share/fftpack5/fortran/cosqmi.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 COSQMI (N, WSAVE, LENSAV, IER)
  12       INTEGER    N, LENSAV, IER
  13       REAL       WSAVE(LENSAV)
  14 C
  15       IER = 0
  16 C
  17       IF (LENSAV .LT. 2*N + INT(LOG(REAL(N))/LOG(2.)) +4) THEN
  18         IER = 2
  19         CALL XERFFT ('COSQMI', 3)
  20         GO TO 300
  21       ENDIF
  22 C
  23       PIH = 2.*ATAN(1.)
  24       DT = PIH/FLOAT(N)
  25       FK = 0.
  26       DO 101 K=1,N
  27          FK = FK+1.
  28          WSAVE(K) = COS(FK*DT)
  29   101 CONTINUE
  30       LNSV = N + INT(LOG(REAL(N))/LOG(2.)) +4
  31       CALL RFFTMI (N, WSAVE(N+1), LNSV, IER1)
  32       IF (IER1 .NE. 0) THEN
  33         IER = 20
  34         CALL XERFFT ('COSQMI',-5)
  35       ENDIF
  36   300 CONTINUE
  37       RETURN
  38       END