[Python-Dev] Guarantee ordered dict literals in v3.7? (original) (raw)

Chris Angelico rosuav at gmail.com
Mon Nov 6 05:48:37 EST 2017

On Mon, Nov 6, 2017 at 9:36 PM, Stefan Krah <stefan at bytereef.org> wrote:

On Mon, Nov 06, 2017 at 12🔞17PM +0200, Paul Sokolovsky wrote:

MicroPython hashmap implementation is effectively O(n) (average and worst case) due to the algorithm parameters chosen (like the load factor of 1). Of course, parameters could be tweaked, but the ones chosen are so because the memory usage is far more important for MicroPython systems than performance characteristics (all due to small amounts of memory). Like, MicroPython was twice as fast than Python 3.3 on average, and 1000 times more efficient in the memory usage. $ cat xxx.py def pifloat(): """native float""" lasts, t, s, n, na, d, da = 0, 3.0, 3, 1, 0, 0, 24 while s != lasts: lasts = s n, na = n+na, na+8 d, da = d+da, da+32 t = (t * n) / d s += t return s for i in range(100000): x = pifloat() $ time ./micropython xxx.py real 0m4.424s user 0m4.406s sys 0m0.016s $ $ time ../../cpython/python xxx.py real 0m1.066s user 0m1.056s sys 0m0.010s

Congratulations ...

Maybe I'm misreading your demo, but I fail to see what this has to do with dict performance?

ChrisA

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