share/fftpack5/fortran/sinqmb.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 SINQMB (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 ('SINQMB', 6)
  22       ELSEIF (LENSAV .LT. 2*N + INT(LOG(REAL(N))/LOG(2.)) +4) THEN
  23         IER = 2
  24         CALL XERFFT ('SINQMB', 8)
  25       ELSEIF (LENWRK .LT. LOT*N) THEN
  26         IER = 3
  27         CALL XERFFT ('SINQMB', 10)
  28       ELSEIF (.NOT. XERCON(INC,JUMP,N,LOT)) THEN
  29         IER = 4
  30         CALL XERFFT ('SINQMB', -1)
  31       ENDIF
  32 C
  33       LJ = (LOT-1)*JUMP+1
  34       IF (N .GT. 1) GO TO 101
  35       DO 201 M=1,LJ,JUMP
  36          X(M,1) = 4.*X(M,1)
  37  201  CONTINUE
  38       RETURN
  39   101 NS2 = N/2
  40       DO 102 K=2,N,2
  41          DO 202 M=1,LJ,JUMP
  42          X(M,K) = -X(M,K)
  43  202     CONTINUE
  44   102 CONTINUE
  45       CALL COSQMB (LOT,JUMP,N,INC,X,LENX,WSAVE,LENSAV,WORK,LENWRK,IER1)
  46       IF (IER1 .NE. 0) THEN
  47         IER = 20
  48         CALL XERFFT ('SINQMB',-5)
  49         GO TO 300
  50       ENDIF
  51       DO 103 K=1,NS2
  52          KC = N-K
  53          DO 203 M=1,LJ,JUMP
  54          XHOLD = X(M,K)
  55          X(M,K) = X(M,KC+1)
  56          X(M,KC+1) = XHOLD
  57  203     CONTINUE
  58   103 CONTINUE
  59   300 CONTINUE
  60       RETURN
  61       END