why this code output isn't true
bn, nbn, smn = 1e+15, -1e+15, 1e-15
print(bn + nbn + smn == smn + bn + nbn)
#this print false
please explain it
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`1e+15 + (-1e+15)` is `1e+15` because of the limited precision of floats. – Thierry Lathuille May 06 '20 at 08:50
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I don't think commutativity from floating-point numbers is a reasonable expectation – Morten Jensen May 06 '20 at 08:55
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@ThierryLathuille `1e+15 + (-1e+15)` evaluates to zero. Did you mean something different? – khelwood May 06 '20 at 08:58
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use `print(bn + nbn + smn, smn + bn + nbn)` and you will see different values `1e-15` and `0.0` Problem is that computer can't keep every float value and it keep only approximation and even `0.1 + 0.2 == 0.3` gives `False` – furas May 06 '20 at 09:34
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@khelwood Oh, yes :/ I meant 1e+15 + 1e-15... Thanks! – Thierry Lathuille May 06 '20 at 09:36