cartesian product...
From: deancoo (s2cuts555_at_yahoo.ca)
Date: 02/28/05
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Date: Mon, 28 Feb 2005 11:24:46 GMT
I need to do a Cartesian product, which is inherently expensive. Turns out,
it's too expensive. I've dropped in that portion of my C++ code in hopes
that someone with greater expertise with STL containers and algorithms would
be able to see if there are any significant inefficiencies in what I've
done. Otherwise, I'm going to have to rethink my solution, which I really
would like to avoid. Thanks for any help.
d
// initialize iterators to vectors
bc_it_start = board_combinations.begin();
bc_it_end = board_combinations.end();
hcmb_it_start = tcart_combinations.begin();
hcmb_it_end = tcart_combinations.end();
for (hcmb_it=hcmb_it_start; hcmb_it!=hcmb_it_end; hcmb_it++) {
for (bc_it=bc_it_start; bc_it!=bc_it_end; bc_it++) {
// set iterators to containers within outside containers
cc_it_start = hcmb_it->mycarts.begin();
cc_it_end = hcmb_it->mycarts.end();
brd_it_start = bc_it->mycarts.begin();
brd_it_end = bc_it->mycarts.end();
copy(cc_it_start, cc_it_end,
back_inserter(current_combination.mycarts));
copy(brd_it_start, brd_it_end,
back_inserter(current_combination.mycarts));
cartesian_prod.push_back(current_combination);
current_combination.mycarts.clear();
};
};
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