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Prim.cpp
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Prim.cpp
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#include <iostream>
#include <thread>
#include <mutex>
#include <chrono>
#include <cstdio>
#include "Prim.h"
#include "FibHeap.h"
#ifdef WITH_GUI
#include "interface.h"
void syncGUI(int signal, unsigned u, unsigned v)
{
unsigned char sp;
runMode m;
shared_mtx.lock();
sp = speed;
m = mode;
shared_mtx.unlock();
if (m == RUN)
std::this_thread::sleep_for(std::chrono::milliseconds(MILLISEC / sp));
/* GUI update request */
if (u == UINT_MAX)
sigEvent(signal); /* update the whole scene */
else if (v == UINT_MAX)
sigEvent(signal, u); /* update only minimal node */
else
sigEvent(signal, u, v); /* update MST */
/* wait for GUI ready */
std::unique_lock<std::mutex> u_lock(uni_mtx);
while (!ready)
cv.wait(u_lock);
/* continue with execution of the next hunk */
ready = false;
}
#endif
using namespace std;
int
Prim::PrimMinSpanningTree(int (*weight)(unsigned u, unsigned v),
unsigned root)
{
#ifdef WITH_GUI
unsigned line;
unsigned tmp_line[2];
GET_LINE(line);
#endif
int ret = -1;
int w = -1;
unsigned i = 0;
FibNodePtr u = nullptr;
FibNodePtr v = nullptr;
vector<FibNodePtr> pi(this->adj.size(), NULL); // predecessor array
if (!this->adj.size()) {
throw PrimException(fmtError("failed to find minimum spanning tree:"
" no vertices given"));
goto cleanup;
}
if (!this->edges.size()) {
throw PrimException(fmtError("failed to find minimum spanning tree:"
" no edges given"));
goto cleanup;
}
if (root >= this->adj.size() || !this->adj[root][0]) {
char buf[100];
sprintf(buf,"failed to minimum spannig tree: root '%d' does not"
" exist", root);
throw PrimException(fmtError(buf));
goto cleanup;
}
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
tmp_line[0] = line;
#endif
/* properly initialize Fibonacci heap */
for (i = 0; i < this->adj.size(); i++) {
#ifdef WITH_GUI
line = tmp_line[0];
NEXT_LINE(line);
syncGUI(SIG_NEXT_LINE);
#endif
if (!this->adj[i][0])
continue;
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
this->adj[i][0]->key = INT_MAX;
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_PRIM_STEP_FINISHED);
syncGUI(SIG_NEXT_LINE);
#endif
pi[this->adj[i][0]->id] = NULL;
#ifdef WITH_GUI // finished Fibonacci init
syncGUI(SIG_PRIM_STEP_FINISHED);
#endif
}
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
/* r.key = 0 */
this->adj[root][0]->key = 0;
#ifdef WITH_GUI // finished root init
NEXT_LINE(++line);
syncGUI(SIG_PRIM_STEP_FINISHED);
syncGUI(SIG_NEXT_LINE);
#endif
/* Q <-- V */
for (i = 0; i < this->adj.size(); i++) {
if (!this->adj[i][0])
continue;
if (fib_heap->FibInsertNode(this->adj[i][0]) < 0) {
char buf[100];
sprintf(buf, "failed to insert node %d into fibonacci heap",
adj[i][0]->id);
throw PrimException(fmtError(buf));
goto cleanup;
}
}
#ifdef WITH_GUI // finished FibHeap construction
NEXT_LINE(++line);
tmp_line[0] = line;
syncGUI(SIG_NEXT_LINE);
#endif
/* find minimum spanning tree (set of edges) */
while (!fib_heap->FibIsEmpty()) {
#ifdef WITH_GUI
line = tmp_line[0];
NEXT_LINE(line);
syncGUI(SIG_NEXT_LINE);
#endif
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
/* u <- Extract-Min(Q) */
u = fib_heap->FibExtractMin();
if (!u) {
throw PrimException(fmtError("failed to extract minimal"
" value node"));
goto cleanup;
}
#ifdef WITH_GUI // finished Extract-Min(Q)
NEXT_LINE(++line);
syncGUI(SIG_MIN_EXTRACTED, u->id);
syncGUI(SIG_NEXT_LINE);
#endif
/* if pi[u] then A = A U (u, pi[u]) */
if (pi[u->id]) {
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
this->min_spanning_tree.push_back(make_tuple(u->id,
pi[u->id]->id));
this->mst_cost += weight(u->id,pi[u->id]->id);
#ifdef WITH_GUI // finished A U (u, pi[u])
syncGUI(SIG_MST_UPDATED, u->id, pi[u->id]->id);
#endif
}
#ifdef WITH_GUI
else
NEXT_LINE(++line);
#endif
#ifdef WITH_GUI
NEXT_LINE(++line);
tmp_line[1] = line;
syncGUI(SIG_NEXT_LINE);
#endif
/* for each v in Adj[u] */
for (i = 1; i < this->adj[u->id].size(); i++) {
#ifdef WITH_GUI
line = tmp_line[1];
NEXT_LINE(line);
syncGUI(SIG_NEXT_LINE);
#endif
v = this->adj[u->id][i];
unsigned uid = u->id;
unsigned vid = v->id;
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
/* if v in Q and w(u,v) < key[v] */
if ((v = fib_heap->FibFindNode(vid)) &&
(w = weight(uid, vid)) < v->key) {
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
/* pi[v] <-- u */
pi[vid] = u;
#ifdef WITH_GUI
NEXT_LINE(++line);
syncGUI(SIG_NEXT_LINE);
#endif
/* key[v] <-- w(u,v) */
fib_heap->FibDecreaseKey(v, w);
#ifdef WITH_GUI // finished Decrease key
syncGUI(SIG_PRIM_STEP_FINISHED);
#endif
}
}
}
ret = 0;
cleanup:
this->status_finished = true;
#ifdef WITH_GUI
sigEvent(SIG_FINISHED_ALL);
#endif
return ret;
}
Prim::Prim()
{
try {
this->fib_heap = new FibHeap;
}
catch (bad_alloc&) {
throw PrimException(fmtError("failed to create Fibonacci heap"));
}
}
Prim::~Prim()
{
for (unsigned i = 0; i < this->adj.size(); i++) {
FibNodePtr node = this->adj[i][0];
delete node;
}
delete this->fib_heap;
}
FibNodePtr
Prim::PrimAddVertex(unsigned id)
{
FibNodePtr node = nullptr;
if (id == UINT_MAX)
node = fib_heap->FibCreateNode();
else
node = fib_heap->FibCreateNode(id);
if (node) {
/* if for some reason user randomly chooses ID, we fill the nodeset
* with blanks
*/
if (id > this->next_id) {
unsigned id_difference = id - this->next_id;
for (unsigned i = 0; i < id_difference; i++, this->next_id++) {
this->adj.push_back(AdjNodeEdges());
this->adj[this->next_id].push_back(nullptr);
}
} else if (id < this->next_id) {
this->adj[id][0] = node;
return node;
}
this->adj.push_back(AdjNodeEdges());
this->adj[node->id].push_back(node);
this->next_id = id + 1;
}
return node;
}
int
Prim::PrimAddEdge(unsigned u, unsigned v)
{
/* check for unexpected edge */
if (u >= this->next_id || v >= this->next_id) {
char buf[100];
sprintf(buf, "failed to insert edge (%d,%d): invalid edge", u,v);
throw PrimException(fmtError(buf));
return -1;
}
/* check for conflicting edges */
for (vector<tuple<unsigned, unsigned>>::iterator it = this->edges.begin();
it != this->edges.end();
++it) {
unsigned my_u, my_v;
tie(my_u, my_v) = *it; /* untie edge to separate nodes */
if ((my_u == u && my_v == v) || (my_u == v && my_v == u)) {
char buf [100];
sprintf(buf,
"failed to insert edge (%d,%d): edge already exists",
u,v);
throw PrimException(fmtError(buf));
return -1;
}
}
/* insert edge into list of all edges, so we can later check
* if user tries to insert reverted edge as well which must fail
* with error, as Prim's algorithm works only for undirected graphs
*/
this->edges.push_back(make_tuple(u,v));
/* add v into u's adjacency list */
this->adj[u].push_back(adj[v][0]);
/* add u into v's adjacency list */
this->adj[v].push_back(adj[u][0]);
return 0;
}
#ifdef WITH_GUI
FibNodePtr
Prim::PrimGetHeapMin(void)
{
if (this->fib_heap)
return this->fib_heap->FibGetMin();
return nullptr;
}
#endif