Thread: Improving MATLAB for loops!

I am very, very new to Matlab. I migrated c++ code to Matlab, because I knew vectors were involved in the problem, and thought I could get a performance boost using the language. I pretty much just translated the code line-by-line. My inexperience was obvious, since the code runs slower than it did in c++....
Obviously, I'm not taking full advantage of the language's features... or maybe the problem just isn't suited for it.
Below are the two code segments (both loops) that have become a huge bottle neck. It is a graph problem, with this iteration having 501 points (24675 edges). The program also used for much bigger test sets, up to 20,000 points, so speed is a necessity.
The first code segment takes about a minute. It reads in all the point values in a text file. master_graph is a map (int keys) of vectors (edges)

Code:

for i=1:(numEdges)    
    %? change types to save space?    
    line = fgets(fid); 
    %# read line by line    
    A = sscanf(line,'%i %i %i');   
    num1 = A(1);    
    num2 = A(2);    
    num3 = A(3);
    temp_node = num1;    
    temp_edge.endpoint=num2;    
    temp_edge.distance=num3;
    if (temp_edge.distance > max_distance_for_wb) 
           max_distance_for_wb = temp_edge.distance;   
    end
    if(isKey(master_graph,temp_node))
                master_graph(temp_node) = [master_graph(temp_node) temp_edge];
    else
        master_graph(temp_node) = temp_edge;    
    end
    swap = temp_node;
    temp_node = temp_edge.endpoint;
    temp_edge.endpoint = swap;
    if(isKey(master_graph,temp_node)) 
         master_graph(temp_node) = [master_graph(temp_node) temp_edge];     
    else 
        master_graph(temp_node) = temp_edge;    
    end
end

The fact that reading from a file is involved, it will obviously be slower, but is there a better way of doing this?
The second code segment involves two nested for-loops. wsp and graph are in the same format as master_graph. It loops through each key and then each of the edges (stored in a vector mapped with that key). I know loops can be optimized with 'vectorization', but I'm kinda clueless. Any suggestions?

Code:

        % for each node in wsp        
        %############################################
        for it = 1:wsp.Count()
             %? for each edge in the graph
             key = thekeys{it};
             for i = 1:length(graph(key))
                 thisEdge = graph(key);
                 thisPoint = thisEdge(i);
                 if (thisPoint.distance > max_edge_in_prim)
                      continue;
                end
                if(terminal(thisPoint.endpoint))
                     str = sprintf('\tT');
                     fprintf(str);
                     cost_of_addition = costFunc(thisPoint.distance, path_length(key));
                else
                     %disp('Not Terminal!');
                     str = sprintf('\t ');
                     fprintf(str);
                     cost_of_addition = (TRENCH_COST * thisPoint.distance);
                end
                % BENEFIT
                % calculate cost one time...
                curr_cost = costFunc(thisPoint.distance, path_length(key));
                % added (TRENCH_COST *) below
                curr_cost = (WC * curr_cost) - (WB * benefit(thisPoint.endpoint));
                str = sprintf('( %d , %d) C=%d B=%d T=%d',key,thisPoint.endpoint,costFunc(thisPoint.distance,path_length(key)), benefit(thisPoint.endpoint),curr_cost);                fprintf(str);
                disp(' ');
                % curr_cost holds the overall value of which the min should
                % be tracked
                if (first || curr_cost < min)
                     first = 0;
                     min = curr_cost;
                     select = thisPoint.endpoint; 
                     node = key;
                     distance = thisPoint.distance;
                     node_added = 1; 
                     cost_of_min = cost_of_addition;
                end
            end
     end

Any suggestions would be HUGELY appreciated. I need to speed this thing up anyway possible. The code runs in C++ in under a second. This code takes MINUTES. Hopefully I can avoid embarrassment in my suggestion of translating to matlab. Also, I only have access to R2010b.
Thanks Greg

C++ is faster than MATLAB. MATLAB is applied to solve a problem easier, but the runtime is not faster. So if you did the algorithm in C++ then you need no to turn to MATLAB. However you can run your C++ application within MATLAB.

Yes i use C++.It is faster than MALTAB.
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