share/fftpack5/fortran/cfft1b.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 CFFT1B (N, INC, C, LENC, WSAVE, LENSAV,
  12      1                  WORK, LENWRK, IER)
  13       INTEGER  N, INC, LENC, LENSAV, LENWRK, IER
  14       COMPLEX       C(LENC)
  15       REAL     WSAVE(LENSAV)     ,WORK(LENWRK)
  16 C
  17       IER = 0
  18 C
  19       IF (LENC .LT. INC*(N-1) + 1) THEN
  20         IER = 1
  21         CALL XERFFT ('CFFT1B ', 4)
  22       ELSEIF (LENSAV .LT. 2*N + INT(LOG(REAL(N))/LOG(2.)) + 4) THEN
  23         IER = 2
  24         CALL XERFFT ('CFFT1B ', 6)
  25       ELSEIF (LENWRK .LT. 2*N) THEN
  26         IER = 3
  27         CALL XERFFT ('CFFT1B ', 8)
  28       ENDIF
  29 C
  30       IF (N .EQ. 1) RETURN
  31 C
  32       IW1 = N+N+1
  33       CALL C1FM1B (N,INC,C,WORK,WSAVE,WSAVE(IW1),
  34      1                           WSAVE(IW1+1))
  35       RETURN
  36       END