01:       SUBROUTINE ZLACRT( N, CX, INCX, CY, INCY, C, S )
02: *
03: *  -- LAPACK auxiliary routine (version 3.2) --
04: *  -- LAPACK is a software package provided by Univ. of Tennessee,    --
05: *  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
06: *     November 2006
07: *
08: *     .. Scalar Arguments ..
09:       INTEGER            INCX, INCY, N
10:       COMPLEX*16         C, S
11: *     ..
12: *     .. Array Arguments ..
13:       COMPLEX*16         CX( * ), CY( * )
14: *     ..
15: *
16: *  Purpose
17: *  =======
18: *
19: *  ZLACRT performs the operation
20: *
21: *     (  c  s )( x )  ==> ( x )
22: *     ( -s  c )( y )      ( y )
23: *
24: *  where c and s are complex and the vectors x and y are complex.
25: *
26: *  Arguments
27: *  =========
28: *
29: *  N       (input) INTEGER
30: *          The number of elements in the vectors CX and CY.
31: *
32: *  CX      (input/output) COMPLEX*16 array, dimension (N)
33: *          On input, the vector x.
34: *          On output, CX is overwritten with c*x + s*y.
35: *
36: *  INCX    (input) INTEGER
37: *          The increment between successive values of CX.  INCX <> 0.
38: *
39: *  CY      (input/output) COMPLEX*16 array, dimension (N)
40: *          On input, the vector y.
41: *          On output, CY is overwritten with -s*x + c*y.
42: *
43: *  INCY    (input) INTEGER
44: *          The increment between successive values of CY.  INCY <> 0.
45: *
46: *  C       (input) COMPLEX*16
47: *  S       (input) COMPLEX*16
48: *          C and S define the matrix
49: *             [  C   S  ].
50: *             [ -S   C  ]
51: *
52: * =====================================================================
53: *
54: *     .. Local Scalars ..
55:       INTEGER            I, IX, IY
56:       COMPLEX*16         CTEMP
57: *     ..
58: *     .. Executable Statements ..
59: *
60:       IF( N.LE.0 )
61:      $   RETURN
62:       IF( INCX.EQ.1 .AND. INCY.EQ.1 )
63:      $   GO TO 20
64: *
65: *     Code for unequal increments or equal increments not equal to 1
66: *
67:       IX = 1
68:       IY = 1
69:       IF( INCX.LT.0 )
70:      $   IX = ( -N+1 )*INCX + 1
71:       IF( INCY.LT.0 )
72:      $   IY = ( -N+1 )*INCY + 1
73:       DO 10 I = 1, N
74:          CTEMP = C*CX( IX ) + S*CY( IY )
75:          CY( IY ) = C*CY( IY ) - S*CX( IX )
76:          CX( IX ) = CTEMP
77:          IX = IX + INCX
78:          IY = IY + INCY
79:    10 CONTINUE
80:       RETURN
81: *
82: *     Code for both increments equal to 1
83: *
84:    20 CONTINUE
85:       DO 30 I = 1, N
86:          CTEMP = C*CX( I ) + S*CY( I )
87:          CY( I ) = C*CY( I ) - S*CX( I )
88:          CX( I ) = CTEMP
89:    30 CONTINUE
90:       RETURN
91:       END
92: