First steps --- libsemigroups_pybind11

Now that you've successfully installed libsemigroups_pybind11, this page explains a few ways to start using it; see Installation.

If you are familiar with Jupyter notebooks and/or are comfortable with using the Python interpreter, then you can skim this page and continue with the examples in the rest of the tutorial.

This guide assumes you are familiar with programming in Python, if you are not, then take a look at Software Carpentry Programming With Python

Using IPython in a terminal

The terminal is an application where you can type commands. The name of the terminal application depends on your operating system:

on macOS, open Terminal;
on Linux, open the terminal application provided by your desktop environment.

If you installed libsemigroups_pybind11 in a conda or mamba environment, first activate that environment:

$ mamba activate libsemigroups_pybind11

If you chose a different environment name during installation, use that name instead.

Next start IPython:

$ ipython

You should now see a prompt beginning with In [1]:. Import libsemigroups_pybind11 as follows:

import libsemigroups_pybind11

You can also import the particular classes and functions you want to use:

from libsemigroups_pybind11 import FroidurePin, Transf

For example:

f = Transf([1, 0])
g = Transf([0, 0])
S = FroidurePin([f, g])
S.size()

To leave IPython, type:

exit

or press Ctrl-D.

Using a local Jupyter notebook

A Jupyter notebook is often more convenient than a terminal session because you can keep code, output, notes, and plots together in one place.

If you installed libsemigroups_pybind11 in a conda or mamba environment, activate it first:

$ mamba activate libsemigroups_pybind11

Then start Jupyter:

$ jupyter notebook

This should open Jupyter in your web browser. Create a new notebook and type the following into the first code cell:

import libsemigroups_pybind11

Run the cell. If it finishes without an error, then the notebook can see your installation of libsemigroups_pybind11.

You can use the same imports as in IPython:

from libsemigroups_pybind11 import FroidurePin, Transf

S = FroidurePin([Transf([1, 0]), Transf([0, 0])])
S.size()

When you have finished, choose File > Save and Checkpoint in Jupyter, then stop the notebook server from the terminal by pressing Ctrl-C.

Using an online notebook service

You can also use a notebook service that runs Python in a web browser. This is useful if you cannot install software on your own computer, or if you want to share a notebook with someone else. Examples include Google Colab, Binder, CoCalc, and hosted JupyterLab services.

The details differ from service to service, but the general idea is:

Create a new Python notebook.
Install libsemigroups_pybind11 in the notebook.
Import libsemigroups_pybind11 in a later cell.

For services that allow pip installs from a notebook cell, the first cell can usually be:

%pip install libsemigroups_pybind11

After that cell has finished, run:

import libsemigroups_pybind11

or:

from libsemigroups_pybind11 import FroidurePin, Transf

Some services reset the Python environment when the notebook is closed. If that happens, run the installation cell again the next time you open the notebook.

Hosted notebook services may use different Python versions or operating systems from your own computer. If pip install libsemigroups_pybind11 fails on one service, try running the notebook locally, or use a service that supports conda/mamba environments.

Checking that the import worked

In IPython, a local notebook, or an online notebook, a successful import usually prints nothing. To check that Python has found the package, you can run:

import libsemigroups_pybind11
dir(libsemigroups_pybind11)

This should print a list of names provided by libsemigroups_pybind11.