Mercurial > octave
comparison libcruft/blas/sswap.f @ 7789:82be108cc558
First attempt at single precision tyeps
* * *
corrections to qrupdate single precision routines
* * *
prefer demotion to single over promotion to double
* * *
Add single precision support to log2 function
* * *
Trivial PROJECT file update
* * *
Cache optimized hermitian/transpose methods
* * *
Add tests for tranpose/hermitian and ChangeLog entry for new transpose code
| author | David Bateman <dbateman@free.fr> |
|---|---|
| date | Sun, 27 Apr 2008 22:34:17 +0200 |
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| children |
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| 7788:45f5faba05a2 | 7789:82be108cc558 |
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| 1 SUBROUTINE SSWAP(N,SX,INCX,SY,INCY) | |
| 2 * .. Scalar Arguments .. | |
| 3 INTEGER INCX,INCY,N | |
| 4 * .. | |
| 5 * .. Array Arguments .. | |
| 6 REAL SX(*),SY(*) | |
| 7 * .. | |
| 8 * | |
| 9 * Purpose | |
| 10 * ======= | |
| 11 * | |
| 12 * interchanges two vectors. | |
| 13 * uses unrolled loops for increments equal to 1. | |
| 14 * jack dongarra, linpack, 3/11/78. | |
| 15 * modified 12/3/93, array(1) declarations changed to array(*) | |
| 16 * | |
| 17 * | |
| 18 * .. Local Scalars .. | |
| 19 REAL STEMP | |
| 20 INTEGER I,IX,IY,M,MP1 | |
| 21 * .. | |
| 22 * .. Intrinsic Functions .. | |
| 23 INTRINSIC MOD | |
| 24 * .. | |
| 25 IF (N.LE.0) RETURN | |
| 26 IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20 | |
| 27 * | |
| 28 * code for unequal increments or equal increments not equal | |
| 29 * to 1 | |
| 30 * | |
| 31 IX = 1 | |
| 32 IY = 1 | |
| 33 IF (INCX.LT.0) IX = (-N+1)*INCX + 1 | |
| 34 IF (INCY.LT.0) IY = (-N+1)*INCY + 1 | |
| 35 DO 10 I = 1,N | |
| 36 STEMP = SX(IX) | |
| 37 SX(IX) = SY(IY) | |
| 38 SY(IY) = STEMP | |
| 39 IX = IX + INCX | |
| 40 IY = IY + INCY | |
| 41 10 CONTINUE | |
| 42 RETURN | |
| 43 * | |
| 44 * code for both increments equal to 1 | |
| 45 * | |
| 46 * | |
| 47 * clean-up loop | |
| 48 * | |
| 49 20 M = MOD(N,3) | |
| 50 IF (M.EQ.0) GO TO 40 | |
| 51 DO 30 I = 1,M | |
| 52 STEMP = SX(I) | |
| 53 SX(I) = SY(I) | |
| 54 SY(I) = STEMP | |
| 55 30 CONTINUE | |
| 56 IF (N.LT.3) RETURN | |
| 57 40 MP1 = M + 1 | |
| 58 DO 50 I = MP1,N,3 | |
| 59 STEMP = SX(I) | |
| 60 SX(I) = SY(I) | |
| 61 SY(I) = STEMP | |
| 62 STEMP = SX(I+1) | |
| 63 SX(I+1) = SY(I+1) | |
| 64 SY(I+1) = STEMP | |
| 65 STEMP = SX(I+2) | |
| 66 SX(I+2) = SY(I+2) | |
| 67 SY(I+2) = STEMP | |
| 68 50 CONTINUE | |
| 69 RETURN | |
| 70 END |