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KeyBuilder: change int to direct str representation #261

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matthiasdiener
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@matthiasdiener matthiasdiener commented Sep 3, 2024

Followup of #260.

Comment on lines +438 to +440
assert keyb(1) == keyb("1")
assert keyb(1.0) != keyb("1.0") # '1.0' uses hex representation
assert keyb(1+1j) == keyb("(1+1j)")
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@matthiasdiener matthiasdiener Sep 3, 2024

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Not sure if this is an issue. If it is, we could change the KeyBuilder to (int, str(key)).

@@ -432,9 +432,13 @@ def test_scalar_hashing() -> None:
assert keyb(np.int32(1)) == keyb(np.int32(1))
assert keyb(np.int32(2)) != keyb(np.int32(1))
assert keyb(np.int64(1)) == keyb(np.int64(1))
assert keyb(1) == keyb(np.int64(1))
assert keyb(1) != keyb(np.int64(1))
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Wait, I thought the goal was to keep them the same?

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From your answer to my question in #260, my interpretation was that they don't need to be the same. Changing the code like in this PR perhaps also addresses #262.

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They need to be the same. The fundamental property of a hash function $h$ is that $x = y \Rightarrow h(x) = h(y)$. Since

>>> np.int32(1) == 1
True

our hands are tied. I'm sorry if my early comment was ambiguous.

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@matthiasdiener matthiasdiener Jan 16, 2025

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Hmm, we already break this principle in some (many?) places:

>>> from pytools.persistent_dict import KeyBuilder
>>> keyb = KeyBuilder()
>>> 1.0 == 1
True
>>> keyb(1.0) == keyb(1)
False

(with current main branch)

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mgorny commented Nov 22, 2024

Just FYI, the tests pass on PPC64 BE with this patch applied.

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inducer commented Jan 16, 2025

Unsubscribing... @-mention or request review once it's ready for a look or needs attention.

@inducer inducer closed this in #285 Jan 17, 2025
@matthiasdiener matthiasdiener deleted the keyb-int-str branch January 17, 2025 20:02
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3 participants