merykitty's attempt #114
merykitty's attempt #114
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Oh, wow, this looks very promising. 7.379s on the eval env, fastest so far! Summoning the current top of the pack @royvanrijn, @ebarlas, @spullara, for feedback too! |
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It turns out that just prefetching the file manually helps lower the time by 20% on my machine, now it takes around 2 seconds, for comparison the baseline takes around 106 seconds and just reading the whole file without doing anything takes around 0.75 seconds. Thanks. |
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| private static long iterate(PoorManMap aggrMap, MemorySegment data, long offset) { | ||
| var line = ByteVector.fromMemorySegment(BYTE_SPECIES, data, offset, ByteOrder.nativeOrder()); |
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I suppose this would fail if station names are e.g. 100 double-byte characters, right? Not a problem per se, we agreed yesterday on enforcing a 100 bytes limit for station names (rather than 100 UTF-8 characters), I'm just curious.
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No if we cannot find the delimiter which means the key is longer than the segment we fall back to slow path which do so in a more straightforward way,
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Ah yes, got it. Thanks for adding all the comments!
| return offset; | ||
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| private static long iterate(PoorManMap aggrMap, MemorySegment data, long offset) { |
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Could you provide a description of how that iteration loop works? I roughly get it, but it's quite dense code and having a high-level description would be great.
| long designMask = ~(signed & 0xFF); | ||
| long digits = ((word & designMask) << shift) & 0x0F000F0F00L; | ||
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| // Now digits is in the form 0xUU00TTHH00 |
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What is TT, HH, etc? As for the main loop, could you provide an overview of how this thing works?
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UU stands for the value of the units digit, TT is the tens digit and HH is the hundreds digit.
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After trying again without prefetching I am also able to reach 2s, which is weird. Thanks for your reviews, hope I have addressed those. |
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00:07.620, current #1! Very nice, thanks for participating! |
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How does this one fare our with Graal? |
My attempt at this challenge,
test.sh merykittypassed.Please kindly review, thanks very much.