Fix float arithmetic in BLF reader #1927
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zariiii9003
reviewed
Feb 28, 2025
| factor = 1e-5 if flags == 1 else 1e-9 | ||
| timestamp = timestamp * factor + start_timestamp | ||
| factor = Decimal("1e-5") if flags == 1 else Decimal("1e-9") | ||
| timestamp = float(Decimal(timestamp) * factor) + start_timestamp |
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I think that can be achieved without Decimal:
factor = 100_000 if flags == 1 else 1_000_000_000
timestamp = (timestamp + round(start_timestamp * factor)) / factorThere was a problem hiding this comment.
I agree that we can achieve it without Decimal.
But what is the downside of using Decimal?
IMO, using the Python built-in module Decimal makes it very obvious what we are doing here.
Using the Python decimal module for fast correctly rounded decimal floating-point arithmetic when applying the timestamp factor.
Now that the BLF float arithmetic issue is fixed we no longer need to tweek the `allowed_timestamp_delta` in the BLF unit tests
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felixdivo
approved these changes
Mar 4, 2025
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Using the Python decimal module for fast correctly rounded decimal floating-point arithmetic when applying the timestamp factor.
The BLF unit tests are also updated to reflect this new accuracy in the read timestamps.