General Purpose Design of Experiment

Successful installation of gsa-module will give access to two executables in the path useful to create various designs for computer experiment. The command line utility gsa_create_sample can be invoked from the terminal to generate the design (or design matrix file) using the following command:

> gsa_create_sample -n <number of samples/points> \
                    -d <number of dimensions/variables> \
                    -m <method of generation {srs, lhs, sobol, lhs-opt}> \
                    -s <random seed number> \
                    -o <design matrix output filename> \
                    -sep <delimiter for the design matrix file> \
                    -dirnumfile <direction number file, Sobol' only> \
                    -excl_nom <exclude nominal file, Sobol' only> \
                    -rand <randomize the Sobol' sequence, Sobol' only> \
                    -nopt <number of optimization iterations, Sobol' only>

Brief explanation of these parameters can be shown by invoking:

> gsa_create_sample --help

The table below lists the complete options/flag in detail with their respective default values.

No.	Short Name	Long Name	Type	Required	Description	Default
1	-h	–help	flag	No	Show help message	False
2	-n	–num_samples	integer	Yes	The number of samples/design points	None
3	-d	–num_dimensions	integer	Yes	The number of dimensions	None
4	-m	–method	string	No	The method to generate sample {srs, lhs, sobol, lhs-opt}	srs
5	-s	–seed_number	integer	No	The random seed number	None
6	-o	–output_file	string	No	The output filename	see below
7	-sep	–delimiter	string	No	The delimiter for the file {csv, tsv, txt}	csv
8	-dirnumfile	–direction_numbers	string	No	The path to Sobol’ sequence generator	None
9	-excl_nom	–exclude_nominal	flag	No	Exclude the nominal point {0.5} in the design	False
10	-rand	–randomize_sobol	flag	No	Random shift the Sobol’ sequence	False
11	-nopt	–num_iterations	integer	No	The maximum bumber of optimization iterations	100
12	-V	–version	flag	No	Show the program’s version number and exit	False

Note that options number 8-9 are valid only for Sobol’ design, while option number 11 is valid only for Optimized LHS. Without specifying the output filename explicitly, the design matrix file will be produced with the following naming convention:

> <method>_<num_samples>_<num_dimensions>.csv

Example

For example, upon executing the following command in the terminal:

> gsa_create_sample -n 20 -d 5 -m sobol

a csv file with filename sobol_20_5.csv is produced in the current working directory. The first 5 lines (out of 20) the file are as follow:

0.000000e+00,0.000000e+00,0.000000e+00,0.000000e+00,0.000000e+00
5.000000e-01,5.000000e-01,5.000000e-01,5.000000e-01,5.000000e-01
7.500000e-01,2.500000e-01,2.500000e-01,2.500000e-01,7.500000e-01
2.500000e-01,7.500000e-01,7.500000e-01,7.500000e-01,2.500000e-01
3.750000e-01,3.750000e-01,6.250000e-01,8.750000e-01,3.750000e-01

In each line, the listed values correspond to the input parameters at which the model is to be evaluated. The values are normalized between 0 to 1.