 LAPACK 3.11.0 LAPACK: Linear Algebra PACKage
Searching...
No Matches

## ◆ cswap()

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

CSWAP

Purpose:
`   CSWAP interchanges two vectors.`
Parameters
 [in] N ``` N is INTEGER number of elements in input vector(s)``` [in,out] 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```
Further Details:
```     jack dongarra, linpack, 3/11/78.
modified 12/3/93, array(1) declarations changed to array(*)```

Definition at line 80 of file cswap.f.

81*
82* -- Reference BLAS level1 routine --
83* -- Reference BLAS is a software package provided by Univ. of Tennessee, --
84* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
85*
86* .. Scalar Arguments ..
87 INTEGER INCX,INCY,N
88* ..
89* .. Array Arguments ..
90 COMPLEX CX(*),CY(*)
91* ..
92*
93* =====================================================================
94*
95* .. Local Scalars ..
96 COMPLEX CTEMP
97 INTEGER I,IX,IY
98* ..
99 IF (n.LE.0) RETURN
100 IF (incx.EQ.1 .AND. incy.EQ.1) THEN
101*
102* code for both increments equal to 1
103 DO i = 1,n
104 ctemp = cx(i)
105 cx(i) = cy(i)
106 cy(i) = ctemp
107 END DO
108 ELSE
109*
110* code for unequal increments or equal increments not equal
111* to 1
112*
113 ix = 1
114 iy = 1
115 IF (incx.LT.0) ix = (-n+1)*incx + 1
116 IF (incy.LT.0) iy = (-n+1)*incy + 1
117 DO i = 1,n
118 ctemp = cx(ix)
119 cx(ix) = cy(iy)
120 cy(iy) = ctemp
121 ix = ix + incx
122 iy = iy + incy
123 END DO
124 END IF
125 RETURN
126*
127* End of CSWAP
128*