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SPERR 0.5 occasionally violates error tolerance #181

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lindstro opened this issue Dec 14, 2022 · 2 comments
Closed

SPERR 0.5 occasionally violates error tolerance #181

lindstro opened this issue Dec 14, 2022 · 2 comments

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@lindstro
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lindstro commented Dec 14, 2022 •
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Describe the bug
In rare cases, SPERR violates the error tolerance set by --pwe.

To Reproduce
Steps to reproduce the behavior:

  1. Download the Nyx dark matter density field from SDRBench.
  2. Compress field with compressor_3d --dims 512 512 512 --pwe 0x1p-44 -o dmd.sperr dark_matter_density.f32.
  3. Decompress field with decompressor_3d -o dmd.bof dmd.sperr.

Expected and actual behavior
All values should differ by no more than 2-44. The observed maximum absolute error is 7.616e-14, which exceeds the error tolerance of 2-44 ≈ 5.684e-14.

Environment (please complete the following information):

  • OS: macOS 11.7.1
  • Compiler: AppleClang 13.0.0.13000029
  • SPERR Version:
SPERR version: 0.5
Based on code Branch: main
Based on code SHA1  : 48880dd-dirty
shaomeng pushed a commit that referenced this issue Dec 15, 2022
header keeps the number of useful bits rather than bytes. Fix issue #181
85342c8
shaomeng added a commit that referenced this issue Dec 15, 2022
@shaomeng
Header keeps bits (#182)
76f3e9f 
* header keeps the number of useful bits rather than bytes. Fix issue #181

* compressor_3d releases compressor resources before doing decompression

* bump version to 0.5.2

Co-authored-by: Samuel Li <Sam@Navada>
@shaomeng
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Hi Peter, I've located this bug, and believe that it's fixed now (tag v0.5.2). Could you verify?
(I borrowed a header definition from my integer-based implementation, and that's a better definition ;) )

@lindstro
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Thanks, Sam. Yes, that fixes this issue for me.

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@shaomeng @lindstro