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lammps/lib/poems/SystemProcessor.h
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SystemProcessor.h
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/*
*_________________________________________________________________________*
* POEMS: PARALLELIZABLE OPEN SOURCE EFFICIENT MULTIBODY SOFTWARE *
* DESCRIPTION: SEE READ-ME *
* FILE NAME: SystemProcessor.h *
* AUTHORS: See Author List *
* GRANTS: See Grants List *
* COPYRIGHT: (C) 2005 by Authors as listed in Author's List *
* LICENSE: Please see License Agreement *
* DOWNLOAD: Free at www.rpi.edu/~anderk5 *
* ADMINISTRATOR: Prof. Kurt Anderson *
* Computational Dynamics Lab *
* Rensselaer Polytechnic Institute *
* 110 8th St. Troy NY 12180 *
* CONTACT: anderk5@rpi.edu *
*_________________________________________________________________________*/
#ifndef _SYS_PROCESSOR_H_
#define _SYS_PROCESSOR_H_
#include "poemslist.h"
#include "poemstree.h"
#include "POEMSChain.h"
struct POEMSNode {
List<POEMSNode> links;
List<bool> taken;
int idNumber;
bool visited;
~POEMSNode(){
for(int i = 0; i < taken.GetNumElements(); i++)
{
delete taken(i);
}
};
};
class SystemProcessor{
private:
Tree nodes;
// List<POEMSNode> forDeletion;
List<POEMSChain> headsOfSystems;
List<List<int> > ringsInSystem;
POEMSNode * findSingleLink(TreeNode * aNode);
POEMSChain * AddNewChain(POEMSNode * currentNode);
bool setLinkVisited(POEMSNode * firstNode, POEMSNode * secondNode);
public:
SystemProcessor(void);
~SystemProcessor(void) {
headsOfSystems.DeleteValues();
for(int i = 0; i < ringsInSystem.GetNumElements(); i++)
{
for(int k = 0; k < ringsInSystem(i)->GetNumElements(); i++)
{
delete (*ringsInSystem(i))(k);
}
}
};
void processArray(int** links, int numLinks);
List<POEMSChain> * getSystemData();
int getNumberOfHeadChains();
};
SystemProcessor::SystemProcessor(void){
}
void SystemProcessor::processArray(int** links, int numLinks)
{
bool * false_var; //holds the value false; needed because a constant cannot be put into a list; the list requires a
//reference.
for(int i = 0; i < numLinks; i++) //go through all the links in the input array
{
if(!nodes.Find(links[i][0])) //if the first node in the pair is not found in the storage tree
{
POEMSNode * newNode = new POEMSNode; //make a new node
// forDeletion.Append(newNode);
newNode->idNumber = links[i][0]; //set its ID to the value
newNode->visited = false; //set it to be unvisited
nodes.Insert(links[i][0], links[i][0], (void *) newNode); //and add it to the tree storage structure
}
if(!nodes.Find(links[i][1])) //repeat process for the other half of each link
{
POEMSNode * newNode = new POEMSNode;
// forDeletion.Append(newNode);
newNode->idNumber = links[i][1];
newNode->visited = false;
nodes.Insert(links[i][1], links[i][1], (void *) newNode);
}
POEMSNode * firstNode = (POEMSNode *)nodes.Find(links[i][0]); //now that we are sure both nodes exist,
POEMSNode * secondNode = (POEMSNode *)nodes.Find(links[i][1]); //we can get both of them out of the tree
firstNode->links.Append(secondNode); //and add the link from the first to the second...
false_var = new bool;
*false_var = false; //make a new false boolean to note that the link between these two
firstNode->taken.Append(false_var); //has not already been taken, and append it to the taken list
secondNode->links.Append(firstNode); //repeat process for link from second node to first
false_var = new bool;
*false_var = false;
secondNode->taken.Append(false_var);
}
TreeNode * temp = nodes.GetRoot(); //get the root node of the node storage tree
POEMSNode * currentNode;
do
{
currentNode = findSingleLink(temp); //find the start of the next available chain
if(currentNode != NULL)
{
headsOfSystems.Append(AddNewChain(currentNode)); //and add it to the headsOfSystems list of chains
}
}
while(currentNode != NULL); //repeat this until all chains have been added
}
POEMSChain * SystemProcessor::AddNewChain(POEMSNode * currentNode){
if(currentNode == NULL) //Termination condition; if the currentNode is null, then return null
{
return NULL;
}
int * tmp;
POEMSNode * nextNode = NULL; //nextNode stores the proposed next node to add to the chain. this will be checked to make sure no backtracking is occuring before being assigned as the current node.
POEMSChain * newChain = new POEMSChain; //make a new POEMSChain object. This will be the object returned
if(currentNode->links.GetNumElements() == 0) //if we have no links from this node, then the whole chain is only one node. Add this node to the chain and return it; mark node as visited for future reference
{
currentNode->visited = true;
tmp = new int;
*tmp = currentNode->idNumber;
newChain->listOfNodes.Append(tmp);
return newChain;
}
while(currentNode->links.GetNumElements() <= 2) //we go until we get to a node that branches, or both branches have already been taken both branches can already be taken if a loop with no spurs is found in the input data
{
currentNode->visited = true;
tmp = new int;
*tmp = currentNode->idNumber;
newChain->listOfNodes.Append(tmp); //append the current node to the chain & mark as visited
//cout << "Appending node " << currentNode->idNumber << " to chain" << endl;
nextNode = currentNode->links.GetHeadElement()->value; //the next node is the first or second value stored in the links array
//of the current node. We get the first value...
if(!setLinkVisited(currentNode, nextNode)) //...and see if it points back to where we came from. If it does...
{ //either way, we set this link as visited
if(currentNode->links.GetNumElements() == 1) //if it does, then if that is the only link to this node, we're done with the chain, so append the chain to the list and return the newly created chain
{
// headsOfSystems.Append(newChain);
return newChain;
}
nextNode = currentNode->links.GetHeadElement()->next->value;//follow the other link if there is one, so we go down the chain
if(!setLinkVisited(currentNode, nextNode)) //mark link as followed, so we know not to backtrack
{
// headsOfSystems.Append(newChain);
return newChain; //This condition, where no branches have occurred but both links have already
//been taken can only occur in a loop with no spurs; add this loop to the
//system (currently added as a chain for consistency), and return.
}
}
currentNode = nextNode; //set the current node to be the next node in the chain
}
currentNode->visited = true;
tmp = new int;
*tmp = currentNode->idNumber;
newChain->listOfNodes.Append(tmp); //append the last node before branch (node shared jointly with branch chains)
//re-mark as visited, just to make sure
ListElement<POEMSNode> * tempNode = currentNode->links.GetHeadElement(); //go through all of the links, one at a time that branch
POEMSChain * tempChain = NULL; //temporary variable to hold data
while(tempNode != NULL) //when we have followed all links, stop
{
if(setLinkVisited(tempNode->value, currentNode)) //dont backtrack, or create closed loops
{
tempChain = AddNewChain(tempNode->value); //Add a new chain created out of the next node down that link
tempChain->parentChain = newChain; //set the parent to be this chain
newChain->childChains.Append(tempChain); //append the chain to this chain's list of child chains
}
tempNode = tempNode->next; //go to process the next chain
}
//headsOfSystems.Append(newChain); //append this chain to the system list
return newChain;
}
POEMSNode * SystemProcessor::findSingleLink(TreeNode * aNode)
//This function takes the root of a search tree containing POEMSNodes and returns a POEMSNode corresponding to the start of a chain in the
//system. It finds a node that has not been visited before, and only has one link; this node will be used as the head of the chain.
{
if(aNode == NULL)
{
return NULL;
}
POEMSNode * returnVal = (POEMSNode *)aNode->GetAuxData(); //get the poemsnode data out of the treenode
POEMSNode * detectLoneLoops = NULL; //is used to handle a loop that has no protruding chains
if(returnVal->visited == false)
{
detectLoneLoops = returnVal; //if we find any node that has not been visited yet, save it
}
if(returnVal->links.GetNumElements() == 1 && returnVal->visited == false) //see if it has one element and hasnt been visited already
{
return returnVal; //return the node is it meets this criteria
}
returnVal = findSingleLink(aNode->Left()); //otherwise, check the left subtree
if(returnVal == NULL) //and if we find nothing...
{
returnVal = findSingleLink(aNode->Right()); //check the right subtree
}
if(returnVal == NULL) //if we could not find any chains
{
returnVal = detectLoneLoops; //see if we found any nodes at all that havent been processed
}
return returnVal; //return what we find (will be NULL if no new chains are
//found)
}
bool SystemProcessor::setLinkVisited(POEMSNode * firstNode, POEMSNode * secondNode)
//setLinkVisited sets the links between these two nodes as visited. If they are already visited, it returns false. Otherwise, it sets
//them as visited and returns true. This function is used to see whether a certain path has been taken already in the graph structure.
//If it has been, then we need to know so we dont follow it again; this prevents infinite recursion when there is a loop, and prevents
//backtracking up a chain that has already been made. The list of booleans denoting if a link has been visited is called 'taken' and is
//part of the POEMSNode struct. The list is the same size as the list of pointers to other nodes, and stores the boolean visited/unvisited
//value for that particular link. Because each link is represented twice, (once at each node in the link), both of the boolean values need
//to be set in the event that the link has to be set as visited.
{
//cout << "Checking link between nodes " << firstNode->idNumber << " and " << secondNode->idNumber << "... ";
ListElement<POEMSNode> * tmp = firstNode->links.GetHeadElement(); //get the head element of the list of pointers for node 1
ListElement<bool> * tmp2 = firstNode->taken.GetHeadElement(); //get the head element of the list of bool isVisited flags for node 1
while(tmp->value != NULL || tmp2->value != NULL) //go through untill we reach the end of the lists
{
if(tmp->value == secondNode) //if we find the link to the other node
{
if(*(tmp2->value) == true) //if the link has already been visited
{
//cout << "visited already" << endl;
return false; //return false to indicate that the link has been visited before this attempt
}
else //otherwise, visit it
{
*tmp2->value = true;
}
break;
}
tmp = tmp->next; //go check next link
tmp2 = tmp2->next;
}
tmp = secondNode->links.GetHeadElement(); //now, if the link was unvisited, we need to go set the other node's list such that
//it also knows this link is being visited
tmp2 = secondNode->taken.GetHeadElement();
while(tmp->value != NULL || tmp2->value != NULL) //go through the list
{
if(tmp->value == firstNode) //if we find the link
{
if(*(tmp2->value) == true) //and it has already been visited, then signal an error; this shouldnt ever happen
{
cout << "Error in parsing structure! Should never reach this condition! \n" <<
"Record of visited links out of synch between two adjacent nodes.\n";
return false;
}
else
{
*tmp2->value = true; //set the appropriate value to true to indicate this link has been visited
}
break;
}
tmp = tmp->next;
tmp2 = tmp2->next;
}
//cout << "not visited" << endl;
return true; //return true to indicate that this is the first time the link has been visited
}
List<POEMSChain> * SystemProcessor::getSystemData(void) //Gets the list of POEMSChains that comprise the system. Might eventually only
//return chains linked to the reference plane, but currently returns every chain
//in the system.
{
return &headsOfSystems;
}
int SystemProcessor::getNumberOfHeadChains(void) //This function isnt implemented yet, and might be taken out entirely; this was a holdover
//from when I intended to return an array of chain pointers, rather than a list of chains
//It will probably be deleted once I finish figuring out exactly what needs to be returned
{
return 0;
}
#endif
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