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 CX```

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 DX```

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 ZX```

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