Description
The
SCOTCH graphBuild
routine fills the source graph structure pointed to
by
grafptr
with all of the data that are passed to it.
baseval
is the graph base value for index arrays (typically 0 for structures
built from C and 1 for structures built from Fortran).
vertnbr
is the number
of vertices.
verttab
is the adjacency index array, of size (
vertnbr
+ 1) if
the edge array is compact (that is, if
vendtab
equals
verttab
+ 1 or
NULL
),
or of size
vertnbr
else.
vendtab
is the adjacency end index array, of size
vertnbr
if it is disjoint from
verttab
.
velotab
is the vertex load array, of
size
vertnbr
if it exists.
vlbltab
is the vertex label array, of size
vertnbr
if
it exists.
edgenbr
is the number of arcs (that is, twice the number of edges).
edgetab
is the adjacency array, of size at least
edgenbr
(it can be more if the
edge array is not compact).
edlotab
is the arc load array, of size
edgenbr
if
it exists.
The
vendtab
,
velotab
,
vlbltab
and
edlotab
arrays are optional, and a
NULL
pointer can be passed as argument whenever they are not defined. Since, in
Fortran, there is no null reference, passing the
scotchfgraphbuild
routine a
reference equal to
verttab
in the
velotab
or
vlbltab
fields makes them be
considered as missing arrays. The same holds for
edlotab
when it is passed a
reference equal to
edgetab
. Setting
vendtab
to refer to one cell after
verttab
yields the same result, as it is the exact semantics of a compact vertex array.
To limit memory consumption,
SCOTCH graphBuild
does not copy array data,
but instead references them in the
SCOTCH Graph
structure. Therefore, great
care should be taken not to modify the contents of the arrays passed to
SCOTCH graphBuild
as long as the graph structure is in use. Every update
of the arrays should be preceded by a call to
SCOTCH graphFree
, to free in-
ternal graph structures, and eventually followed by a new call to
SCOTCH
graphBuild
to re-build these internal structures so as to be able to use the
new graph.
To ensure that inconsistencies in user data do not result in an erroneous behav-
ior of the
libScotch
routines, it is recommended, at least in the development
stage, to call the
SCOTCH graphCheck
routine on the newly created
SCOTCH
Graph
structure before calling any other
libScotch
routine.
Return values
SCOTCH graphBuild
returns 0 if the graph structure has been successfully set
with all of the input data, and 1 else.
7.5.7
SCOTCH graphBase
Synopsis
int SCOTCH graphBase (SCOTCH Graph *
grafptr,
SCOTCH Num
baseval)
scotchfgraphbase (doubleprecision (*)
grafdat,
integer*
num
baseval,
integer*
num
oldbaseval)
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