share/fftpack5/fortran/cosqmf.f

   1 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
   2 C
   3 C   FFTPACK 5.0
   4 C
   5 C   Authors:  Paul N. Swarztrauber and Richard A. Valent
   6 C
   7 C   $Id$
   8 C
   9 CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
  10
  11       SUBROUTINE COSQMF (LOT, JUMP, N, INC, X, LENX, WSAVE, LENSAV,
  12      1                   WORK, LENWRK, IER)
  13       INTEGER    LOT, JUMP, N, INC, LENX, LENSAV, LENWRK, IER
  14       REAL       X(INC,*), WSAVE(LENSAV), WORK(LENWRK)
  15       LOGICAL    XERCON
  16 C
  17       IER = 0
  18 C
  19       IF (LENX .LT. (LOT-1)*JUMP + INC*(N-1) + 1) THEN
  20         IER = 1
  21         CALL XERFFT ('COSQMF', 6)
  22         GO TO 300
  23       ELSEIF (LENSAV .LT. 2*N + INT(LOG(REAL(N))/LOG(2.)) +4) THEN
  24         IER = 2
  25         CALL XERFFT ('COSQMF', 8)
  26         GO TO 300
  27       ELSEIF (LENWRK .LT. LOT*N) THEN
  28         IER = 3
  29         CALL XERFFT ('COSQMF', 10)
  30         GO TO 300
  31       ELSEIF (.NOT. XERCON(INC,JUMP,N,LOT)) THEN
  32         IER = 4
  33         CALL XERFFT ('COSQMF', -1)
  34         GO TO 300
  35       ENDIF
  36 C
  37       LJ = (LOT-1)*JUMP+1
  38       IF (N-2) 102,101,103
  39   101 SSQRT2 = 1./SQRT(2.)
  40       DO 201 M=1,LJ,JUMP
  41       TSQX = SSQRT2*X(M,2)
  42       X(M,2) = .5*X(M,1)-TSQX
  43       X(M,1) = .5*X(M,1)+TSQX
  44   201 CONTINUE
  45   102 RETURN
  46   103 CALL MCSQF1 (LOT,JUMP,N,INC,X,WSAVE,WORK,IER1)
  47       IF (IER1 .NE. 0) THEN
  48         IER = 20
  49         CALL XERFFT ('COSQMF',-5)
  50       ENDIF
  51 C
  52   300 CONTINUE
  53       RETURN
  54       END