Second Singular GAP developers meeting (Kaiserslautern)

The second Singular-GAP developers meeting (14-18.11.2011, Kaiserslautern)

Welcome to the second Singular-GAP developers meeting.

Participants:

• Mohamed Barakat (University of Kaiserslautern)
• Reimer Behrends (University of St Andrews)
• Christian Eder (University of Kaiserslautern)
• Max Horn (Braunschweig University)
• Alexander Konovalov (University of St Andrews)
• Martin Lee (University of Kaiserslautern)
• Frank Lübeck (RWTH Aachen University)
• Oleksandr Motsak (University of Kaiserslautern)
• Max Neunhöffer (University of St Andrews)
• Hans Schönemann (University of Kaiserslautern)
• Andreas Steenpaß (University of Kaiserslautern)

This is to describe the current state of affairs of the GAP package libsingular, mostly as a preparation for the next week in Kaiserslautern.

What works?

• Compile libsigular and the GAP package, run GAP, load the package
• The two memory management schemes coexist peacefully within the same process.
• Call the Singular interpreter from GAP giving it a string to evaluate. (Singular output is collected in a string).
• Read variables in the Singular interpreter and return their values to GAP. (For the moment, integers, intvecs, intmats and strings are supported).
• Define a singular polynomial ring from GAP, access its indeterminates. (The ring is represented by a GAP object which references the Singular object.)
• Define monomials in that ring. (Polynomials are represented by GAP objects which reference the Singular object.)
• Add and multiply polynomials, multiply polynomials with scalars.
• Transform a singular polynomial to a string.

What does not yet work?

• Handling of errors occurring in the Singular interpreter
• Writing to Singular variables from GAP
• Polynomial rings with monomial ordering (no fundamental problem visible, just not yet implemented)
• Other Singular data types represented by GAP objects
• More arithmetic operations for polynomials
• There are not yet nice methods installed in GAP using + and * for polynomials.
• Lots more...

Questions (to be discussed next week):

• How to handle errors occurring in the Singular interpreter?
• What Singular data types are to be represented in GAP, for example, do we need "number" or do we use GAP's numbers instead?
• Is the "current ring" issue in Singular addressed properly?
• Does the memory management actually work when stressed?
• Are there possible memory leaks?
• Do we have any performance issues?

Future directions:

• Provide everything Mohamed needs for homalg using the integrated libsingular.
• Implement access to more of Singular's features.
• Make sure that it is viable to implement higher level algorithms in the GAP language using libsingular objects.
• Integration of the Singular objects in GAP's object zoo.

What to do next week?

• Discuss the above questions and possibly others.
• Discuss the future directions.
• Solve technical problems.
• Move on with the implementation.
• Discuss libsingular with a view to the upcoming parallelized GAP (HPCGAP).