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Annotation of rpl/lapack/blas/zswap.f, revision 1.2

1.1       bertrand    1:       SUBROUTINE ZSWAP(N,ZX,INCX,ZY,INCY)
                      2: *     .. Scalar Arguments ..
                      3:       INTEGER INCX,INCY,N
                      4: *     ..
                      5: *     .. Array Arguments ..
                      6:       DOUBLE COMPLEX ZX(*),ZY(*)
                      7: *     ..
                      8: *
                      9: *  Purpose
                     10: *  =======
                     11: *
                     12: *     ZSWAP interchanges two vectors.
                     13: *
                     14: *  Further Details
                     15: *  ===============
                     16: *
                     17: *     jack dongarra, 3/11/78.
                     18: *     modified 12/3/93, array(1) declarations changed to array(*)
                     19: *
                     20: *  =====================================================================
                     21: *
                     22: *     .. Local Scalars ..
                     23:       DOUBLE COMPLEX ZTEMP
                     24:       INTEGER I,IX,IY
                     25: *     ..
                     26:       IF (N.LE.0) RETURN
                     27:       IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20
                     28: *
                     29: *       code for unequal increments or equal increments not equal
                     30: *         to 1
                     31: *
                     32:       IX = 1
                     33:       IY = 1
                     34:       IF (INCX.LT.0) IX = (-N+1)*INCX + 1
                     35:       IF (INCY.LT.0) IY = (-N+1)*INCY + 1
                     36:       DO 10 I = 1,N
                     37:           ZTEMP = ZX(IX)
                     38:           ZX(IX) = ZY(IY)
                     39:           ZY(IY) = ZTEMP
                     40:           IX = IX + INCX
                     41:           IY = IY + INCY
                     42:    10 CONTINUE
                     43:       RETURN
                     44: *
                     45: *       code for both increments equal to 1
                     46:    20 DO 30 I = 1,N
                     47:           ZTEMP = ZX(I)
                     48:           ZX(I) = ZY(I)
                     49:           ZY(I) = ZTEMP
                     50:    30 CONTINUE
                     51:       RETURN
                     52:       END