# ?rot

Performs rotation of points in the plane.

## Syntax

FORTRAN 77:

call srot( n, x, incx, y, incy, c, s )

call drot( n, x, incx, y, incy, c, s )

call csrot( n, x, incx, y, incy, c, s )

call zdrot( n, x, incx, y, incy, c, s )

Fortran 95:

call rot(x, y [,c] [,s])

## Description

Given two complex vectors x and y, each vector element of these vectors is replaced as follows:
`x(i) = c*x(i) + s*y(i)`
`y(i) = c*y(i) - s*x(i)`

## Input Parameters

n

  INTEGER. Specifies the number of elements in vectors x and y.

x

  REAL for srot

  DOUBLE PRECISION for drot

  COMPLEX for csrot

  DOUBLE COMPLEX for zdrot

  Array, DIMENSION at least `(1 + (n-1)*abs(incx))`.

incx

  INTEGER. Specifies the increment for the elements of x.

y

  REAL for srot

  DOUBLE PRECISION for drot

  COMPLEX for csrot

  DOUBLE COMPLEX for zdrot

  Array, DIMENSION at least `(1 + (n -1)*abs(incy))`.

incy

  INTEGER. Specifies the increment for the elements of y.

c

  REAL for srot

  DOUBLE PRECISION for drot

  REAL for csrot

  DOUBLE PRECISION for zdrot

  A scalar.

s

  REAL for srot

  DOUBLE PRECISION for drot

  REAL for csrot

  DOUBLE PRECISION for zdrot

  A scalar.

## Output Parameters

x

  Each element is replaced by `c*x + s*y`.

y

  Each element is replaced by c*y - s*x.

## Fortran 95 Interface Notes

Routines in Fortran 95 interface have fewer arguments in the calling sequence than their FORTRAN 77 counterparts. For general conventions applied to skip redundant or reconstructible arguments, see Fortran 95 Interface Conventions.

Specific details for the routine rot interface are the following:

x

  Holds the vector of length(n).

y

  Holds the vector of length (n).

c

  The default value is 1.

s

  The default value is 1.

Parent topic: BLAS Level 1 Routines