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Annotation of rpl/lapack/blas/zaxpy.f, revision 1.5

1.1       bertrand    1:       SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
                      2: *     .. Scalar Arguments ..
                      3:       DOUBLE COMPLEX ZA
                      4:       INTEGER INCX,INCY,N
                      5: *     ..
                      6: *     .. Array Arguments ..
                      7:       DOUBLE COMPLEX ZX(*),ZY(*)
                      8: *     ..
                      9: *
                     10: *  Purpose
                     11: *  =======
                     12: *
                     13: *     ZAXPY constant times a vector plus a vector.
                     14: *
                     15: *  Further Details
                     16: *  ===============
                     17: *
                     18: *     jack dongarra, 3/11/78.
                     19: *     modified 12/3/93, array(1) declarations changed to array(*)
                     20: *
                     21: *  =====================================================================
                     22: *
                     23: *     .. Local Scalars ..
                     24:       INTEGER I,IX,IY
                     25: *     ..
                     26: *     .. External Functions ..
                     27:       DOUBLE PRECISION DCABS1
                     28:       EXTERNAL DCABS1
                     29: *     ..
                     30:       IF (N.LE.0) RETURN
                     31:       IF (DCABS1(ZA).EQ.0.0d0) RETURN
                     32:       IF (INCX.EQ.1 .AND. INCY.EQ.1) GO TO 20
                     33: *
                     34: *        code for unequal increments or equal increments
                     35: *          not equal to 1
                     36: *
                     37:       IX = 1
                     38:       IY = 1
                     39:       IF (INCX.LT.0) IX = (-N+1)*INCX + 1
                     40:       IF (INCY.LT.0) IY = (-N+1)*INCY + 1
                     41:       DO 10 I = 1,N
                     42:           ZY(IY) = ZY(IY) + ZA*ZX(IX)
                     43:           IX = IX + INCX
                     44:           IY = IY + INCY
                     45:    10 CONTINUE
                     46:       RETURN
                     47: *
                     48: *        code for both increments equal to 1
                     49: *
                     50:    20 DO 30 I = 1,N
                     51:           ZY(I) = ZY(I) + ZA*ZX(I)
                     52:    30 CONTINUE
                     53:       RETURN
                     54:       END