Comments and Ratings

Hi Markus,

first of all -- you've developed a great tool that helps me a lot with my simulations in the field of audio signal processing. Seeing my dual quad core at 100% (instead of 13%) load warms my heart :).

Well, I'm not sure whether I'm getting something wrong here, but I had some problems when the function that is executed by the multicoremaster() (and the slaves) has more than one return value. It seems that in this case all but the first return values get lost. I applied a little trick that I found out about some time ago to solve this problem:
Everytime that feval() is called (in startmulticoremaster() and startmulticoreslave() ) I added something like this:

N_returnValues = nargout(functionHandleCell{k});
clear('returnValue'); % this is dirty! The next call doesn't work
     % without clearing "returnValue" beforehand if
     % N_returnValues==1. If it's greater->no
     % problem (even without clearing
     % "returnValue")
[returnValue{1:N_returnValues}] = feval(functionHandleCell{k}, parameterCell{k}{:}); % ha!
resultCell{k} = returnValue;

Doing so, the resultsCell that is returned from startmulticoremaster() is always a cell -- even if the called function has only one return value...

I hope this is of any value to anybody and that I'm not causing trouble by posting this hack :). I'm always open to learn a better solution....

Cheers, and thanks again for Multicore!

    Karl

Thank you very much for this great tool! I started using your code a few of months ago, and I must say it saved me lots of hours of work.

I have little bit of problem running the master and slave processes over the network. I am not sure how to share the folder over a linux network!
Anybody can help?

Hello, when i am running the multicoredemo, only the master is working, but not the slave. What am i doing wrong?
multithreading unabled/ is set to one core.
I use a duo core processor with windows vista and Matlab 7.8.0 R2009a 64-bit.
Thank you very much.

thank u for sharing markus, but can u tell me why when I run the codes in my computer, the codes is always error. and one more question for u, would u like to help me to explain Differential evolution algorithm. i 'm a student that interest to Differential evolution algorithm and would like to use this algorithm for solve optimization inventory supply chain for my research.
thank b4

Great tool!

helo,
based on the above comments im overwhelmed in using the code posted buy markus.ive been working on genetic algorithms n optimization toolbox for my problem on alkylation.Differential Evolution can also be applied to this prob but im not sure of how to handle the code. So could u plz give insights on how to work on it. i ve been using matlab-GA only n am a new user so i request to plz help me in dis regard.Im highly interested in workin on dis.

Hi, I used assignmentoptimal.* in a multitracking application, exactly in the scenario you described. It works very well. Great job, thank you.

Fantastic program, and particularly suited to my work with genetic algorithms. There is one mnor error I've noticed though. In startmulticoreslave, if you activate debug mode you reach the following line (77):

fileNr = str2double(regexptokens(parameterFileName,...
'parameters_\d+_(\d+)\.mat'));

But there is no regexptokens function, at least there isn't in R2007a or R2007b or R2008a. My solution is to replace this with the following lines (although I'm sure someone could come up with something more robust and/or elegent).

fileNrCell = regexp(parameterFileName,'parameters_\d+_(\d+)\.mat', 'tokens');

fileNr = str2double(fileNrCell{1});

The program is excellent though, thanks again!

I've been using multicore for a while now and its absolutely excellent. I'm running on 5 dual xeon x5460 as well as a couple of quad core boxes.

I was wondering if anyone compared performance of this toolbox with the parfor parallel computing matlab toolbox. Are they comparable?

I believe I'm bottlenecked now due to the hard disk I/O, so I was looking at the in memory possibilities of this or potentially upgrading my hd's to solid state to reduce the overhead.

BTW, I also tried precreating all the mat files once instead of doing multiple loops to reduce the I/O. Unfortunately, that didn't help as much as I hoped.

Don't get me wrong though, this is much, much, much faster than single threading, but as always we need to keep pushing :).

Thanks for this great contribution, it's very useful.

Correction:
I've used in under a grid of computers running different OS: GNU/Linux, Mac and Windows (XP). When the shared folder is on a network computer (not mapped to a local drive, for example: \\servername\sharedfolder); Windows systems fail trying to delete the semaphores, causing the master process run forever.

The solution I found is to slightly modify compsep.m and concatpath.m as follows:

_______________________________________________________
function str = chompsep(str)
unix_sep = '/';
pc_sep = '\';

if isunix && str(1)==pc_sep
    str = strrep(str, pc_sep, unix_sep);
elseif ispc && str(1)==unix_sep
    str = strrep(str, unix_sep, pc_sep);
end

if ~isempty(str) && (str(end) == unix_sep || str(end) == pc_sep)
str(end) = '';
end

_______________________________________________________
function str = concatpath(varargin)
unix_sep = '/';
pc_sep = '\';

str = '';
for n=1:nargin
curStr = varargin{n};
str = fullfile(str, chompsep(curStr));
end

if isunix && str(1)==pc_sep
    str = strrep(str, pc_sep, unix_sep);
elseif ispc && str(1)==unix_sep
    str = strrep(str, unix_sep, pc_sep);
end

I got the same problem as Rohaly. When master ends the computation, and there is a slave still working, the master computes the remaining job again, yielding an extra iteration.
The solution is to set MAXMASTEREVALUATIONS, with all its drawbacks, since i understand that this isn't a bug rather than a problem not knowing if the slave got interrupted.

BTW, it works like a charm.

It seems there is the possibility for master and slave to simultaneously evaluate the same set of parameters. For example, if slave starts evaluating a slow process, master can catch up, and there is nothing to prevent it to start the very same computation since slave hasn't generated the result file yet. There is also a bug in setfilesemaphore.m. dirStruct(k).datenum in line 78 should be datenum(dirStruct(k).date).

Markus,

I think the point Andrew Koh was making is that for some reason the ")" is part of the URL in your abstract, but not in Andrew's URL, so your URL does not get to Storn's website, but Andrew's does.

Scott

Perfect! Keep the good work Up!

Its absolutely excellent. Am using it now on my quad core machine and am probably going to buy another quad core just to see my models run so quickly. :)

Brilliant library. Works like a charm

Thanks for the very very useful code. I wanted to apply this code for 4-D, 3 space dimension and 1 time dimension. I got the error 'error in bestmem ~= lastbestmem', when I checked, obviously these two vectors have different lengths, then I changed parGridVector = cell2mat(paramDefCell(:,3));
to
parGridVector = cell2mat(paramDefCell(:,4));
and code seems to be working fine. Am I doing right?

many thanks,

One of the best optimizers I've used. The speedy support from Markus was invaluable and greatly appreciated. An amazing package. Straightforward to implement, flexible and provides results!

Excellent!

Ldd Lasss, please let me know why you gave a bad rating for my package!