255810db64
This PR fixes a bug in Float32.ofInt, which previously returned a Float(64). Closes https://github.com/leanprover/lean4/issues/7264
51 lines
1.3 KiB
Text
51 lines
1.3 KiB
Text
/-- info: 2.100000 -/
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#guard_msgs in
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#eval (2.1 : Float32)
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/-- info: 3.200000 -/
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#guard_msgs in
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#eval (2.1 : Float32) + 1.1
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/-- info: 0.900000 -/
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#guard_msgs in
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#eval (2.1 : Float32) - 1.2
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def test1 : IO Unit := do
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IO.println ((2 : Float32).sin);
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IO.println ((2 : Float32).cos);
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IO.println ((2 : Float32).sqrt);
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IO.println ((2 : Float32) ^ (100 : Float32));
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/--
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info: 0.909297
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-0.416147
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1.414214
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1267650600228229401496703205376.000000
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-/
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#guard_msgs in
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#eval test1
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/-- info: 0.909297 -/
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#guard_msgs in
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#eval (2 : Float32).sin.toFloat
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/-- info: 0.909297 -/
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#guard_msgs in
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#eval (2 : Float).sin.toFloat32
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/-- info: 1606938044258990275541962092341162602522202993782792835301376.000000 -/
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#guard_msgs in
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#eval (2 : Float32).toFloat ^ (200 : Float32).toFloat
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#guard (Float32.ofInt (-1 : Int)).toBits == 0xBF800000
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-- 2^24 + 1 is the smallest Nat that can't be represented exactly in FP32 but can in FP64;
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-- There are 23 bits of mantissa and an implicit leading 1. Additionally, powers of
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-- 2 (within range) are exactly representable in either format.
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-- This shows that we are not accidentally representing Float32 with 64 bits;
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#guard
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let n := Int.pow 2 24
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(Float.ofInt n) - (Float32.ofInt n).toFloat == 0
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#guard
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let n := Int.pow 2 24 + 1
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(Float.ofInt n) - (Float32.ofInt n).toFloat != 0
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