Welcome to GDX2py’s documentation!¶
GDX2py is a Python package providing read and write support for GAMS GDX files using built-in data types list and dictionary.
Contents:
Usage¶
GdxFile objects behave like dictionaries.
>>> from gdx2py import GdxFile, GAMSSet, GAMSScalar, GAMSParameter
>>> with GdxFile('/path/to/gdx/file.gdx', mode='w') as gdx:
>>> gdx['set1'] = ['a', 'b', 'c'] # Write a simple set
>>> set1 = gdx['set1'] # Read a symbol
>>> # Write a 2-dimensional set
>>> gdx['set2'] = [('a', 'foo'), ('b', 'bar'), ('c', 'baz')]
>>> # Write a scalar with explanatory text
>>> pi = GAMSScalar(3.14, expl_text="Value of pi")
>>> gdx['pi'] = pi
GAMS symbol objects¶
The symbol returned is either a GAMSSet, GAMSParameter or
GAMSScalar. You can convert them to Python built-ins.
>>> float(pi)
3.14
>>> list(set1)
['a', 'b', 'c']
>>> par = GAMSParameter({'a': 1, 'b': 2, 'c': 3, 'd': 4 })
>>> dict(par)
{'a': 1, 'b': 2, 'c': 3, 'd': 4 }
Symbol domains¶
GAMS sets and parameteres can also have a domain. Use the optional domain
parameter to the constructor to define the domain.
>>> cats = GAMSSet(['jaguar', 'lion', 'tiger'], domain=['animals'])
The universal set (‘*’ in GAMS) means there is no specific domain.
Use None for the universal set.
>>> set2d = GAMSSet([('a', 'foo'), ('b', 'bar'), ('c', 'baz')], domain=['abc', None])