| 1 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
|---|
| 2 | ! |
|---|
| 3 | ! FFTPACK 5.0 |
|---|
| 4 | ! Copyright (C) 1995-2004, Scientific Computing Division, |
|---|
| 5 | ! University Corporation for Atmospheric Research |
|---|
| 6 | ! Licensed under the GNU General Public License (GPL) |
|---|
| 7 | ! |
|---|
| 8 | ! Authors: Paul N. Swarztrauber and Richard A. Valent |
|---|
| 9 | ! |
|---|
| 10 | ! $Id: cosq1f.f,v 1.3 2004/06/15 21:14:57 rodney Exp $ |
|---|
| 11 | ! |
|---|
| 12 | !CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC |
|---|
| 13 | |
|---|
| 14 | SUBROUTINE COSQ1F (N, INC, X, LENX, WSAVE, LENSAV, & |
|---|
| 15 | & WORK, LENWRK, IER) |
|---|
| 16 | INTEGER N, INC, LENX, LENSAV, LENWRK, IER |
|---|
| 17 | REAL X(INC,*), WSAVE(LENSAV), WORK(LENWRK) |
|---|
| 18 | ! |
|---|
| 19 | IER = 0 |
|---|
| 20 | ! |
|---|
| 21 | IF (LENX .LT. INC*(N-1) + 1) THEN |
|---|
| 22 | IER = 1 |
|---|
| 23 | CALL XERFFT ('COSQ1F', 6) |
|---|
| 24 | GO TO 300 |
|---|
| 25 | ELSEIF (LENSAV .LT. 2*N + INT(LOG(REAL(N))) +4) THEN |
|---|
| 26 | IER = 2 |
|---|
| 27 | CALL XERFFT ('COSQ1F', 8) |
|---|
| 28 | GO TO 300 |
|---|
| 29 | ELSEIF (LENWRK .LT. N) THEN |
|---|
| 30 | IER = 3 |
|---|
| 31 | CALL XERFFT ('COSQ1F', 10) |
|---|
| 32 | GO TO 300 |
|---|
| 33 | ENDIF |
|---|
| 34 | ! |
|---|
| 35 | IF (N-2) 102,101,103 |
|---|
| 36 | 101 SSQRT2 = 1./SQRT(2.) |
|---|
| 37 | TSQX = SSQRT2*X(1,2) |
|---|
| 38 | X(1,2) = .5*X(1,1)-TSQX |
|---|
| 39 | X(1,1) = .5*X(1,1)+TSQX |
|---|
| 40 | 102 RETURN |
|---|
| 41 | 103 CALL COSQF1 (N,INC,X,WSAVE,WORK,IER1) |
|---|
| 42 | IF (IER1 .NE. 0) THEN |
|---|
| 43 | IER = 20 |
|---|
| 44 | CALL XERFFT ('COSQ1F',-5) |
|---|
| 45 | ENDIF |
|---|
| 46 | ! |
|---|
| 47 | 300 CONTINUE |
|---|
| 48 | RETURN |
|---|
| 49 | END |
|---|
