SUBROUTINE CSROT( N, CX, INCX, CY, INCY, C, S )
    INTEGER INCX, INCY, N
    REAL C, S
    COMPLEX CX( * ), CY( * )
    INTEGER I, IX, IY
    COMPLEX CTEMP
    IF( N.LE.0 ) RETURN
    IF( INCX.EQ.1 .AND. INCY.EQ.1 ) GO TO 20
    IX = 1
    IY = 1
    IF( INCX.LT.0 ) IX = ( ‐N+1 )*INCX + 1
    IF( INCY.LT.0 ) IY = ( ‐N+1 )*INCY + 1
    DO 10 I = 1, N
    CTEMP = C*CX( IX ) + S*CY( IY )
    CY( IY ) = C*CY( IY ) ‐ S*CX( IX )
    CX( IX ) = CTEMP
    IX = IX + INCX
    IY = IY + INCY
    10 CONTINUE
    RETURN
    20 DO 30 I = 1, N
    CTEMP = C*CX( I ) + S*CY( I )
    CY( I ) = C*CY( I ) ‐ S*CX( I )
    CX( I ) = CTEMP
    30 CONTINUE
    RETURN
    END

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