 LAPACK  3.10.1 LAPACK: Linear Algebra PACKage

## ◆ 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 *