[needs-packaging] Please provide a development version of atlas alongside stable

[Sergio Callegari]

Utopic is going to include atlas 3.10.2. So far so good, since this is the stable version.

However, this is what the very developer of atlas says:

      3.10.2 is terribly out of date, and was released only because the
      threading rewrite it taking too long.

      If possible, *you should use a
      developer release* after testing that it works for your particular
      platform.

      In particular, developer releases are *much* faster for any
      x86 that uses AVX or later SIMD ISA, or any machine with ncores >= 8.

As a matter of fact, the stable atlas is simply terrible on any recent cpu, and primarily on haswell.

In fact, ubuntu (just like debian) ships an unoptimized version of atlas and then suggests
rebuilding for your specific architecture in order to get an optimized version.
Unfortunately, atlas 3.10.x does not seem to include any sensible architectural default for haswell.
This means that:
- rebuilding for haswell takes a *huge* amount of time (in the order of a day)
- the result is still often insatisfactory.

As a result, the shipped version of atlas ends up being bad suited specifically to those users who
acquired recent fast multicore machines precisely with the purpose of doing efficient number
crunching.

Consequently, I would like to suggest providing atlas 3.11.x alongside 3.10.x for those users willing
to use the devel version *like the authors suggests*. This would end up being similar to what is done
with other packages (e.g. emacs has been provided for long in different flavours emacs23 and emacs24).

[Brian Murray (brian-murray)]

*** This is an automated message ***

This bug is tagged needs-packaging which identifies it as a request for a new package in Ubuntu. As a part of the managing needs-packaging bug reports specification, https://wiki.ubuntu.com/QATeam/Specs/NeedsPackagingBugs, all needs-packaging bug reports have Wishlist importance. Subsequently, I'm setting this bug's status to Wishlist.

[Sergio Callegari (callegar)]

As of ubuntu vivid it is not possible anymore to build custom atlas packages at all on modern Intel CPUs.

The 3.10.x build script sees that the system is capable of cpu throttling and aborts.

However modern Intel CPU default to the p-state driver for which the throttling cannot be disabled.

[Sergio Callegari (callegar)]

This is a serious impairment to using atlas, so please rise priority to bug from whishlist.

[Sergio Callegari (callegar)]

Looks like it is now completely impossible to custom build atlas following the provided README.Debian instructions, on cpus using the p-state driver because of obsolete build scripts.
Working around the issue is relatively easy, though.

[Sergio Callegari (callegar)]

Should I open a new bug on this?