Annotation of rpl/lapack/blas/zaxpy.f, revision 1.8
1.8 ! bertrand 1: *> \brief \b ZAXPY
! 2: *
! 3: * =========== DOCUMENTATION ===========
! 4: *
! 5: * Online html documentation available at
! 6: * http://www.netlib.org/lapack/explore-html/
! 7: *
! 8: * Definition:
! 9: * ===========
! 10: *
! 11: * SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
! 12: *
! 13: * .. Scalar Arguments ..
! 14: * COMPLEX*16 ZA
! 15: * INTEGER INCX,INCY,N
! 16: * ..
! 17: * .. Array Arguments ..
! 18: * COMPLEX*16 ZX(*),ZY(*)
! 19: * ..
! 20: *
! 21: *
! 22: *> \par Purpose:
! 23: * =============
! 24: *>
! 25: *> \verbatim
! 26: *>
! 27: *> ZAXPY constant times a vector plus a vector.
! 28: *> \endverbatim
! 29: *
! 30: * Authors:
! 31: * ========
! 32: *
! 33: *> \author Univ. of Tennessee
! 34: *> \author Univ. of California Berkeley
! 35: *> \author Univ. of Colorado Denver
! 36: *> \author NAG Ltd.
! 37: *
! 38: *> \date November 2011
! 39: *
! 40: *> \ingroup complex16_blas_level1
! 41: *
! 42: *> \par Further Details:
! 43: * =====================
! 44: *>
! 45: *> \verbatim
! 46: *>
! 47: *> jack dongarra, 3/11/78.
! 48: *> modified 12/3/93, array(1) declarations changed to array(*)
! 49: *> \endverbatim
! 50: *>
! 51: * =====================================================================
1.1 bertrand 52: SUBROUTINE ZAXPY(N,ZA,ZX,INCX,ZY,INCY)
1.8 ! bertrand 53: *
! 54: * -- Reference BLAS level1 routine (version 3.4.0) --
! 55: * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
! 56: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
! 57: * November 2011
! 58: *
1.1 bertrand 59: * .. Scalar Arguments ..
1.8 ! bertrand 60: COMPLEX*16 ZA
1.1 bertrand 61: INTEGER INCX,INCY,N
62: * ..
63: * .. Array Arguments ..
1.8 ! bertrand 64: COMPLEX*16 ZX(*),ZY(*)
1.1 bertrand 65: * ..
66: *
67: * =====================================================================
68: *
69: * .. Local Scalars ..
70: INTEGER I,IX,IY
71: * ..
72: * .. External Functions ..
73: DOUBLE PRECISION DCABS1
74: EXTERNAL DCABS1
75: * ..
76: IF (N.LE.0) RETURN
77: IF (DCABS1(ZA).EQ.0.0d0) RETURN
1.7 bertrand 78: IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
79: *
80: * code for both increments equal to 1
81: *
82: DO I = 1,N
83: ZY(I) = ZY(I) + ZA*ZX(I)
84: END DO
85: ELSE
1.1 bertrand 86: *
87: * code for unequal increments or equal increments
88: * not equal to 1
89: *
1.7 bertrand 90: IX = 1
91: IY = 1
92: IF (INCX.LT.0) IX = (-N+1)*INCX + 1
93: IF (INCY.LT.0) IY = (-N+1)*INCY + 1
94: DO I = 1,N
95: ZY(IY) = ZY(IY) + ZA*ZX(IX)
96: IX = IX + INCX
97: IY = IY + INCY
98: END DO
99: END IF
1.1 bertrand 100: *
101: RETURN
102: END
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