Disable modules at compile-time or runtime

edit

Since you are compiling Sage on a powerful virtual machine, i would advise not touching the build system, just not to lose your time. If you absoluely want to do that, you can disable the compilation of some standard packages by declaring them optional (for this, you will have to edit the fiie SAGE_ROOT/build/pkgs/<package>/type for each <package>, and run ./configure again), but you will experience a lot of issues (unsatisfied dependencies). Some simple removals are doable (e.g. removing both r and ryp2).

Now, if you speak about runtime, you can remove some automatic imports at startup. The Sage modules are imported in SAGE_ROOT/src/sage/all.py, and it recursively calls the contents of SAGE_ROOT/src/sage/<module>/all.py for each <module>.

By the way, i would be interested to see how you deploy your build infrastructure (i personaly have some hand-made build system that is used to build some specific 32bit patchbots, Sage Dabian Live (and a bunch of Sage binaries a few years ago), and i was thinking whether it is worth cleaning them and why not extend them to build such weird images, hence i would be glad to see your approach).

For your needs, you could also try to just install sympy and run it from a jupyer notebook (probably both distributed from your distro).

Making Sage more modular is on the roadmap and will make what you ask easier in the future, but it's not there yet. Besides removing R and RPy2 as @tmonteil suggests, I don't see any easy targets.

Below is a list (edited 2018-10-25) of more lightweight software in case SageMath takes too much space for your needs.

In the same spirit as the suggestion by @tmonteil to consider using

• SymPy and Jupyter, (see also symengine),

consider also

• Paul Masson's MathCell, developed as a lightweight replacement for SageCell to power the website Analytic Physics.

or, as suggested by @Loveless,

• Bernard Parisse's giac/libgiac and Frederic Han's GiacPy,

or the recently revived:

• Python-FLINT (Python bindings for FLINT and Arb), by Fredrik Johansson, who in the announcement of the latest revival, explains that

  The goal is to have a Python wrapper for Flint and Arb that is just a standalone and lightweight Python module, no multi-gigabyte Sage installation required. Also, the user doesn't have to construct parent rings, so the interface is more convenient for quick calculations.