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Ensure that "true" and "false" won't go in same bucket in hash table
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Previously, "hash true" and "hash false" were both congruent to 1 (mod
4).  We just set them to 1 and 0, resp.

Also update the corresponding basic test.
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d-torrance committed Sep 12, 2024
1 parent 9d1e0c2 commit 45df73f
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Showing 2 changed files with 3 additions and 5 deletions.
2 changes: 1 addition & 1 deletion M2/Macaulay2/d/basic.d
Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@ export hash(e:Expr):hash_t := (
is s:SymbolBody do s.symbol.hash
is x:Database do x.hash
is x:ZZcell do hash(x.v)
is b:Boolean do if b.v then hash_t(444777) else hash_t(777333)
is b:Boolean do Ccode(hash_t, b.v)
is Nothing do hash_t(333889)
is x:List do x.hash
is f:functionCode do f.hash
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6 changes: 2 additions & 4 deletions M2/Macaulay2/m2/basictests/hashcodes.m2
Original file line number Diff line number Diff line change
Expand Up @@ -11,15 +11,13 @@ assert( (hash (1,2,3)) === 568179786079386623 )
assert( (hash [1,2,3]) === 9684772971066268688 )
assert( (hash (3/5)) === 6499208 )
assert( (hash new HashTable from { 1 => 2 , 3 => 4 }) === 14342786426447859 )
assert( (hash true) === 444777 )
assert( (hash false) === 777333 )
assert( (hash true) === 1 )
assert( (hash false) === 0 )
assert( (hash null) === 333889 )
assert( (hash Nothing) === 1000069 )
assert( (hash (1 => 2)) === 1729140528276943882 )
assert( hash Nothing == 1000069 )
assert( (hash Boolean) === 1000035 )
assert( (hash true) === 444777 )
assert( (hash false) === 777333 )

-- these might change if our floating point implementation changes, but let's check anyway:
assert( hash 1.23p200 === 18446744072207201388 -* 64-bit *- or hash 1.23p200 == 18446744073069319069 -* 32-bit *- )
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