00001 SUBROUTINE CLACRT( N, CX, INCX, CY, INCY, C, S ) 00002 * 00003 * -- LAPACK auxiliary routine (version 3.2) -- 00004 * -- LAPACK is a software package provided by Univ. of Tennessee, -- 00005 * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 00006 * November 2006 00007 * 00008 * .. Scalar Arguments .. 00009 INTEGER INCX, INCY, N 00010 COMPLEX C, S 00011 * .. 00012 * .. Array Arguments .. 00013 COMPLEX CX( * ), CY( * ) 00014 * .. 00015 * 00016 * Purpose 00017 * ======= 00018 * 00019 * CLACRT performs the operation 00020 * 00021 * ( c s )( x ) ==> ( x ) 00022 * ( -s c )( y ) ( y ) 00023 * 00024 * where c and s are complex and the vectors x and y are complex. 00025 * 00026 * Arguments 00027 * ========= 00028 * 00029 * N (input) INTEGER 00030 * The number of elements in the vectors CX and CY. 00031 * 00032 * CX (input/output) COMPLEX array, dimension (N) 00033 * On input, the vector x. 00034 * On output, CX is overwritten with c*x + s*y. 00035 * 00036 * INCX (input) INTEGER 00037 * The increment between successive values of CX. INCX <> 0. 00038 * 00039 * CY (input/output) COMPLEX array, dimension (N) 00040 * On input, the vector y. 00041 * On output, CY is overwritten with -s*x + c*y. 00042 * 00043 * INCY (input) INTEGER 00044 * The increment between successive values of CY. INCY <> 0. 00045 * 00046 * C (input) COMPLEX 00047 * S (input) COMPLEX 00048 * C and S define the matrix 00049 * [ C S ]. 00050 * [ -S C ] 00051 * 00052 * ===================================================================== 00053 * 00054 * .. Local Scalars .. 00055 INTEGER I, IX, IY 00056 COMPLEX CTEMP 00057 * .. 00058 * .. Executable Statements .. 00059 * 00060 IF( N.LE.0 ) 00061 $ RETURN 00062 IF( INCX.EQ.1 .AND. INCY.EQ.1 ) 00063 $ GO TO 20 00064 * 00065 * Code for unequal increments or equal increments not equal to 1 00066 * 00067 IX = 1 00068 IY = 1 00069 IF( INCX.LT.0 ) 00070 $ IX = ( -N+1 )*INCX + 1 00071 IF( INCY.LT.0 ) 00072 $ IY = ( -N+1 )*INCY + 1 00073 DO 10 I = 1, N 00074 CTEMP = C*CX( IX ) + S*CY( IY ) 00075 CY( IY ) = C*CY( IY ) - S*CX( IX ) 00076 CX( IX ) = CTEMP 00077 IX = IX + INCX 00078 IY = IY + INCY 00079 10 CONTINUE 00080 RETURN 00081 * 00082 * Code for both increments equal to 1 00083 * 00084 20 CONTINUE 00085 DO 30 I = 1, N 00086 CTEMP = C*CX( I ) + S*CY( I ) 00087 CY( I ) = C*CY( I ) - S*CX( I ) 00088 CX( I ) = CTEMP 00089 30 CONTINUE 00090 RETURN 00091 END
1.7.2