Python Usage

Quickstart script

Besides the viasp command line tool, viASP can also be run from a simple python scripts. Note that both the server and the client need to be started and initialized by the script at each use.

A custom script has the advantage of closer control over the program flow and the ability to fully use viASP’s python API.

Run the script at examples/quickstart.py to start viASP with a given encoding.

$ python quickstart.py encoding.lp

Extending arbitrary python scripts

To use viASP in your own python scripts using the clingo API, you can use the viASP python API or the viASP Control proxy object. The following code snippets show how to use the viASP Control proxy object:

To start the viASP server:

from viasp.server import startup
app = startup.run()

Replace the clingo.Control object with the viasp.Control proxy object:

from viasp import Control
options = ['0']
ctl = Control(options)

The Control proxy behaves exactly like the clingo Control object, but additionally provides some viASP-specific methods.

Mark stable models for visualization:

with ctl.solve(yield_=True) as handle:
for m in handle:
    ctl.viasp.mark(m)

Start the graph generation:

ctl.viasp.show()

Finally, launch the graph visualization:

app.run()

Example

In this example, all of these snippets are combined into a script using the viASP Control proxy and the clingo Application

from clingo.application import clingo_main, Application
from viasp import Control

class App(Application):

    def main(self, ctl, files):
        ctl = Control(control=ctl, files=files)

        for path in files:
            ctl.load(path)
        ctl.ground([("base", [])])
        with ctl.solve(yield_=True) as handle:
            for m in handle:
                ctl.viasp.mark(m)
            print(handle.get())
        ctl.viasp.show()


if __name__ == "__main__":
    clingo_main(App(), ['0', 'encoding.lp'])
    app.run_server()