Annotation of rpl/lapack/blas/zaxpy.f, revision 1.7
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
1.7 ! bertrand 32: IF (INCX.EQ.1 .AND. INCY.EQ.1) THEN
! 33: *
! 34: * code for both increments equal to 1
! 35: *
! 36: DO I = 1,N
! 37: ZY(I) = ZY(I) + ZA*ZX(I)
! 38: END DO
! 39: ELSE
1.1 bertrand 40: *
41: * code for unequal increments or equal increments
42: * not equal to 1
43: *
1.7 ! bertrand 44: IX = 1
! 45: IY = 1
! 46: IF (INCX.LT.0) IX = (-N+1)*INCX + 1
! 47: IF (INCY.LT.0) IY = (-N+1)*INCY + 1
! 48: DO I = 1,N
! 49: ZY(IY) = ZY(IY) + ZA*ZX(IX)
! 50: IX = IX + INCX
! 51: IY = IY + INCY
! 52: END DO
! 53: END IF
1.1 bertrand 54: *
55: RETURN
56: END
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