LAPACK  3.10.0
LAPACK: Linear Algebra PACKage

◆ caxpy()

subroutine caxpy ( integer  N,
complex  CA,
complex, dimension(*)  CX,
integer  INCX,
complex, dimension(*)  CY,
integer  INCY 
)

CAXPY

Purpose:
    CAXPY constant times a vector plus a vector.
Parameters
[in]N
          N is INTEGER
         number of elements in input vector(s)
[in]CA
          CA is COMPLEX
           On entry, CA specifies the scalar alpha.
[in]CX
          CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
[in]INCX
          INCX is INTEGER
         storage spacing between elements of CX
[in,out]CY
          CY is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCY ) )
[in]INCY
          INCY is INTEGER
         storage spacing between elements of CY
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.
Further Details:
     jack dongarra, linpack, 3/11/78.
     modified 12/3/93, array(1) declarations changed to array(*)

Definition at line 87 of file caxpy.f.

88 *
89 * -- Reference BLAS level1 routine --
90 * -- Reference BLAS is a software package provided by Univ. of Tennessee, --
91 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
92 *
93 * .. Scalar Arguments ..
94  COMPLEX CA
95  INTEGER INCX,INCY,N
96 * ..
97 * .. Array Arguments ..
98  COMPLEX CX(*),CY(*)
99 * ..
100 *
101 * =====================================================================
102 *
103 * .. Local Scalars ..
104  INTEGER I,IX,IY
105 * ..
106 * .. External Functions ..
107  REAL SCABS1
108  EXTERNAL scabs1
109 * ..
110  IF (n.LE.0) RETURN
111  IF (scabs1(ca).EQ.0.0e+0) RETURN
112  IF (incx.EQ.1 .AND. incy.EQ.1) THEN
113 *
114 * code for both increments equal to 1
115 *
116  DO i = 1,n
117  cy(i) = cy(i) + ca*cx(i)
118  END DO
119  ELSE
120 *
121 * code for unequal increments or equal increments
122 * not equal to 1
123 *
124  ix = 1
125  iy = 1
126  IF (incx.LT.0) ix = (-n+1)*incx + 1
127  IF (incy.LT.0) iy = (-n+1)*incy + 1
128  DO i = 1,n
129  cy(iy) = cy(iy) + ca*cx(ix)
130  ix = ix + incx
131  iy = iy + incy
132  END DO
133  END IF
134 *
135  RETURN
136 *
137 * End of CAXPY
138 *
real function scabs1(Z)
SCABS1
Definition: scabs1.f:46