[GSLL-devel] [Gsll-devel] Efficient access to externally generated double-float arrays?

[Liam Healy]

On Sun, Nov 14, 2010 at 10:24 AM, Sebastian Sturm
<Sebastian.Sturm at itp.uni-leipzig.de> wrote:
> My apologies for taking so long to answer. I have verified that the new gref* can now be used without consing and comes relatively close to the unconvenient cffi:mem-aref solution in terms of computation time. Many thanks for that! I also tried the functions on matrices, which still results in some consing, but this doesn't seem to be time-critical here. In my experiments, most of the consing could be eliminated by storing the linearized index in an auxiliary variable, but this even resulted in a slight runtime increase.
> For my original application, the GSLL solution is now comparable in speed to Mathematica for small dimensionality (dim < about 50); for a fair comparison of both solutions for larger dim, I'll have to rework my very naive computation of the Hessian matrix.
>
> Judging from the git commits, you have also changed something related to complex-valued arrays. Did you implement similar optimizations as in the real-valued case? I'll try that once I have repaired my Hessian.
>
> Best regards,
> Sebastian

The work is still ongoing.  I don't know when you last pulled, but
I've made a few commits in the last day or so, and I'm working on some
more improvements.  My previous email was incorrect in stating that
the 'declare form doesn't work; it does at least in newer versions of
SBCL.  Also, I've expanded use to CCL because that supports
variable-information as well (this hasn't been committed yet).   The
other recent change is that inputs and outputs of gref* and (setf
gref*) are now wrapped with the appropriate 'the forms to help the
compiler optimize.   So far these mostly apply only to vectors (1
dimensional arrays) but I am working on compile-time linearization of
indices for higher dimensional arrays, so that at compile time the
forms will also expand directly into mem-aref calls; that should help
with your matrices if they are declared with their dimensions.  I'm
working on this now.   Everything should apply to all foreign array
types, including complex.

Liam