share/fftpack5/fortran/sint1i.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 SINT1I (N, WSAVE, LENSAV, IER)
  12       INTEGER    N, LENSAV, IER
  13       REAL       WSAVE(LENSAV)
  14 C
  15       IER = 0
  16 C
  17       IF (LENSAV .LT. N/2 + N + INT(LOG(REAL(N))/LOG(2.)) +4) THEN
  18         IER = 2
  19         CALL XERFFT ('SINT1I', 3)
  20         GO TO 300
  21       ENDIF
  22 C
  23       PI = 4.*ATAN(1.)
  24       IF (N .LE. 1) RETURN
  25       NS2 = N/2
  26       NP1 = N+1
  27       DT = PI/FLOAT(NP1)
  28       DO 101 K=1,NS2
  29          WSAVE(K) = 2.*SIN(K*DT)
  30   101 CONTINUE
  31       LNSV = NP1 + INT(LOG(REAL(NP1))/LOG(2.)) +4
  32       CALL RFFT1I (NP1, WSAVE(NS2+1), LNSV, IER1)
  33       IF (IER1 .NE. 0) THEN
  34         IER = 20
  35         CALL XERFFT ('SINT1I',-5)
  36       ENDIF
  37 C
  38   300 CONTINUE
  39       RETURN
  40       END