Let's say I have grammar etc.. for writing algebra code like : a = b+c, u = x + y, z = 3*e; and have each sub expression containing a = call to be evaluated on a different processor. Where can I put the evaluation call using the context ? In the destructor of my associated expression ?
Joel Falcou wrote:
Let's say I have grammar etc.. for writing algebra code like : a = b+c, u = x + y, z = 3*e; and have each sub expression containing a = call to be evaluated on a different processor.
Where can I put the evaluation call using the context ? In the destructor of my associated expression ?
Interesting. You might try disabling Proto's comma operator and writing your own that fires off expression evaluations. -- Eric Niebler BoostPro Computing http://www.boostpro.com
Eric Niebler a écrit :
Interesting. You might try disabling Proto's comma operator and writing your own that fires off expression evaluations.
I thought of that but I need the whole AST for checking for various stuff. Basically I transform a algebra AST into a a pair of objects : a tuples of matrix begin() pointer and a stripped AST so I can generate a software pipelined evaluation loop nest. I tried adding the destructor-based evaluation and it seems to work but I fear there may be some side-effects I'll regret later.
Joel Falcou wrote:
Eric Niebler a écrit :
Interesting. You might try disabling Proto's comma operator and writing your own that fires off expression evaluations.
I thought of that but I need the whole AST for checking for various stuff. Basically I transform a algebra AST into a a pair of objects : a tuples of matrix begin() pointer and a stripped AST so I can generate a software pipelined evaluation loop nest.
I tried adding the destructor-based evaluation and it seems to work but I fear there may be some side-effects I'll regret later.
Aside from the usual advice against doing stuff in destructors that can fail ... how do you ensure that only the top-level (outermost) object's destructor causes an evaluation? Might it be cleaner to be more explicit about evaluation, e.g., like: eval(( a = b+c, u = x + y, z = 3*e )); ? -- Eric Niebler BoostPro Computing http://www.boostpro.com
Eric Niebler a écrit :
Aside from the usual advice against doing stuff in destructors that can fail ... how do you ensure that only the top-level (outermost) object's destructor causes an evaluation?
I actually have a flag in the expression that is set when the expression is used as a rhs in operator=. Side effect of doing this is that I can optimize a =b =c+d into a single nest loop instead of one nest loop + memcpying the data. In which cases a destructor can fail ?
Might it be cleaner to be more explicit about evaluation, e.g., like:
eval(( a = b+c, u = x + y, z = 3*e )); It may but it'll break existing code and looks far less intuitive.
___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35
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