parfor energyplus co-simulation toolbox

I am using the co-simulation toolbox to simulate multiple buildings in energyplus.(Jiri Dostal (2019). EnergyPlus Co-simulation Toolbox (https://www.github.com/dostaji4/EnergyPlus-co-simulation-toolbox), GitHub. Retrieved February 5, 2019.) I managed to use a forloop. To reduce the computation time I would like to run this code in parallel using parfor. However I cannot make it work. Do you have any tips or suggestions? Thanks in advance!

What I tried until now:

I changed for in parfor (see code below). this gives the following error:

Error using mlep/acceptSocket (line 1129)

Java exception occurred:

java.net.SocketTimeoutException: Accept timed out

at java.net.DualStackPlainSocketImpl.waitForNewConnection(Native Method)

at java.net.DualStackPlainSocketImpl.socketAccept(Unknown Source)

at java.net.AbstractPlainSocketImpl.accept(Unknown Source)

at java.net.PlainSocketImpl.accept(Unknown Source)

at java.net.ServerSocket.implAccept(Unknown Source)

at java.net.ServerSocket.accept(Unknown Source)

Error in mlep/start (line 283)

obj.acceptSocket;

Error in cosimeplus (line 3)

parfor c=1:20

adding (c) to all "ep." files. This gives the following error:

Error using cosimeplus (line 3)

Error: The variable ep in a parfor cannot be classified.

See Parallel for Loops in MATLAB, "Overview".

adding Tabel(c)=logTable This gives the following error:

Error using cosimeplus (line 3)

Error: The temporary variable logTable in a parfor is uninitialized.

See Parallel for Loops in MATLAB, "Uninitialized Temporaries".

%% 2 Instantiate the co-simulation tool
ep=[];
parfor c=1:20
textFileName = ['matlabtest' num2str(c) 'a.idf'];
ep = mlep;
% Building simulation file
ep.idfFile(c) = textFileName;'rt';
% Weather file
ep.epwFile = 'Amsterdam';
% Initialize
ep.initialize; 
inputs = ep.inputTable;
outputs = ep.outputTable;
timestep = ep.timestep; %[s]
% Simulation length
endTime = 365*24*60*60; %[s]
% Logging
logTable = table('Size',[0, 1 + ep.nOut],...
    'VariableTypes',repmat({'double'},1,1 + ep.nOut),...
    'VariableNames',[{'Time'}; ep.outputSigName]);
% Start co-simulation
ep.start;
t = 0;
iLog = 1;
while t < endTime
    
    % Specify inputs
    u = [18 30]; % [heating setpoint, cooling setpoint]
    
    % Send inputs & get outputs from EnergyPlus
    y = ep.step(u); 
    
    % Obtain elapsed simulation time 
    t = ep.time; %[s]
    
    % Or alternatively by using 'read' and 'write' methods. Please note that the 'read'
    % method must preceed the 'write' method.
    %{
    % Get outputs from EnergyPlus
    [y, t] = ep.read;
    
    % Send inputs to EnergyPlus
    ep.write(u,t); 
    %}
    
    % Log data
    logTable(iLog, :) = num2cell([t y']);
    iLog = iLog + 1;  
    
end

% Stop co-simulation
ep.stop;

%%pe-allocate arrays
% 3 calculate RMSE
Eplus_heating(c)=((sum(logTable.EP_BOILER__Boiler_Gas_Rate(2:8761))))/1000
Eplus_DHW(c)=((sum(logTable.EP_DHW_LOOP_WATER_HEATER__Water_Heater_Gas_Rate(2:8761))))/1000
Eplus_tot(c)=Eplus_heating(c)+Eplus_DHW(c)

end

Answer 1

[Edric Ellis]

I think the problem here is that the toolbox is not designed to be run multiple times simultaneously on a single machine. I took a brief scan through the toolbox code, and it looks like the main problem is that I think each worker is attempting to write out the same "socket.cfg" file to indicate to the external process how to communicate. It might work to try and set each mlep instance to have a unique workDir, something like this perhaps (untested!):

parfor c = 1:20
    t = getCurrentTask();
    d = fullfile(tempdir, sprintf('worker_%d', t.ID));
    if ~exist(d, 'dir'), mkdir(d); end
    ep = mlep;
    ep.workDir = d;
    ...
end

[Paula van den Brom]

Dear Edric,

Thank you very much for your help. The code is working.

However if I have more simulations than the number of parallel workers I get an error.

Do you have any idea why this is happening?

Thank you very much in advance

This is the error I get (when using 2 workers and trying to simulate 8 cases in parallel):

Warning: Found process "energyplus", ID = 6936, started 0 minutes ago. Terminating the process.

> In mlep/killProcessByName (line 1020)Error using mlep/acceptSocket (line 1129)

Java exception occurred:

java.net.SocketTimeoutException: Accept timed out

at java.net.DualStackPlainSocketImpl.waitForNewConnection(Native Method)

at java.net.DualStackPlainSocketImpl.socketAccept(Unknown Source)

at java.net.AbstractPlainSocketImpl.accept(Unknown Source)

at java.net.PlainSocketImpl.accept(Unknown Source)

at java.net.ServerSocket.implAccept(Unknown Source)

at java.net.ServerSocket.accept(Unknown Source)

Error in mlep/start (line 283)

obj.acceptSocket;

Error in RMSE_sim_7SJ_PvdB (line 242)

parfor c=1:8

[Edric Ellis]

Perhaps you need to ensure the mlep object is correctly cleaned at the end of each loop iteration? Maybe

parfor ...
    ...
    ep = mlep;
    ... % Use 'ep'
    delete(ep); % Force clean-up of 'ep'
end

This will force the mlep/delete method to run earlier than it might otherwise, and should clean up the socket (I think).

[Cong Tran]

Hello,

when I try to create the .idf file (ExternalInterface:Actuator), and simulate on matlab, but I got the error like that:

Error using mlep/loadIdf (line 772)

Subscripting a table using linear indexing (one subscript) or multidimensional indexing

(three or more subscripts) is not supported. Use a row subscript and a variable subscript.

Could you please help me solve this error?

[Jiri Dostal]

Cong Tran - this was a bug and it should be fixed in latest uploads.