substantially fewer array-element compares. This is best practice as of
Kntuh Volume 3 Ed 2, and the code is actually simpler this way (although
the key idea may be counter-intuitive at first glance! breaking out of
a loop early loses when it costs more to try to get out early than getting
out early saves).
Also added a comment block explaining the difference and giving some real
counts; demonstrating that heapify() is more efficient than repeated
heappush(); and emphasizing the obvious point thatlist.sort() is more
efficient if what you really want to do is sort.
Added new heapify() function, which transforms an arbitrary list into a
heap in linear time; that's a fundamental tool for using heaps in real
life <wink>.
Added heapyify() test. Added a "less naive" N-best algorithm to the test
suite, and noted that this could actually go much faster (building on
heapify()) if we had max-heaps instead of min-heaps (the iterative method
is appropriate when all the data isn't known in advance, but when it is
known in advance the tradeoffs get murkier).
at random, and replaces the elements at those positions with new random
values. I was pleasantly surprised by how fast this goes! It's hard to
conceive of an algorithm that could special-case for this effectively.
Plus it's exactly what happens if a burst of gamma rays corrupts your
sorted database on disk <wink>.
i 2**i *sort ... %sort
15 32768 0.18 ... 0.03
16 65536 0.24 ... 0.04
17 131072 0.53 ... 0.08
18 262144 1.17 ... 0.16
19 524288 2.56 ... 0.35
20 1048576 5.54 ... 0.77
and age of rampant computer breakins I imagine there are plenty of systems
with telnet disabled. Successful check of at least one getservbyname() call
is required for success
in the stability tests.
Bizarre: this takes 11x longer to run if and only if test_longexp is
run before it, on my box. The bigger REPS is in test_longexp, the
slower this gets. What happens on your box? It's not gc on my box
(which is good, because gc isn't a plausible candidate here).
The slowdown is massive in the parts of test_sort that implicitly
invoke a new-style class's __lt__ or __cmp__ methods. If I boost
REPS large enough in test_longexp, even the test_sort tests on an array
of size 64 visibly c-r-a-w-l. The relative slowdown is even worse in
a debug build. And if I reduce REPS in test_longexp, the slowdown in
test_sort goes away.
test_longexp does do horrid things to Win98's management of user
address space, but I thought I had made that a whole lot better a month
or so ago (by overallocating aggressively in the parser).
If the long is large enough, the return value will be a negative int.
In this case, calling the function a second time won't return the
original value passed in.
imports of test modules now import from the test package. Other
related oddities are also fixed (like DeprecationWarning filters that
weren't specifying the full import part, etc.). Also did a general
code cleanup to remove all "from test.test_support import *"'s. Other
from...import *'s weren't changed.
See there for a description.
Added test case.
Bugfix candidate for 2.2.x, not sure about previous versions:
probably low priority, because virtually no one runs debug builds.
to executing Run/F5 from an EditorWindow.
M ScriptBinding.py : add call to clear_the_environment()
M run.py : implemented Executive.clear_the_environment()
Martin v. Löwis
Tim Peters
Andrew MacIntyre
Piers Lauder
Guido van Rossum
Skip Montanaro
Jeremy Hylton
Barry Warsaw
Thomas Heller
Michael W. Hudson
Neal Norwitz
Kurt B. Kaiser
Jack Jansen