Command Line Usage

Basic command line usage

Most of the features available in basic usage are also available using command line. Running:

python -m pysd Teacup.mdl

will translate Teacup.mdl to and run it with the default values. The output will be saved in The command line accepts several arguments, this can be checked using the -h/–help argument:

python -m pysd --help

Set output file

In order to set the output file -o/–output-file argument can be used:

python -m pysd -o my_output_file.csv Teacup.mdl


The output file can be a .csv or .tab.


If -o/–output-file is not given the output will be saved in a file that starts with the model file name and has a time stamp to avoid overwritting files.

Activate progress bar

The progress bar can be activated using -p/–progress command:

python -m pysd --progress Teacup.mdl

Translation options

Only translate model file

To only translate the model file, it does not run the model, -t/–trasnlate command is provided:

python -m pysd --translate Teacup.mdl

Splitting Vensim views in different files

In order to split the Vensim model views in different files as explained in advanced usage:

python -m pysd --split-modules many_views_model.mdl

Outputting various run information

The output number of variables can be modified bu passing them as arguments separated by commas, using -r/return_columns argument:

python -m pysd -r 'Teacup Temperature, Room Temperature' Teacup.mdl

Note that the argument passed after -r/return_columns should be inside ‘’ to be properly read. Moreover each variable name must be split with commas.

Sometimes, the variable names have special characteres, such as commas, which can happen when trying to return a variable with subscripts. In this case whe can save a .txt file with one variable name per row and use it as an argument:

python -m pysd -r output_selected_vars.txt Teacup.mdl

-R/–return-timestamps command can be used to set the return timestamps:

python -m pysd -R '0, 1, 3, 7, 9.5, 13.178, 21, 25, 30' Teacup.mdl


Each time stamp should be able to be computed as initial_time + N x time_step, where N is an integer.


The time outputs can be also modified using the model control variables, explained in next section.

Modify model variables

Modify model control variables

The model control variables such as the initial time. final time, time step and saving step can be easily modified using the -I/–initial_time, -F/–final-time, -T/–time-step and -S/–saveper commands respectively. For example:

python -m pysd -I 2005 --final-time=2010 --time-step=1 Teacup.mdl

will set the initial time to 2005, the final time to 2010 and the time step to 1.


If -R/–return-timestamps argument is used the final time and saving step will be ignored.

Modify model variables

In order to modify the values of model variables they can be passed after the model file:

python -m pysd Teacup.mdl 'Room Temperature'=5

this will set Room Temperature variable to the constant value 5. A series can be also passed to change a value of a value to a time dependent series or the interpolation values of a lookup variable two lists of the same length must be given:

python -m pysd Teacup.mdl 'Temperature Lookup=[[1, 2, 3, 4], [10, 15, 17, 18]]'

The first list will be used for the time or x values and the second for the data. See setting parameter values in basic usage for more information.


If a variable name or the right hand side are defined with whitespaces it is needed to add ‘’ define it, as has been done in the last example.

Several variables can be changed at the same time, e.g.:

python -m pysd Teacup.mdl 'Room Temperature'=5 temperature_lookup='[[1, 2, 3, 4], [10, 15, 17, 18]]' 'Initial Temperature'=5

Modify initial conditions of model variables

Sometimes we do not want to change a variable value to a constant but change its initial value, for example change initial value of a stock object, this can be similarly done to the previos case but using ‘:’ instead of ‘=’:

python -m pysd Teacup.mdl 'Teacup Temperature':30

this will set initial Teacup Temperature to 30.

Putting It All Together

Several commands can be used together, first need to add optional arguments, those starting with ‘-’, next the model file, and last the variable or variables to change, for example:

python -m pysd -o my_output_file.csv --progress --final-time=2010 --time-step=1 Teacup.mdl 'Room Temperature'=5 temperature_lookup='[[1, 2, 3, 4], [10, 15, 17, 18]]' 'Teacup Temperature':30

will save step 1 outputs until 2010 in my_output_file.csv, showing a progressbar during integration and settung foo to 5 and temperature_lookup to ((1, 10), (2, 15), (3, 17), (4, 18)) and initial Teacup Temperature to 30.