# crot.f

Section: LAPACK (3)
Updated: Tue Nov 14 2017
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crot.f

## SYNOPSIS

### Functions/Subroutines

subroutine crot (N, CX, INCX, CY, INCY, C, S)
CROT applies a plane rotation with real cosine and complex sine to a pair of complex vectors.

## Function/Subroutine Documentation

### subroutine crot (integer N, complex, dimension( * ) CX, integer INCX, complex, dimension( * ) CY, integer INCY, real C, complex S)

CROT applies a plane rotation with real cosine and complex sine to a pair of complex vectors.

Purpose:

``` CROT   applies a plane rotation, where the cos (C) is real and the
sin (S) is complex, and the vectors CX and CY are complex.
```

Parameters:

N

```          N is INTEGER
The number of elements in the vectors CX and CY.
```

CX

```          CX is COMPLEX array, dimension (N)
On input, the vector X.
On output, CX is overwritten with C*X + S*Y.
```

INCX

```          INCX is INTEGER
The increment between successive values of CY.  INCX <> 0.
```

CY

```          CY is COMPLEX array, dimension (N)
On input, the vector Y.
On output, CY is overwritten with -CONJG(S)*X + C*Y.
```

INCY

```          INCY is INTEGER
The increment between successive values of CY.  INCX <> 0.
```

C

```          C is REAL
```

S

```          S is COMPLEX
C and S define a rotation
[  C          S  ]
[ -conjg(S)   C  ]
where C*C + S*CONJG(S) = 1.0.
```

Author:

Univ. of Tennessee

Univ. of California Berkeley