OK, I've now committed what I think is my last attempt at this. This
latest version includes optimization of matrices and setting values in
foreign arrays. This latter comes with a caveat however. The
compiler will macroexpand setf, and for SBCL at least, that means
making temporary variables to
On Sun, Nov 14, 2010 at 10:24 AM, Sebastian Sturm
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
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 s
OK, this turned out to be a lot harder than I thought. I have done
three things:
1) I have defined gref* and (setf gref*) methods specific to each of
the foreign-array types that call cffi:mem-aref. This gives about 20x
speedup because I am now passing the literal type to cffi:mem-aref, so
it can
Liam,
I'm sorry, I now see a difference between the original gref* and your modified
version of it. I guess I forgot to reload the Lisp image last time, so both
timings had been obtained using the new gref*. There is still consing, but it's
already reduced by a factor of three. Can be reduced b
Sebastian,
Trying to walk code correctly is a nasty business, and generally
non-portable, so I'd stay away from it. We could do this with a
macro/macrolet pair but I'd like to optimize via the CLOS route if we
can.
Liam
On Thu, Oct 28, 2010 at 1:01 PM, Sebastian Sturm
wrote:
> Here is somethi
Sebastian,
I'm very puzzled by this. You should now have the type :double
hard-wired in the CFFI call. Can you run your big test with and
without this function defined, instead of just the grid:gref* test?
If it still shows no improvement, that says that the problem is not in
the binding of type
Here is something similar to what I suggested, although still very unfinished.
It's probably not the proper way to write a macro, but I guess other people on
the list will know how to do it correctly. Efficient linearization can be added
in the same manner; also, the macro should be modified s.t
Liam,
I have tried this and (without using (the double-float (...)) since this is
unnecessary for cffi:mem-aref with hardcoded :double data type), I get the
following timing data:
using the standard grid:gref routine:
Evaluation took:
0.542 seconds of real time
0.536671 seconds of total run tim
Sebastian,
Can you temporarily define this and find the timing/consing for your
test case:
(defmethod gref* ((object vector-double-float) linearized-index)
(cffi:mem-aref
(foreign-pointer object)
:double
linearized-index))
(I think you don't use any matrices but if you do, define an a
On Fri, Oct 22, 2010 at 2:13 PM, Sebastian Sturm
wrote:
>> I'm surprised about the grid:gref result. Please run a profiler and
>> confirm that the time consumed is within grid:gref and its callees,
>
> I tried using sb-sprof, but as a complete CL newbie I had a hard time making
> sense of its o
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