Re: [Boost-users] extraction invariants from intensive-loop based on template parameters

Subject: Re: [Boost-users] extraction invariants from intensive-loop based on template parameters
From: Matthieu Brucher (matthieu.brucher_at_[hidden])
Date: 2009-02-19 08:17:20

Hi,

The compiler is smart enough to prune an if condition if it knows that
the value is always false.
So if you add an if(!Lower::IsConstant) before and after your loop,
you don't have to rewrite it.

Matthieu

2009/2/19 Hicham Mouline <hicham_at_[hidden]>:
> Hello,
>
> I have an algorithm like:
>
> template <typename Upper, typename Lower>
> class X {
>
> static void f()
> {
> ....
> for (size_t n=0; n<=N; ++n)
> {
>  // process for j=0 at every n if Lower::IsConstant is false
>  for (size_t j=1; j<=J-1; ++j)
>  {
>  }
>  // process for j=J at every n if Upper::IsConstant is false
> }
> ....
> }
>
>
> So I extracted the double for loop in a separate wrapper class and
> I verbosely wrote 4 specializations with template args begin bool :
>
> <true, true>
> <false, true>
> <true, false>
> <false, false>
>
> for e.g. for <true, true>
>
> // process for j=0 once
> for (size_t n=0; n<=N; ++n)
> {
>  for (size_t j=1; j<=J-1; ++j)
>  {
>  }
> }
> // process for j=J once
>
>
> Any advice?
> Is there a better way than writing explicitly the tmpl specializations? Boost.PP maybe?
>
> rds,
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> Boost-users_at_[hidden]
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>

-- 
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