NAME

Sim::OPT.

SYNOPSIS

  use Sim::OPT;
  opt;

DESCRIPTION

Sim::OPT is an optimization and parametric exploration program favouring problem decomposition. It can be used with simulation programs receiving text files as input and emitting text files as output. Sim::OPT's optimization modules (Sim::OPT, Sim::OPT::Descent) pursue optimization through block search, allowing blocks (subspaces) to overlap, and allowing a free intermix of sequential searches (inexact Gauss-Seidel method) and parallell ones (inexact Jacobi method). The Sim::OPT::Takechange module can seek for the least explored search paths when exploring new search spaces sequentially (following rules presented in: http://dx.doi.org/10.1016/j.autcon.2016.08.014). Sim::OPT::Morph, the morphing module, can manipulate parameters of simulation models. Other modules under the Sim::OPT namespace are Sim::OPT::Parcoord3d, a module which can convert 2D parallel coordinates plots into Autolisp instructions for obtaining 3D plots as Autocad drawings; and Sim::OPT::Interlinear, which can build metamodels from sparse multidimensional data, and the module Sim::OPT::Modish, capable of altering the shading values calculated with the ESP-r buildjng performance simulation platform (http://www.esru.strath.ac.uk/Programs/ESP-r.htm). The Sim::OPT's morphing and reporting modules contain several additional functions specifically targeting the ESP-r building performance simulation platform.

To install Sim::OPT, the command <cpanm Sim::OPT> has to be issued as a superuser. Sim::OPT can then be loaded through the command <use Sim::OPT> in a Perl repl. But to ease the launch, the batch file "opt" (which can be found packed in the "optw.tar.gz" file in "examples" folder in this distribution) can be copied in a work directory and the command <opt> may be issued. That command will launch Sim::OPT with the settings specified in the configuration file. When launched, OPT will ask the path to that file, which has to contain a suitable description of the operations to be accomplished and point to an existing simulation model.

The "$mypath" variable in the configuration file must be set to the work directory where the base model reside.

Besides an OPT configuration file, separate configuration files for propagation of constraints may be created. Those files can give the morphing operations greater flexibility. Propagation of constraints can regard the geometry of a model, solar shadings, mass/flow network, controls, and generic text files descripting a simulation model.

The simulation model folders and the result files that will be created in a parametric search will assigned a unique name base on a sequence, but within the program each instance will be assigned a name consituted by numbers describing the position of the instance in the multidimensional matrix (tensor). For example, within the program, the instance produced in the first iteration for a root model named "model" in a search constituted by 3 morphing phases and 5 iteration steps each would be named "model_1-1_2-1_3-1"; and the last one, "model_1-5_2-5_3-5"; while the file may be named "model_1__" and "model_128__". After each program's run, the correspondence between the file names and the instance names is recorded in a file ending with "_cryptolinks.pl"; and there is also an option to keep the file names unencrypted (which can be done if they are not too long).

The structure of the block searches in the configuration file is described through the variable "@sweeps". Each case is listed inside square brackets; and each search subspace (block) in each case is listed inside square brakets. For example: a sequence constituted by two sequential full-factorial force searches, one regarding parameters 1, 2, 3 and the other regarding parameters 1, 4, 5, 7, would be described with: @sweeps = ( [ [ 1, 2, 3 ] ] , [ [ 1, 4, 5, 7 ] ] ) . And a sequential block search with the first subspace regarding parameters 1, 2, 3 and the second regarding parameters 3, 4, 5, 6 would be described with: @sweeps = ( [ [ 1, 2, 3 ] , [ 3, 4, 5, 6 ] ] ).

The number of iterations to be taken into account for each parameter for each case is specified in the "@varnumbers" variable. To specifiy that the parameters of the last example are to be tried for three values (iterations) each, @varnumbers has to be set to ( { 1 => 3, 2 => 3, 3 => 3, 4 => 3, 5 => 3, 6 => 3 } ).

The instance number that has to trated as the basic instance, corresponding to the root case, is specified by the variable "@miditers". "@miditers" for the last example may be for instance set to ( { 1 => 2, 2 => 2, 3 => 2, 4 => 2, 5 => 2, 6 => 2 } ).

OPT can work on a given set of pre-simulated results without launching new simulations, and it can randomize both the sequence of the search and the initialization level of the parameters (see the included examples).

By default the behaviour of the program is sequential. To make it parallel locally, subspaces have to be named with a name not containing numbers, so as to work as a collector cells. If the name "name", for example, has to be given to a block, the letters "name" must be joined at the beginning of the first number describing an iteration number in a block. If that number is 1, for example, the first element of that block should be named "name1". As an effect, that block will receive values from all the blocks "pointing" to the name "name". To point the search outcome of a block to another block, the name of the block pointed to has to be appended to the last number describing an iteration number in a block. If, for example, that number is 3 and the name of the block pointed to is "surname", the last element of that block should be named "3surname". A block of in which both the mentioned situations took place could be named [ "name1", 2, "3surname" ].

If the search is to start from more than one block in parallel, the first block should be named and all the other starting blocks should be named like it.

The capability of articulating a mix of parallel and sequential searches is of absolute importance, because it makes possible to design search structures with a "depth", embodying precedence, and therefore procedural time, in them. This toolset is needed to describe directed graphs.

OPT can perform star searches (Jacoby method of course, but also Gauss-Seidel) within blocks in place of multilevel full-factorial searches. To ask for that in a configuration file, the first number in a block has to be preceded by a ">" sign, which in its turn has to be preceded by a number specifying how many star points there have to be in the block. A block, in that case, should be declared with something like this: ( "2>1", 2, 3). When operating with pre-simulated dataseries or metamodels, OPT can also perform: factorial searches (to ask for that, the first number in that block has to be preceded by a "<" sign); face-centered composite design searches of the DOE type (in that case, the first number in the block has to be preceded by a "£"); random searches (the first number has to be preceded by a "|"); latin hypercube searches (the first number has to be preceded by a "§").

For specifying in a Sim::OPT configuration file that a certain block has to be searched by the means of a metamodel derived from star searches or other "positions" instead of a multilevel full-factorial search, it is necessary to assign the value "yes" to the variable $dowhat{metamodel}.

OPT can perform both variance-based sensitivity analyses on the basis of simulated dataseries and variance-based preliminary sensitivity analyses on the basis of metamodels.

OPT works under Linux.

EXPORT

"opt".

SEE ALSO

Annotated examples (which include "esp.pl" for ESP-r, "ep.pl" for EnergyPlus - the two perform the same morphing operations on models describing the same building -, "des.pl" about block search, and "f.pl" about a search in a pre-simulated dataset, and other) can be found packed in the "optw.tar.gz" file in "examples" directory in this distribution. They constitute all the available documentation besides these pages and the source code.

AUTHOR

Gian Luca Brunetti, <gianluca.brunetti@polimi.it>

COPYRIGHT AND LICENSE

Copyright (C) 2008-2018 by Gian Luca Brunetti and Politecnico di Milano. This is free software. You can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 3.