Subject: [FFC-dev] Optimized FFC code?

From: "Martin Sandve Alnæs" <[email-masked]>
Date: Tue, 16 Oct 2007 15:32:42 +0200

In the FFC manual it says that --optimize is currently ignored, does
this mean that optimization isn't working at all at the moment?

We're doing benchmarks of sfc vs ffc vs dealII vs diffpack, and ffc
isn't doing as well as I expected.

--
Martin

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From: "Garth N. Wells" <[email-masked]>
Date: Tue, 16 Oct 2007 14:37:51 +0100

> this mean that optimization isn't working at all at the moment?

It means that FErari isn't being used.

> isn't doing as well as I expected.

Are you looking at just assembly?

Garth

> --
> Martin
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From: "Martin Sandve Alnæs" <[email-masked]>
Date: Tue, 16 Oct 2007 15:41:04 +0200

> It means that FErari isn't being used.

When will it be reimplemented then?

> Are you looking at just assembly?

Just computing the element tensor. (We'll do full assembly too later.)

--
Martin

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From: "Martin Sandve Alnæs" <[email-masked]>
Date: Tue, 16 Oct 2007 16:34:30 +0200

Sorry, didn't look at the generated code. FFC is generating quadrature
code, I thought the default argument quadrature_points=False to jit
options meant tensor representation. How do I choose tensor
representation with jit?

-- 
Martin

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From: Kristian Oelgaard <[email-masked]>
Date: Tue, 16 Oct 2007 16:51:20 +0200

> options meant tensor representation. How do I choose tensor

I thought FFC was using tensor representation by default? The quadrature_points
option can be used to specify how many quadrature points are used if one
compiles using the quadrature representation.

Kristian

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From: "Garth N. Wells" <[email-masked]>
Date: Tue, 16 Oct 2007 15:57:57 +0100

> compiles using the quadrature representation.

Anders might have set quadrature as default for JIT as it compiles 
faster than the quadrature representation.

Garth

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From: "Martin Sandve Alnæs" <[email-masked]>
Date: Tue, 16 Oct 2007 17:11:25 +0200

> compiles using the quadrature representation.

The problem was partly me not reading the fine manual, and partly jit
seemingly not doing any error checks on the input. I just did
jit(form, options) which should've given an error message.

If everything goes well tonight, I'll have some benchmark results
tomorrow. It seems the performance of ffc and sfc is fairly close in
most cases.

--
Martin

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From: Anders Logg <[email-masked]>
Date: Tue, 16 Oct 2007 17:09:15 +0200

> faster than the quadrature representation.

Not that I know of, but we should keep this in mind if we want to
reduce the compile times.

I just double-checked and we generate code by tensor-representation in
the jit compiler (if not otherwise specified).

Martin, are you using any special options to jit()?

And are you sure you get quadrature code?

/Anders