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man pages->IRIX man pages -> complib/dlanv2 (3)
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### Contents

```
DLANV2(3F)							    DLANV2(3F)

```

### NAME[Toc][Back]

```     DLANV2 - compute the Schur	factorization of a real	2-by-2 nonsymmetric
matrix in standard	form
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	DLANV2(	A, B, C, D, RT1R, RT1I,	RT2R, RT2I, CS,	SN )

DOUBLE		PRECISION A, B,	C, CS, D, RT1I,	RT1R, RT2I, RT2R, SN
```

### PURPOSE[Toc][Back]

```     DLANV2 computes the Schur factorization of	a real 2-by-2 nonsymmetric
matrix in standard	form:

[ A  B ] = [ CS -SN ]	[ AA  BB ] [ CS	 SN ]
[ C  D ]   [ SN  CS ]	[ CC  DD ] [-SN	 CS ]

where either
1)	CC = 0 so that AA and DD are real eigenvalues of the matrix, or	2) AA
= DD and BB*CC < 0, so that AA + or - sqrt(BB*CC) are complex conjugate
eigenvalues.

```

### ARGUMENTS[Toc][Back]

```     A	     (input/output) DOUBLE PRECISION
B	     (input/output) DOUBLE PRECISION C	     (input/output)
DOUBLE PRECISION D	      (input/output) DOUBLE PRECISION On
entry, the	elements of the	input matrix.  On exit,	they are
overwritten by the	elements of the	standardised Schur form.

RT1R    (output) DOUBLE PRECISION
RT1I    (output) DOUBLE PRECISION RT2R    (output)	DOUBLE
PRECISION RT2I    (output)	DOUBLE PRECISION The real and
imaginary parts of	the eigenvalues. If the	eigenvalues are	both
real, abs(RT1R) >=	abs(RT2R); if the eigenvalues are a complex
conjugate pair, RT1I > 0.

CS	     (output) DOUBLE PRECISION
SN	     (output) DOUBLE PRECISION Parameters of the rotation
matrix.
DLANV2(3F)							    DLANV2(3F)

```

### NAME[Toc][Back]

```     DLANV2 - compute the Schur	factorization of a real	2-by-2 nonsymmetric
matrix in standard	form
```

### SYNOPSIS[Toc][Back]

```     SUBROUTINE	DLANV2(	A, B, C, D, RT1R, RT1I,	RT2R, RT2I, CS,	SN )

DOUBLE		PRECISION A, B,	C, CS, D, RT1I,	RT1R, RT2I, RT2R, SN
```

### PURPOSE[Toc][Back]

```     DLANV2 computes the Schur factorization of	a real 2-by-2 nonsymmetric
matrix in standard	form:

[ A  B ] = [ CS -SN ]	[ AA  BB ] [ CS	 SN ]
[ C  D ]   [ SN  CS ]	[ CC  DD ] [-SN	 CS ]

where either
1)	CC = 0 so that AA and DD are real eigenvalues of the matrix, or	2) AA
= DD and BB*CC < 0, so that AA + or - sqrt(BB*CC) are complex conjugate
eigenvalues.

```

### ARGUMENTS[Toc][Back]

```     A	     (input/output) DOUBLE PRECISION
B	     (input/output) DOUBLE PRECISION C	     (input/output)
DOUBLE PRECISION D	      (input/output) DOUBLE PRECISION On
entry, the	elements of the	input matrix.  On exit,	they are
overwritten by the	elements of the	standardised Schur form.

RT1R    (output) DOUBLE PRECISION
RT1I    (output) DOUBLE PRECISION RT2R    (output)	DOUBLE
PRECISION RT2I    (output)	DOUBLE PRECISION The real and
imaginary parts of	the eigenvalues. If the	eigenvalues are	both
real, abs(RT1R) >=	abs(RT2R); if the eigenvalues are a complex
conjugate pair, RT1I > 0.

CS	     (output) DOUBLE PRECISION
SN	     (output) DOUBLE PRECISION Parameters of the rotation
matrix.

PPPPaaaaggggeeee 1111```
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