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dperm

  1. C DPERM     SOURCE    CHAT      05/01/12    22:54:41     5004
  2.       SUBROUTINE DPERM (NROW,A,JA,IA,AO,JAO,IAO,PERM,QPERM,JOB)
  3.       IMPLICIT INTEGER(I-N)
  4.       IMPLICIT REAL*8 (A-H,O-Z)
  5. C***********************************************************************
  6. C NOM         : DPERM
  7. C DESCRIPTION : Permutation (lignes et colonnes) d'une matrice Morse.
  8. C
  9. C
  10. C LANGAGE     : FORTRAN 77
  11. C ADAPTATION  :  Stéphane GOUNAND (CEA/DRN/DMT/SEMT/LTMF)
  12. C                mél : gounand@semt2.smts.cea.fr
  13. C AUTEUR      :
  14. C  Sparskit : a basic tool kit for sparse matrix computations
  15. C  Version 2 (Youcef Saad)
  16. C  -> URL : http://www.cs.umn.edu/Research/arpa/SPARSKIT/sparskit.html
  17. C
  18. C***********************************************************************
  19.       INTEGER NROW,JA(*),IA(NROW+1),JAO(*),IAO(NROW+1),PERM(NROW),
  20.      +        QPERM(*),JOB
  21.       REAL*8 A(*),AO(*)
  22. c-----------------------------------------------------------------------
  23. c This routine permutes the rows and columns of a matrix stored in CSR
  24. c format. i.e., it computes P A Q, where P, Q are permutation matrices.
  25. c P maps row i into row perm(i) and Q maps column j into column qperm(j):
  26. c      a(i,j)    becomes   a(perm(i),qperm(j)) in new matrix
  27. c In the particular case where Q is the transpose of P (symmetric
  28. c permutation of A) then qperm is not needed.
  29. c note that qperm should be of length ncol (number of columns) but this
  30. c is not checked.
  31. c-----------------------------------------------------------------------
  32. c Y. Saad, Sep. 21 1989 / recoded Jan. 28 1991.
  33. c-----------------------------------------------------------------------
  34. c on entry:
  35. c----------
  36. c n     = dimension of the matrix
  37. c a, ja,
  38. c    ia = input matrix in a, ja, ia format
  39. c perm  = integer array of length n containing the permutation arrays
  40. c         for the rows: perm(i) is the destination of row i in the
  41. c         permuted matrix -- also the destination of column i in case
  42. c         permutation is symmetric (job .le. 2)
  43. c
  44. c qperm = same thing for the columns. This should be provided only
  45. c         if job=3 or job=4, i.e., only in the case of a nonsymmetric
  46. c         permutation of rows and columns. Otherwise qperm is a dummy
  47. c
  48. c job   = integer indicating the work to be done:
  49. c * job = 1,2 permutation is symmetric  Ao :== P * A * transp(P)
  50. c               job = 1 permute a, ja, ia into ao, jao, iao
  51. c               job = 2 permute matrix ignoring real values.
  52. c * job = 3,4 permutation is non-symmetric  Ao :== P * A * Q
  53. c               job = 3 permute a, ja, ia into ao, jao, iao
  54. c               job = 4 permute matrix ignoring real values.
  55. c
  56. c on return:
  57. c-----------
  58. c ao, jao, iao = input matrix in a, ja, ia format
  59. c
  60. c in case job .eq. 2 or job .eq. 4, a and ao are never referred to
  61. c and can be dummy arguments.
  62. c Notes:
  63. c-------
  64. c  1) algorithm is in place (Faux ! vu que RPERM ne l'est pas)
  65. c  2) column indices may not be sorted on return even  though they may be
  66. c     on entry.
  67. c----------------------------------------------------------------------c
  68. c local variables
  69.       INTEGER LOCJOB, MOD
  70. c
  71. c     locjob indicates whether or not real values must be copied.
  72. c
  73.       LOCJOB = MOD(JOB,2)
  74. c
  75. c permute rows first
  76. c
  77.       CALL RPERM (NROW,A,JA,IA,AO,JAO,IAO,PERM,LOCJOB)
  78. c
  79. c then permute columns
  80. c
  81.       LOCJOB = 0
  82. c
  83.       IF (JOB .LE. 2) THEN
  84.          CALL CPERM (NROW,AO,JAO,IAO,AO,JAO,IAO,PERM,LOCJOB)
  85.       ELSE
  86.          CALL CPERM (NROW,AO,JAO,IAO,AO,JAO,IAO,QPERM,LOCJOB)
  87.       ENDIF
  88. c
  89.       RETURN
  90. c-------end-of-dperm----------------------------------------------------
  91. c-----------------------------------------------------------------------
  92.       END
  93.  
  94.  
  95.  

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