Libint on Ubuntu only supports L=4

[JensWehner]

Whereas fedora, opensuse and gentoo packages support up to L=6

So updating the ubuntu package would be nice.

[junghans]

@mbanck is that something we could add in the debian package?

[junghans]

ping @mbanck

[mbanck]

Do you have patch, or the configure options that are required?

[JensWehner]

We build our local version with --disable-shared --with-pic --enable-eri2 --enable-eri3 --with-max-am=6

[junghans]

Here are fedora’s configure options: https://src.fedoraproject.org/rpms/libint2/blob/master/f/generate-sources.sh#_45

[mbanck]

Hrm, so --enable-eri2 is the same as --enable-eri2=0 from looking at configure.ac, or what would it correspond to, seeing that Fedora seems to do --enable-eri2=2 (and lot of others)?

[JensWehner]

the number should indicate which derivatives are provided for that type of integral

[mbanck]

So what's the real-world benefit in going from 4 to 6, seeing how it blows up the build time (and likely library size) by a lot? What kind of computations/simulations will be possible that are currently not?

[JensWehner]

@mbanck So in quantum chemistry basisfunctions are labelled according to their angular momentum. Typically basisfunctions for light elements go up to g(l=4) functions, for heavier elements (3rd row+) higher functions are used. Also often auxiliary basissets are used which routinely go up to i(l=6). Also the derivatives of basisfunctions are used a lot for geometry optimisations of molecules. So the current debian/ubuntu config is basically only useful for unittesting and toy systems. The fedora config can be used in most production settings. The disadvantage obviously is, that the build times go up quite dramatically.

So I would argue the fedora config coves 90% of all usecases, whereas the debian config is like 20-30%.

Also see evaleev/libint#190

Thank you for your help.

[mbanck]

I've uploaded libint2 with l=5 for now, let's see whether the autobuilders cope, I'll bump it to 6 if there's no issues.

[mbanck]

I've bumped it to l=6 now, and the autobuilders have been building it for 24 hours and counting.

[JensWehner]

I am starting to see your point.