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Tue, Feb 18, 23:37
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rLAMMPS lammps
drscl.f
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*>
\
brief
\
b
DRSCL
multiplies
a
vector
by
the
reciprocal
of
a
real
scalar
.
*
*
===========
DOCUMENTATION
===========
*
*
Online
html
documentation
available
at
*
http
:
//
www
.
netlib
.
org
/
lapack
/
explore
-
html
/
*
*>
\
htmlonly
*>
Download
DRSCL
+
dependencies
*>
<
a
href
=
"http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/drscl.f"
>
*>
[
TGZ
]
</
a
>
*>
<
a
href
=
"http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/drscl.f"
>
*>
[
ZIP
]
</
a
>
*>
<
a
href
=
"http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/drscl.f"
>
*>
[
TXT
]
</
a
>
*>
\
endhtmlonly
*
*
Definition
:
*
===========
*
*
SUBROUTINE
DRSCL
(
N
,
SA
,
SX
,
INCX
)
*
*
..
Scalar
Arguments
..
*
INTEGER
INCX
,
N
*
DOUBLE PRECISION
SA
*
..
*
..
Array
Arguments
..
*
DOUBLE PRECISION
SX
(
*
)
*
..
*
*
*>
\
par
Purpose
:
*
=============
*>
*>
\
verbatim
*>
*>
DRSCL
multiplies
an
n
-
element
real
vector
x
by
the
real
scalar
1
/
a
.
*>
This
is
done
without
overflow
or
underflow
as
long
as
*>
the
final
result
x
/
a
does
not
overflow
or
underflow
.
*>
\
endverbatim
*
*
Arguments
:
*
==========
*
*>
\
param
[
in
]
N
*>
\
verbatim
*>
N
is
INTEGER
*>
The
number
of
components
of
the
vector
x
.
*>
\
endverbatim
*>
*>
\
param
[
in
]
SA
*>
\
verbatim
*>
SA
is
DOUBLE PRECISION
*>
The
scalar
a
which
is
used
to
divide
each
component
of
x
.
*>
SA
must
be
>=
0
,
or
the
subroutine
will
divide
by
zero
.
*>
\
endverbatim
*>
*>
\
param
[
in
,
out
]
SX
*>
\
verbatim
*>
SX
is
DOUBLE PRECISION
array
,
dimension
*>
(
1
+
(
N
-
1
)
*
abs
(
INCX
))
*>
The
n
-
element
vector
x
.
*>
\
endverbatim
*>
*>
\
param
[
in
]
INCX
*>
\
verbatim
*>
INCX
is
INTEGER
*>
The
increment
between
successive
values
of
the
vector
SX
.
*>
>
0
:
SX
(
1
)
=
X
(
1
)
and
SX
(
1
+
(
i
-
1
)
*
INCX
)
=
x
(
i
),
1
<
i
<=
n
*>
\
endverbatim
*
*
Authors
:
*
========
*
*>
\
author
Univ
.
of
Tennessee
*>
\
author
Univ
.
of
California
Berkeley
*>
\
author
Univ
.
of
Colorado
Denver
*>
\
author
NAG
Ltd
.
*
*>
\
date
September
2012
*
*>
\
ingroup
doubleOTHERauxiliary
*
*
=====================================================================
SUBROUTINE
DRSCL
(
N
,
SA
,
SX
,
INCX
)
*
*
--
LAPACK
auxiliary
routine
(
version
3.4.2
)
--
*
--
LAPACK
is
a
software
package
provided
by
Univ
.
of
Tennessee
,
--
*
--
Univ
.
of
California
Berkeley
,
Univ
.
of
Colorado
Denver
and
NAG
Ltd
..
--
*
September
2012
*
*
..
Scalar
Arguments
..
INTEGER
INCX
,
N
DOUBLE PRECISION
SA
*
..
*
..
Array
Arguments
..
DOUBLE PRECISION
SX
(
*
)
*
..
*
*
=====================================================================
*
*
..
Parameters
..
DOUBLE PRECISION
ONE
,
ZERO
PARAMETER
(
ONE
=
1.0
D
+
0
,
ZERO
=
0.0
D
+
0
)
*
..
*
..
Local
Scalars
..
LOGICAL
DONE
DOUBLE PRECISION
BIGNUM
,
CDEN
,
CDEN1
,
CNUM
,
CNUM1
,
MUL
,
SMLNUM
*
..
*
..
External
Functions
..
DOUBLE PRECISION
DLAMCH
EXTERNAL
DLAMCH
*
..
*
..
External
Subroutines
..
EXTERNAL
DSCAL
*
..
*
..
Intrinsic
Functions
..
INTRINSIC
ABS
*
..
*
..
Executable
Statements
..
*
*
Quick
return if
possible
*
IF
(
N
.LE.
0
)
$
RETURN
*
*
Get
machine
parameters
*
SMLNUM
=
DLAMCH
(
'S'
)
BIGNUM
=
ONE
/
SMLNUM
CALL
DLABAD
(
SMLNUM
,
BIGNUM
)
*
*
Initialize
the
denominator
to
SA
and
the
numerator
to
1.
*
CDEN
=
SA
CNUM
=
ONE
*
10
CONTINUE
CDEN1
=
CDEN
*
SMLNUM
CNUM1
=
CNUM
/
BIGNUM
IF
(
ABS
(
CDEN1
)
.GT.
ABS
(
CNUM
)
.AND.
CNUM
.NE.
ZERO
)
THEN
*
*
Pre
-
multiply
X
by
SMLNUM
if
CDEN
is
large
compared
to
CNUM
.
*
MUL
=
SMLNUM
DONE
=
.FALSE.
CDEN
=
CDEN1
ELSE IF
(
ABS
(
CNUM1
)
.GT.
ABS
(
CDEN
)
)
THEN
*
*
Pre
-
multiply
X
by
BIGNUM
if
CDEN
is
small
compared
to
CNUM
.
*
MUL
=
BIGNUM
DONE
=
.FALSE.
CNUM
=
CNUM1
ELSE
*
*
Multiply
X
by
CNUM
/
CDEN
and
return
.
*
MUL
=
CNUM
/
CDEN
DONE
=
.TRUE.
END IF
*
*
Scale
the
vector
X
by
MUL
*
CALL
DSCAL
(
N
,
MUL
,
SX
,
INCX
)
*
IF
(
.NOT.
DONE
)
$
GO
TO
10
*
RETURN
*
*
End
of
DRSCL
*
END
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