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Copy modifications to reorder-related codes from MRST repository

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branches/mrst-reorg/mex/reorder-C, revision 8955.

The changes are: (1) addition of documentation of input arguments in
tarjan.c and (2) an MIT licence header (codes originated in a PhD
project).
This commit is contained in:
Jostein R. Natvig 2012-01-25 10:49:49 +01:00
parent 22d269811f
commit f56c67081d
2 changed files with 114 additions and 40 deletions
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127
opm/core/transport/reorder/tarjan.c
View File

@ -1,4 +1,24 @@
/* Copyright 2011 (c) Jostein R. Natvig <Jostein.R.Natvig at sintef.no> */ /*
Copyright (C) 2012 (c) Jostein R. Natvig <jostein natvig at gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#include <string.h> #include <string.h>
#include <assert.h> #include <assert.h>
@ -14,49 +34,70 @@
static int min(int a, int b){ return a < b? a : b;} static int min(int a, int b){ return a < b? a : b;}
/* Improved (or obfuscated) version uses less memory /*
* Compute the strong components of directed graph G(edges, vertices),
* Use end of P and Q as stack: return components in reverse topological sorted sequence.
* push operation is *s--=elm, Complexity O(|vertices|+|edges|). See "http://en.wikipedia.org/wiki/
* pop operation is elm=*++s, Tarjan's_strongly_connected_components_algorithm".
* peek operation is *(s+1)
nv - number of vertices
ia,ja - adjacency matrix for directed graph in compressed sparse row
format: vertex i has directed edges to vertices ja[ia[i]],
..., ja[ia[i+1]-1].
vert - permutation of vertices into topologically sorted sequence of
strong components (i.e., loops).
comp - pointers to start of each strongly connected component in
vert, the i'th component has vertices vert[comp[i]], ...,
vert[comp[i+1]-1].
ncomp - number of strong components.
work - block of memory of size 3*nv*sizeof(int).
*/ */
/*--------------------------------------------------------------------*/
void void
tarjan (int size, int *ia, int *ja, int *P, int *Q, int *ncomp, tarjan (int nv, const int *ia, const int *ja, int *vert, int *comp,
int *work) int *ncomp, int *work)
/*--------------------------------------------------------------------*/ /*--------------------------------------------------------------------*/
{ {
/* Hint: end of VERT and COMP are used as stacks. */
enum {DONE=-2, REMAINING=-1}; enum {DONE=-2, REMAINING=-1};
int c,v,seed,child; int c, v, seed, child;
int i; int i;
int *stack = Q + size, *bottom = stack; int *stack = comp + nv;
int *cstack = P + size-1, *cbottom = cstack; int *bottom = stack;
int *cstack = vert + nv-1;
int *cbottom = cstack;
int t = 0;
int pos = 0;
int t = 0; int *time = work;
int pos = 0; int *link = (int *) time + nv;
int *status = (int *) link + nv; /* dual usage... */
int *time = work;
int *link = (int *) time + size;
int *status = (int*) link + size; /* dual usage... */
(void) cbottom; (void) cbottom;
memset(work, 0, 3*size * sizeof *work); memset(work, 0, 3*nv * sizeof *work);
memset(P, 0, size * sizeof *P ); memset(vert, 0, nv * sizeof *vert );
memset(Q, 0, (size+1) * sizeof *Q ); memset(comp, 0, (nv+1) * sizeof *comp );
/* Init status all nodes */ /* Init status all vertices */
for (i=0; i<size; ++i) for (i=0; i<nv; ++i)
{ {
status[i] = REMAINING; status[i] = REMAINING;
} }
*ncomp = 0; *ncomp = 0;
*Q++ = pos; *comp++ = pos;
seed = 0; seed = 0;
while (seed < size) while (seed < nv)
{ {
if (status[seed] == DONE) if (status[seed] == DONE)
{ {
@ -64,22 +105,27 @@ tarjan (int size, int *ia, int *ja, int *P, int *Q, int *ncomp,
continue; continue;
} }
*stack-- = seed; /* push seed */ /* push seed */
*stack-- = seed;
t = 0; t = 0;
while ( stack != bottom ) while ( stack != bottom )
{ {
c = *(stack+1); /* peek c */ /* peek c */
c = *(stack+1);
assert(status[c] != DONE); assert(status[c] != DONE);
assert(status[c] >= -2); assert(status[c] >= -2);
if (status[c] == REMAINING) if (status[c] == REMAINING)
{ {
status[c] = ia[c+1]-ia[c]; /* number of descendants of c */ /* number of descendants of c */
status[c] = ia[c+1]-ia[c];
time[c] = link[c] = t++; time[c] = link[c] = t++;
*cstack-- = c; /* push c on strongcomp stack */
/* push c on strongcomp stack */
*cstack-- = c;
} }
@ -95,17 +141,22 @@ tarjan (int size, int *ia, int *ja, int *P, int *Q, int *ncomp,
{ {
assert (cstack != cbottom); assert (cstack != cbottom);
v = *++cstack; /* pop strong component stack */ /* pop strong component stack */
v = *++cstack;
status[v] = DONE; status[v] = DONE;
P[pos++] = v; /* store vertex in P */
/* store vertex in VERT */
vert[pos++] = v;
} }
while ( v != c ); while ( v != c );
*Q++ = pos; /* store end point of component */ /* store end point of component */
*comp++ = pos;
++*ncomp; ++*ncomp;
} }
++stack; /* pop c */ /* pop c */
++stack;
if (stack != bottom) if (stack != bottom)
{ {
@ -121,11 +172,13 @@ tarjan (int size, int *ia, int *ja, int *P, int *Q, int *ncomp,
assert(status[c] > 0); assert(status[c] > 0);
child = ja[ia[c] + status[c]-1]; child = ja[ia[c] + status[c]-1];
--status[c]; /* Decrement descendant count of c*/ /* decrement descendant count of c*/
--status[c];
if (status[child] == REMAINING) if (status[child] == REMAINING)
{ {
*stack-- = child; /* push child */ /* push child */
*stack-- = child;
} }
else if (status[child] >= 0) else if (status[child] >= 0)

27
opm/core/transport/reorder/tarjan.h
View File

@ -1,4 +1,24 @@
/* Copyright 2011 (c) Jostein R. Natvig <Jostein.R.Natvig at sintef.no> */ /*
Copyright (C) 2012 (c) Jostein R. Natvig <jostein natvig at gmail.com>
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/
#ifndef TARJAN_H_INCLUDED #ifndef TARJAN_H_INCLUDED
#define TARJAN_H_INCLUDED #define TARJAN_H_INCLUDED
@ -6,8 +26,9 @@
extern "C" { extern "C" {
#endif #endif
void tarjan (int size, int *ia, int *ja, int *rowP, int *P, void
int *ncomp, int *work); tarjan (int nv, const int *ia, const int *ja, int *vert, int *comp,
int *ncomp, int *work);
#ifdef __cplusplus #ifdef __cplusplus
} }