computer_cost.m

function  [OPEN,CLOSED]=computer_cost(xNode,yNode,xTarget,yTarget,MAX_X,MAX_Y,OPEN,CLOSED);

CLOSED_COUNT=size(CLOSED,1);
%set the starting node as the first node

OPEN_COUNT=1;
path_cost=0;

goal_distance=distance(xNode,yNode,xTarget,yTarget);
OPEN(OPEN_COUNT,:)=insert_open(xNode,yNode,xNode,yNode,path_cost,goal_distance,goal_distance);
OPEN(OPEN_COUNT,1)=0;
CLOSED_COUNT=CLOSED_COUNT+1;
CLOSED(CLOSED_COUNT,1)=xNode;
CLOSED(CLOSED_COUNT,2)=yNode;
NoPath=1;
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% START ALGORITHM
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
while((xNode ~= xTarget || yNode ~= yTarget) && NoPath == 1)
%  plot(xNode+.5,yNode+.5,'go');
 exp_array=expand_array(xNode,yNode,path_cost,xTarget,yTarget,CLOSED,MAX_X,MAX_Y);
 exp_count=size(exp_array,1);
 %UPDATE LIST OPEN WITH THE SUCCESSOR NODES
 %OPEN LIST FORMAT
 %--------------------------------------------------------------------------
 %IS ON LIST 1/0 |X val |Y val |Parent X val |Parent Y val |h(n) |g(n)|f(n)|
 %--------------------------------------------------------------------------
 %EXPANDED ARRAY FORMAT
 %--------------------------------
 %|X val |Y val ||h(n) |g(n)|f(n)|
 %--------------------------------
 for i=1:exp_count
    flag=0;
    for j=1:OPEN_COUNT
        if(exp_array(i,1) == OPEN(j,2) && exp_array(i,2) == OPEN(j,3) )
            OPEN(j,8)=min(OPEN(j,8),exp_array(i,5)); %#ok<*SAGROW>
            if OPEN(j,8)== exp_array(i,5)
                %UPDATE PARENTS,gn,hn
                OPEN(j,4)=xNode;
                OPEN(j,5)=yNode;
                OPEN(j,6)=exp_array(i,3);
                OPEN(j,7)=exp_array(i,4);
            end;%End of minimum fn check
            flag=1;
        end;%End of node check
%         if flag == 1
%             break;
    end;%End of j for
    if flag == 0
        OPEN_COUNT = OPEN_COUNT+1;
        OPEN(OPEN_COUNT,:)=insert_open(exp_array(i,1),exp_array(i,2),xNode,yNode,exp_array(i,3),exp_array(i,4),exp_array(i,5));
     end;%End of insert new element into the OPEN list
 end;%End of i for
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %END OF WHILE LOOP
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %Find out the node with the smallest fn 
  index_min_node = min_fn(OPEN,OPEN_COUNT,xTarget,yTarget);
  if (index_min_node ~= -1)    
   %Set xNode and yNode to the node with minimum fn
   xNode=OPEN(index_min_node,2);
   yNode=OPEN(index_min_node,3);
   path_cost=OPEN(index_min_node,6);%Update the cost of reaching the parent node
  %Move the Node to list CLOSED
  CLOSED_COUNT=CLOSED_COUNT+1;
  CLOSED(CLOSED_COUNT,1)=xNode;
  CLOSED(CLOSED_COUNT,2)=yNode;
  OPEN(index_min_node,1)=0;
  else
      %No path exists to the Target!!
      NoPath=0;%Exits the loop!
  end;%End of index_min_node check
end;%End of While Loop

end