aux_blas(3) LAPACK aux_blas(3)

aux_blas

# SYNOPSIS¶

## Functions¶

integer function icamax (N, CX, INCX)
ICAMAX integer function idamax (N, DX, INCX)
IDAMAX integer function isamax (N, SX, INCX)
ISAMAX integer function izamax (N, ZX, INCX)
IZAMAX logical function lsame (CA, CB)
LSAME subroutine xerbla (SRNAME, INFO)
XERBLA subroutine xerbla_array (SRNAME_ARRAY, SRNAME_LEN, INFO)
XERBLA_ARRAY

# Detailed Description¶

This is the group of Auxiliary 3 BLAS routines.

# Function Documentation¶

## integer function icamax (integer N, complex, dimension(*) CX, integer INCX)¶

ICAMAX

Purpose:

```    ICAMAX finds the index of the first element having maximum |Re(.)| + |Im(.)|
```

Parameters:

N

```          N is INTEGER
number of elements in input vector(s)
```

CX

```          CX is COMPLEX array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
```

INCX

```          INCX is INTEGER
storage spacing between elements of SX
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

November 2017

Further Details:

```     jack dongarra, linpack, 3/11/78.
modified 3/93 to return if incx .le. 0.
modified 12/3/93, array(1) declarations changed to array(*)
```

## integer function idamax (integer N, double precision, dimension(*) DX, integer INCX)¶

IDAMAX

Purpose:

```    IDAMAX finds the index of the first element having maximum absolute value.
```

Parameters:

N

```          N is INTEGER
number of elements in input vector(s)
```

DX

```          DX is DOUBLE PRECISION array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
```

INCX

```          INCX is INTEGER
storage spacing between elements of SX
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

November 2017

Further Details:

```     jack dongarra, linpack, 3/11/78.
modified 3/93 to return if incx .le. 0.
modified 12/3/93, array(1) declarations changed to array(*)
```

## integer function isamax (integer N, real, dimension(*) SX, integer INCX)¶

ISAMAX

Purpose:

```    ISAMAX finds the index of the first element having maximum absolute value.
```

Parameters:

N

```          N is INTEGER
number of elements in input vector(s)
```

SX

```          SX is REAL array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
```

INCX

```          INCX is INTEGER
storage spacing between elements of SX
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

November 2017

Further Details:

```     jack dongarra, linpack, 3/11/78.
modified 3/93 to return if incx .le. 0.
modified 12/3/93, array(1) declarations changed to array(*)
```

## integer function izamax (integer N, complex*16, dimension(*) ZX, integer INCX)¶

IZAMAX

Purpose:

```    IZAMAX finds the index of the first element having maximum |Re(.)| + |Im(.)|
```

Parameters:

N

```          N is INTEGER
number of elements in input vector(s)
```

ZX

```          ZX is COMPLEX*16 array, dimension ( 1 + ( N - 1 )*abs( INCX ) )
```

INCX

```          INCX is INTEGER
storage spacing between elements of SX
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

November 2017

Further Details:

```     jack dongarra, 1/15/85.
modified 3/93 to return if incx .le. 0.
modified 12/3/93, array(1) declarations changed to array(*)
```

## logical function lsame (character CA, character CB)¶

LSAME

Purpose:

``` LSAME returns .TRUE. if CA is the same letter as CB regardless of
case.
```

Parameters:

CA

```          CA is CHARACTER*1
```

CB

```          CB is CHARACTER*1
CA and CB specify the single characters to be compared.
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

December 2016

## subroutine xerbla (character*(*) SRNAME, integer INFO)¶

XERBLA

Purpose:

``` XERBLA  is an error handler for the LAPACK routines.
It is called by an LAPACK routine if an input parameter has an
invalid value.  A message is printed and execution stops.
Installers may consider modifying the STOP statement in order to
call system-specific exception-handling facilities.
```

Parameters:

SRNAME

```          SRNAME is CHARACTER*(*)
The name of the routine which called XERBLA.
```

INFO

```          INFO is INTEGER
The position of the invalid parameter in the parameter list
of the calling routine.
```

Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

December 2016

## subroutine xerbla_array (character(1), dimension(srname_len) SRNAME_ARRAY, integer SRNAME_LEN, integer INFO)¶

XERBLA_ARRAY

Purpose:

``` XERBLA_ARRAY assists other languages in calling XERBLA, the LAPACK
and BLAS error handler.  Rather than taking a Fortran string argument
as the function's name, XERBLA_ARRAY takes an array of single
characters along with the array's length.  XERBLA_ARRAY then copies
up to 32 characters of that array into a Fortran string and passes
that to XERBLA.  If called with a non-positive SRNAME_LEN,
XERBLA_ARRAY will call XERBLA with a string of all blank characters.
Say some macro or other device makes XERBLA_ARRAY available to C99
by a name lapack_xerbla and with a common Fortran calling convention.
Then a C99 program could invoke XERBLA via:
{
int flen = strlen(__func__);
lapack_xerbla(__func__, &flen, &info);
}
Providing XERBLA_ARRAY is not necessary for intercepting LAPACK
errors.  XERBLA_ARRAY calls XERBLA.
```

Parameters:

SRNAME_ARRAY

```          SRNAME_ARRAY is CHARACTER(1) array, dimension (SRNAME_LEN)
The name of the routine which called XERBLA_ARRAY.
```

SRNAME_LEN

```          SRNAME_LEN is INTEGER
The length of the name in SRNAME_ARRAY.
```

INFO

```          INFO is INTEGER
The position of the invalid parameter in the parameter list
of the calling routine.
```

Author:

Univ. of Tennessee

Univ. of California Berkeley