On Tuesday, 9 June 2015 at 16:18:06 UTC, Manu wrote:
On 10 June 2015 at 01:26, Ilya Yaroshenko via Digitalmars-d
<[email protected]> wrote:
I believe that Phobos must support some common methods of
linear algebra and general mathematics. I have no desire to
join D with Fortran libraries :)
D definitely needs BLAS API support for matrix multiplication.
Best BLAS libraries are written in assembler like openBLAS.
Otherwise D will have last position in corresponding math
benchmarks.
A complication for linear algebra (or other mathsy things in
general)
is the inability to detect and implement compound operations.
We don't declare mathematical operators to be algebraic
operations,
which I think is a lost opportunity.
If we defined the properties along with their properties
(commutativity, transitivity, invertibility, etc), then the
compiler
could potentially do an algebraic simplification on expressions
before
performing codegen and optimisation.
There are a lot of situations where the optimiser can't simplify
expressions because it runs into an arbitrary function call,
and I've
never seen an optimiser that understands exp/log/roots, etc, to
the
point where it can reduce those expressions properly. To
compete with
maths benchmarks, we need some means to simplify expressions
properly.
Optimising floating point is a massive pain because of precision
concerns and IEEE-754 conformance. Just because something is
analytically the same doesn't mean you want the optimiser to go
ahead and make the switch for you.
Of the things that can be done, lazy operations should make it
easier/possible for the optimiser to spot.
