[gmx-developers] mknb doesn't work on BlueGene with --enable-ppc-sqrt in single precision
lindahl at cbr.su.se
Thu Sep 3 19:07:46 CEST 2009
On Sep 3, 2009, at 3:18 AM, Roland Schulz wrote:
> I fixed it in the release branch (thus it will be in 4.0.6).
> How is one supposed to change the kernels in the head branch? Is
> there some script to generate the generic kernels? The output of
> mknb -fortran --ppc_invsqrt is different than what is in
> nb_kernel_power6. So changing something in nb_kernel_power6 requires
> to change each file?
Uhm... I *think* I generated them with the mknb, but I might have
changed something in the generator since.
One of the main reasons for abandoning mknb is that it should at least
be possible to implement a new interaction by simply copying-and-
changing a routine, rather than first having to understand a stupid
meta-language. So, while we could of course try to extend/modify it,
that would just put us back in the same position if all changes *have*
to be incorporated in mknb.
While it's a neat idea to have a single generator to write exactly the
code we need for every single architecture, it will probably turn into
a maintenance nightmare in the long run, in particular since the
present version of mknb is a horrible hack I wrote years ago. I'd be
quite interested in good suggestions, in particular since we're
preparing an overhaul of the nonbonded kernels to enable more features
like analytic switch/shift, kernels that only compute potentials
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