Changes between Version 1 and Version 5 of Ticket #17408
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 11/28/14 06:19:59 (6 years ago)
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Ticket #17408

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ce577a909e3ac2835f975cc9515b54459174e8ca
 Property Keywords poset added

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u/ncohen/17408

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Ticket #17408 – Description
v1 v5 3 3 This branch reimplements it for acyclic graphs. 4 4 5 Before6 5 {{{ 7 6 sage: g = posets.BooleanLattice(5).hasse_diagram().transitive_closure(); g = g.cartesian_product(g) 8 sage: %time Poset(g)9 CPU times: user 1.3 s, sys: 8 ms, total: 1.3 s 10 Wall time: 1.29 s 11 Finite poset containing 1024 elements 7 sage: %timeit g.transitive_reduction() 8 1 loops, best of 3: 1.02 s per loop 9 sage: %timeit g.transitive_reduction(acyclic=True) 10 10 loops, best of 3: 28.9 ms per loop 12 11 }}} 13 12 14 After 15 {{{ 16 sage: g = posets.BooleanLattice(5).hasse_diagram().transitive_closure(); g = g.cartesian_product(g) 17 sage: %time Poset(g) 18 CPU times: user 292 ms, sys: 12 ms, total: 304 ms 19 Wall time: 265 ms 20 Finite poset containing 1024 elements 21 }}} 13 Now the critical part in the creation of a `Poset` is triggered by `UniqueRepresentation`. As soon as you create a `Poset` it is being compared with those that already exists... That is actually precomputing the equality relationships between all existing posets even if you never asked for it, and I personally see it as wasted time (especially since I cannot disable it). 22 14 23 N ote that a LOT of time is lost on calls to `__eq__`. If I make no mistake it is because `Posets` are `UniqueRepresentation`. I would personally be very very glad if we could get rid of that.15 Nathann