
|
|
C
|
|
C Sanity check first
|
|
C
|
|
DO I=1, N
|
|
IF ((IP(I).LT.1).OR.(IP(I).GT.N)) THEN
|
|
ISAPERM = .FALSE.
|
|
RETURN
|
|
ENDIF
|
|
ENDDO
|
|
|
|
C
|
|
C Now work through the cycles, by marking each successive item as negative.
|
|
C No cycle should intersect with any other, hence the .GE.1 check.
|
|
C
|
|
DO M = 1, N
|
|
I = IP(M)
|
|
IF (I.LT.0) THEN
|
|
IP(M) = -I
|
|
ELSE IF (I.NE.M) THEN
|
|
J = IP(I)
|
|
IP(I) = -J
|
|
I = J
|
|
DO WHILE ((J.GE.1).AND.(J.NE.M))
|
|
J = IP(I)
|
|
IP(I) = -J
|
|
I = J
|
|
ENDDO
|
|
IP(M) = IABS(IP(M))
|
|
IF (J.NE.M) THEN
|
|
ISAPERM = .FALSE.
|
|
DO I=1, N
|
|
IP(I) = IABS(IP(I))
|
|
ENDDO
|
|
GOTO 9999
|
|
ENDIF
|
|
END IF
|
|
ENDDO
|
|
9999 CONTINUE
|
|
|
|
RETURN
|
|
END
|