Applies a plane rotation.
BLAS Library (libblas.a)
SUBROUTINE SROT(N,X,INCX,Y,INCY,C,S)
INTEGER INCX, INCY, N
REAL C, S
REAL X(*), Y(*)
SUBROUTINE DROT(N,X,INCX,Y,INCY,C,S)
INTEGER INCX,INCY,N
DOUBLE PRECISION C,S
DOUBLE PRECISION X(*),Y(*)
SUBROUTINE CSROT(N,X,INCX,Y,INCY,C,S)
INTEGER INCX,INCY,N
REAL C,S
COMPLEX X(*),Y(*)
SUBROUTINE ZDROT(N,X,INCX,Y,INCY,C,S)
INTEGER INCX,INCY,N
DOUBLE PRECISION C,S
COMPLEX*16 X(*),Y(*)
The SROT, DROT, CSROT, or ZDROT subroutine computes:
--- --- --- --- --- ---
| X | | C S | | X |
| i | | | | i |
| | := | | . | | for i = 1, ..., N.
| Y | | | | Y |
| i | | -S C | | i |
--- --- --- --- --- ---
The subroutines return the modified X and Y.
Item | Description |
---|---|
N | On entry, N specifies the number of elements in X and Y; unchanged on exit. |
X | Vector of dimension at least (1 + (N-1) * abs (INCX) ); unchanged on exit. |
INCX | On entry, INCX specifies the increment for the elements of X; unchanged on exit. |
Y | Vector of dimension at least (1 + (N-1) * abs(INCY) ); modified on exit. |
INCY | On entry, INCY specifies the increment for the elements of Y; unchanged on exit. |
C | Scalar constant; unchanged on exit. |
S | Scalar constant; unchanged on exit. |
If N <= 0, or if C = 1 and S = 0, the subroutines return immediately.