# clartg.f man page

clartg.f —

## Synopsis

### Functions/Subroutines

subroutineclartg(F, G, CS, SN, R)CLARTGgenerates a plane rotation with real cosine and complex sine.

## Function/Subroutine Documentation

### subroutine clartg (complexF, complexG, realCS, complexSN, complexR)

**CLARTG** generates a plane rotation with real cosine and complex sine.

**Purpose:**

```
CLARTG generates a plane rotation so that
[ CS SN ] [ F ] [ R ]
[ __ ] . [ ] = [ ] where CS**2 + |SN|**2 = 1.
[ -SN CS ] [ G ] [ 0 ]
This is a faster version of the BLAS1 routine CROTG, except for
the following differences:
F and G are unchanged on return.
If G=0, then CS=1 and SN=0.
If F=0, then CS=0 and SN is chosen so that R is real.
```

**Parameters:**

*F*

```
F is COMPLEX
The first component of vector to be rotated.
```

*G*

```
G is COMPLEX
The second component of vector to be rotated.
```

*CS*

```
CS is REAL
The cosine of the rotation.
```

*SN*

```
SN is COMPLEX
The sine of the rotation.
```

*R*

```
R is COMPLEX
The nonzero component of the rotated vector.
```

**Author:**

Univ. of Tennessee

Univ. of California Berkeley

Univ. of Colorado Denver

NAG Ltd.

**Date:**

November 2013

**Further Details:**

```
3-5-96 - 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 104 of file clartg.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

clartg(3) is an alias of clartg.f(3).

Sat Nov 16 2013 Version 3.4.2 LAPACK