share/fftpack5/fortran/cosqmb.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 COSQMB (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 ('COSQMB', 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 ('COSQMB', 8)
  26         GO TO 300
  27       ELSEIF (LENWRK .LT. LOT*N) THEN
  28         IER = 3
  29         CALL XERFFT ('COSQMB', 10)
  30         GO TO 300
  31       ELSEIF (.NOT. XERCON(INC,JUMP,N,LOT)) THEN
  32         IER = 4
  33         CALL XERFFT ('COSQMB', -1)
  34         GO TO 300
  35       ENDIF
  36 C
  37       LJ = (LOT-1)*JUMP+1
  38       IF (N-2) 101,102,103
  39  101  DO 201 M=1,LJ,JUMP
  40       X(M,1) = X(M,1)
  41  201  CONTINUE
  42       RETURN
  43  102  SSQRT2 = 1./SQRT(2.)
  44       DO 202 M=1,LJ,JUMP
  45       X1 = X(M,1)+X(M,2)
  46       X(M,2) = SSQRT2*(X(M,1)-X(M,2))
  47       X(M,1) = X1
  48  202  CONTINUE
  49       RETURN
  50   103 CALL MCSQB1 (LOT,JUMP,N,INC,X,WSAVE,WORK,IER1)
  51       IF (IER1 .NE. 0) THEN
  52         IER = 20
  53         CALL XERFFT ('COSQMB',-5)
  54       ENDIF
  55 C
  56   300 CONTINUE
  57       RETURN
  58       END