Re: GLPSOL in webassemby faster than native ?

[Domingo Alvarez Duarte]

Hello Andrew !

In this case mean compiling with "-O3 -DNDEBUG -DWITH_SPLAYTREE" on 
Arm7, "-O3 -DNDEBUG -flto -march=native -ffp-contract=off 
-DWITH_SPLAYTREE" on x86_64 and "-O3 -DNDEBUG -flto -DWITH_SPLAYTREE" on 
wasm.

How are the parameters for the cut generations selected ?

Isn't strange that on wasm it's been faster than native ?

Doesn't this difference gives insight to select the parameter differently ?

Cheers !

On 22/9/20 17:56, Andrew Makhorin wrote:
> On Tue, 2020-09-22 at 15:53 +0200, Domingo Alvarez Duarte wrote:
> > Hello again !
> >
> > On an Android phone arm7 32bits Nexux-5 with chrome browser (wasm)
> > solving the "hashi.mod" with "--cuts" takes 98s and without it 909s,
> > using glpsol native compiled within termux takes 497s with "--cuts"
> > and
> > without it 925s.
>
> What does "native" mean? Just changing, for example, optimization level
> of the compiler may essentially change the set of generated cuts and
> thus the solution time.
>
>
> > Arm7 32bits Nexus-5:
> >
> >       wasm "--cuts -m hashi.mod" -> 98s
> >
> >       wasm " -m hashi.mod" -> 909s
> >
> >       native "--cuts -m hashi.mod" -> 497s
> >
> >       native " -m hashi.mod" -> 925s
> >
> >
> > Laptop Linux 64bits I7:
> >
> >       wasm "--cuts -m hashi.mod" -> 8s
> >
> >       wasm " -m hashi.mod" -> 142s
> >
> >       native "--cuts -m hashi.mod" -> 73s
> >
> >       native " -m hashi.mod" -> 55s
> >
> >
> > On arm7 "--cuts" improves the performance in both wasm and native.
> >
> > On x86_64 "--cuts" improves in wasm but degrade in native.
> >
> > I hope this could give hints to improve GLPK solver performance by
> > inspecting the decision's criteria and eventually find a better ones.
> >
> > Anyone can give any idea with this data ?
> >
> > Cheers !
> >
> > On 21/9/20 17:11, Andrew Makhorin wrote:
> > > On Mon, 2020-09-21 at 16:09 +0200, Domingo Alvarez Duarte wrote:
> > > > Hello Andrew !
> > > >
> > > > Are you saying that floating point calculations are more
> > > > efficient/precise in webassembly ?
> > > No. I meant that due to floating-point computations running the same
> > > computer program with the same data as a rule produces different
> > > results
> > > on different platforms.
> > >
> > > > Cheers !
> > > >
> > > > On 21/9/20 15:08, Andrew Makhorin wrote:
> > > > > > Does someone can give a possible explanation ?
> > > > > floating-point computations