pgsql: Avoid use of float arithmetic in bipartite_match.c. - Mailing list pgsql-committers

From Tom Lane
Subject pgsql: Avoid use of float arithmetic in bipartite_match.c.
Date
Msg-id E1ZTYfD-0005B0-4M@gemulon.postgresql.org
Whole thread Raw
Responses Re: pgsql: Avoid use of float arithmetic in bipartite_match.c.  (Andres Freund <andres@anarazel.de>)
List pgsql-committers
Avoid use of float arithmetic in bipartite_match.c.

Since the distances used in this algorithm are small integers (not more
than the size of the U set, in fact), there is no good reason to use float
arithmetic for them.  Use short ints instead: they're smaller, faster, and
require no special portability assumptions.

Per testing by Greg Stark, which disclosed that the code got into an
infinite loop on VAX for lack of IEEE-style float infinities.  We don't
really care all that much whether Postgres can run on a VAX anymore,
but there seems sufficient reason to change this code anyway.

In passing, make a few other small adjustments to make the code match
usual Postgres coding style a bit better.

Branch
------
REL9_5_STABLE

Details
-------
http://git.postgresql.org/pg/commitdiff/4022f94c350f96fc5feff0503d3e2f2f6f9086cc

Modified Files
--------------
src/backend/lib/bipartite_match.c |   75 +++++++++++++++++++++++--------------
src/include/lib/bipartite_match.h |   16 ++++----
2 files changed, 55 insertions(+), 36 deletions(-)


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