Parallel computing and number of cores in Matlab - matlab

Question

I am trying to run some code that creates a sketch from an image:
https://github.com/panly099/sketchSynthesis
After getting it going on windows, im running into what I think are performance issues. The program is supposed to complete the task in 5 minutes, but my computer wont complete the task at all (ive waited at least 30 minutes)
My computer has only 4GB of RAM and is an Intel I3.
The code uses parallel computing apparently, so to active Parfor I did:
if matlabpool('size') == 0
matlabpool open 2
end
Which gave me "connected to 2 workers"
The CPU usage looks like: https://imgur.com/a/lkMRg
Im wondering if someone could explain it to me simply how I might be able to speed it up to complete the image in under 5 minutes, or tell me if I need to upgrade my RAM or amount of cores.
The guy who wrote the code said he ran it originally on an 8-core server.
The code that includes the parfor loop comes from
https://github.com/panly099/sketchSynthesis/blob/master/functions/sketchDetect.m :
function [ detection ] = sketchDetect(sample, strokeModel, configurations, searchRatio, threshold, appGeoWeight)
% This function anchors the stroke model on the given input sketch or edge
% map sample via a dynamic programming process.
% Input :
% sample : the input sketch or edge map sample.
% strokeModel : the stroke model.
% configurations : the sampled configurations of the object.
% searchRatio : the search ratio of the original stroke bounding box.
% threshold : the chamfer matching threshold.
% appGeoWeight : the balance between the appearance and the geometry.
% Output :
% detection : the detected model instance.
% Author :
% panly099#gmail.com
% Version :
% 1.1 07/06/2016
if nargin < 5
threshold = 0.5;
end
if nargin < 6
appGeoWeight = 0.5;
end
baseScale = 1;
baseAspect = 1;
overlapWeight = 0.001;
mst = strokeModel.mst;
avgWidth = strokeModel.avgWidth;
avgHeight = strokeModel.avgHeight;
clusterBbox = strokeModel.clusterBbox;
[height, width] = size(sample);
numConf = length(configurations);
detections = cell(1, numConf);
energy = zeros(1,numConf);
for a = 1 : numConf
configuration = configurations{a};
%% sampling by fast directional chamfer matching (fdcm)
numCluster = length(configuration);
strokeCandidates = cell(1, numCluster);
parfor j = 1 : numCluster
fprintf('current stroke id: %d\n', j);
strokeImg = configuration{j};
strBbox = getBoundingBox(strokeImg,0);
strokeImg = strokeImg(strBbox(2):strBbox(4), strBbox(1):strBbox(3));
% compute the search region
curBbox = clusterBbox(:,j)';
% curBbox = strBbox;
curWidth = curBbox(3) - curBbox(1);
curHeight = curBbox(4) - curBbox(2);
searchRegion = [curBbox(1) - ceil((searchRatio - 1) / 2 * curWidth), curBbox(2) - ceil((searchRatio - 1) / 2 * curHeight), ...
curBbox(3) + ceil((searchRatio - 1) / 2 * curWidth), curBbox(4) + ceil((searchRatio - 1) / 2 * curHeight)];
if searchRegion(1) < 1
searchRegion(1) = 1;
end
if searchRegion(2) < 1
searchRegion(2) = 1;
end
if searchRegion(3) > width
searchRegion(3) = width;
end
if searchRegion(4) > height
searchRegion(4) = height;
end
img = sample(searchRegion(2):searchRegion(4), searchRegion(1):searchRegion(3));
% fdcm anchoring
[strokeMatched, cost] = chamferLocate(img, strokeImg, baseScale, baseAspect, threshold);
% figure;imshow(~strokeImg);figure;imshow(~img);
if size(strokeMatched,1) > 1000
stop = 1;
end
for s = 1 : length(strokeMatched)
tmpSample = zeros(height, width);
tmpSample(searchRegion(2):searchRegion(4), searchRegion(1):searchRegion(3)) = strokeMatched{s};
if cost(s) <= 0
cost(s) = 1;
end
strokeCandidates{j}(s,:) = [{tmpSample}, cost(s)];
% figure;imshow(~strokeMatched{s});
end
% figure;imshow(sample);
end
%% energy minimization by dynamic programming
% backward
fprintf('Backward propogation\n');
for i = length(mst) : -1 : 2
fprintf('Scanning MST layer: %d\n', i);
curLayer = mst{i};
for j = 1 : length(curLayer)
% parents = [];
curEdge = curLayer{j};
curParent = curEdge{1}(2);
% parents = [parents curParent];
curChild = curEdge{1}(1);
curParam = curEdge{2};
curParentChildIdx = size(strokeCandidates{curParent},2) + 1;
curParentCandidates = strokeCandidates{curParent}(:,1);
curChildCandidates = strokeCandidates{curChild};
for p = 1 : length(curParentCandidates)
tmpBbox = getBoundingBox(curParentCandidates{p}, 0);
curParentCenter = ceil([(tmpBbox(2)+tmpBbox(4))/2, (tmpBbox(1)+tmpBbox(3))/2]);
childCosts = ones(1, size(curChildCandidates, 1))*Inf;
for c = 1 : size(curChildCandidates, 1)
tmpBbox = getBoundingBox(curChildCandidates{c,1},0);
curChildCenter = ceil([(tmpBbox(2)+tmpBbox(4))/2, (tmpBbox(1)+tmpBbox(3))/2]);
geoNorm = 1/40;
curCost = appGeoWeight * curChildCandidates{c,2} - (1-appGeoWeight) * geoNorm * log(mvnpdf(curChildCenter-curParentCenter, ...
curParam{2},curParam{3}));
for gc = 3 : size(curChildCandidates,2)
curCost = curCost + curChildCandidates{c,gc}(2);
end
childCosts(c) = curCost;
end
[minCost, minIdx] = min(childCosts);
if minCost == Inf
stop = 1;
end
strokeCandidates{curParent}{p, curParentChildIdx} = [curChild, minCost, minIdx];
end
% % adding overlapping penalty
% parents = unique(parents);
% for u = 1 : length(parents)
% curParent = parents(u);
% for p = 1 : size(strokeCandidates{curParent}, 1)
% curParentImg = strokeCandidates{curParent}{p,1};
% overlapCost = 0;
% for c = 3 : size(strokeCandidates{curParent}, 2)
% curChild = strokeCandidates{curParent}{p,c}(1);
% curChildIdx = strokeCandidates{curParent}{p,c}(3);
% curChildImg = strokeCandidates{curChild}{curChildIdx,1};
% curOverlap = curParentImg.*curChildImg;
% overlapCost = overlapCost + sum(curOverlap(:)) * overlapWeight;
% end
% strokeCandidates{curParent}{p,2} = strokeCandidates{curParent}{p,2} + overlapCost;
% end
% end
end
end
% forward
fprintf('forward propogation\n');
fprintf('Scanning MST layer: %d\n', 1);
detection = cell(1, numCluster);
root = mst{1};
rootCosts = [];
for i = 1 : size(strokeCandidates{root},1)
cost = strokeCandidates{root}{i,2};
for j = 3 : size(strokeCandidates{root},2)
cost = cost + strokeCandidates{root}{i,j}(2);
end
rootCosts(end+1) = cost;
end
[~,rootSelected] = min(rootCosts);
minCost = rootCosts(rootSelected);
detection{root} = strokeCandidates{root}{rootSelected, 1};
for i = 2 : length(mst)
fprintf('Scanning MST layer: %d\n', i);
curLayer = mst{i};
for j = 1 : length(curLayer)
curEdge = curLayer{j};
curParent = curEdge{1}(2);
curChild = curEdge{1}(1);
curParam = curEdge{2};
curParentCandidate = detection{curParent};
curChildCandidates = strokeCandidates{curChild};
tmpBbox = getBoundingBox(curParentCandidate, 0);
curParentCenter = ceil([(tmpBbox(2)+tmpBbox(4))/2, (tmpBbox(1)+tmpBbox(3))/2]);
childCosts = ones(1, size(curChildCandidates, 1))*Inf;
for c = 1 : size(curChildCandidates, 1)
tmpBbox = getBoundingBox(curChildCandidates{c,1},0);
curChildCenter = ceil([(tmpBbox(2)+tmpBbox(4))/2, (tmpBbox(1)+tmpBbox(3))/2]);
geoNorm = 1/40;
curCost = appGeoWeight * curChildCandidates{c,2} - (1-appGeoWeight) * geoNorm * log(mvnpdf(curChildCenter-curParentCenter, ...
curParam{2},curParam{3}));
for gc = 3 : size(curChildCandidates,2)
curCost = curCost + curChildCandidates{c,gc}(2);
end
childCosts(c) = curCost;
end
[~, minId] = min(childCosts);
detection{curChild} = curChildCandidates{minId,1};
end
end
detections{a} = detection;
energy(a) = minCost;
end
[~,minIdx] = min(energy);
detection = detections{minIdx};
% visualize the detection
% synthesized = zeros(height, width);
% for i = 1 : length(detection)
% if sum(detection{i}(:))>1
% synthesized = synthesized + detection{i};
% end
% end
% figure;imshow(~sample);
% figure;imshow(~synthesized);
end