# clargv.f

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

## SYNOPSIS

### Functions/Subroutines

subroutine clargv (N, X, INCX, Y, INCY, C, INCC)
CLARGV generates a vector of plane rotations with real cosines and complex sines.

## Function/Subroutine Documentation

### subroutine clargv (integer N, complex, dimension( * ) X, integer INCX, complex, dimension( * ) Y, integer INCY, real, dimension( * ) C, integer INCC)

CLARGV generates a vector of plane rotations with real cosines and complex sines.

Purpose:

``` CLARGV generates a vector of complex plane rotations with real
cosines, determined by elements of the complex vectors x and y.
For i = 1,2,...,n

(        c(i)   s(i) ) ( x(i) ) = ( r(i) )
( -conjg(s(i))  c(i) ) ( y(i) ) = (   0  )

where c(i)**2 + ABS(s(i))**2 = 1

The following conventions are used (these are the same as in CLARTG,
but differ from the BLAS1 routine CROTG):
If y(i)=0, then c(i)=1 and s(i)=0.
If x(i)=0, then c(i)=0 and s(i) is chosen so that r(i) is real.
```

Parameters:

N

```          N is INTEGER
The number of plane rotations to be generated.
```

X

```          X is COMPLEX array, dimension (1+(N-1)*INCX)
On entry, the vector x.
On exit, x(i) is overwritten by r(i), for i = 1,...,n.
```

INCX

```          INCX is INTEGER
The increment between elements of X. INCX > 0.
```

Y

```          Y is COMPLEX array, dimension (1+(N-1)*INCY)
On entry, the vector y.
On exit, the sines of the plane rotations.
```

INCY

```          INCY is INTEGER
The increment between elements of Y. INCY > 0.
```

C

```          C is REAL array, dimension (1+(N-1)*INCC)
The cosines of the plane rotations.
```

INCC

```          INCC is INTEGER
The increment between elements of C. INCC > 0.
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

December 2016

Further Details:

```  6-6-96 - Modified with a new algorithm by W. Kahan and J. Demmel

This version has a few statements commented out for thread safety
(machine parameters are computed on each entry). 10 feb 03, SJH.
```

Definition at line 124 of file clargv.f.

## Author

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