Removing two solutions from the leaderboard temporarily, as they violated the "must work with all station names" rule and are prone to hash collisions for names not in the current data set. Will bring them back once these submissions have been updated.
Added SWAR (SIMD Within A Register) code to increase bytebuffer processing/throughput
Delaying the creation of the String by comparing hash, segmenting like spullara, improved EOL finding
Co-authored-by: Gunnar Morling <gunnar.morling@googlemail.com>
* Initial implementation using Shenandoah GC and parallel iteration
* Use memory mapped files
* Iterate the buffer once and use BigDecimal parsing instead of Double.parseDouble
* Add information about Graal
* Add sdk use to calculate script
* Memory mapped file, single-pass parsing, custom hash map, fixed thread pool
The threading was a hasty addition and needs work
* Used arraylist instead of treemap to reduce a little overhead
We only need it sorted for output, so only construct a treemap for output
* Attempt to speed up double conversion
* Cap core count for low-core systems
* Fix wrong exponent
* Accumulate measurement value in double, seems marginally faster
Benchmark Mode Cnt Score Error Units
DoubleParsingBenchmark.ourToDouble thrpt 10 569.771 ± 7.065 ops/us
DoubleParsingBenchmark.ourToDoubleAccumulateInToDouble thrpt 10 648.026 ± 7.741 ops/us
DoubleParsingBenchmark.ourToDoubleDivideInsteadOfMultiply thrpt 10 570.412 ± 9.329 ops/us
DoubleParsingBenchmark.ourToDoubleNegative thrpt 10 512.618 ± 8.580 ops/us
DoubleParsingBenchmark.ourToDoubleNegativeAccumulateInToDouble thrpt 10 565.043 ± 18.137 ops/us
DoubleParsingBenchmark.ourToDoubleNegativeDivideInsteadOfMultiply thrpt 10 511.228 ± 13.967 ops/us
DoubleParsingBenchmark.stringToDouble thrpt 10 52.310 ± 1.351 ops/us
DoubleParsingBenchmark.stringToDoubleNegative thrpt 10 50.785 ± 1.252 ops/us
It is useful to debug differences between implementations, e.g.:
```sh
$ while ./create_measurements.sh 1000 && diff <(./calculate_average_royvanrijn.sh 2>/dev/null | ./tocsv.sh) <(./calculate_average.sh 2>/dev/null | ./tocsv.sh) ; do echo OK; done
Created file with 1,000 measurements in 50 ms
60c60
< Bucharest;-2.9;2.9;6.1
---
> Bucharest;-2.9;2.8;6.1
265c265
< Petropavlovsk-Kamchatsky;0.9;9.3;17.7
---
> Petropavlovsk-Kamchatsky;0.9;9.2;17.7
```
For #14
