https://github.com/MarcAzar/BitVector

BitVector Implementation in Nim
https://github.com/MarcAzar/BitVector

Last synced: about 2 months ago
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BitVector Implementation in Nim

• Host: GitHub
• URL: https://github.com/MarcAzar/BitVector
• Owner: MarcAzar
• License: mit
• Created: 2019-03-01T14:56:48.000Z (over 5 years ago)
• Default Branch: master
• Last Pushed: 2022-05-16T08:04:04.000Z (over 2 years ago)
• Last Synced: 2024-05-18T15:32:35.973Z (4 months ago)
• Language: Nim
• Homepage: https://marcazar.github.io/BitVector/
• Size: 141 KB
• Stars: 15
• Watchers: 1
• Forks: 2
• Open Issues: 2
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

• awesome-nim - BitVector - A high-performance Nim implementation of BitVectors. (Data / Data Structures)

README

        
# BitVector

A high performance Nim implementation of BitVector with base (uint64, uint32, uint16, or uint8), and with support for slices and other `seq` supported operations. BitVector format order is little endian, where Least Significant Byte has the lowest address. BitVector is an in-memory bit vector. A Bloom Fliter is also provided to demonstrate BitVector usage along with Murmur Hashing. If looking for a mmap type BitVector consider using nim-bitarray.

## Example Usage                                                        

```

import bitvector

   

  block:

    var ba = newBitVector[uint](64) # Create a BitVector with uint64 base

    echo ba # Prints capacity in bits = 64, and number of elements = 1

    ba[0] = 1 # Assign `true` to bit index `0`

    ba[2] = 1

    ba[7] = 1 # ba[0..7] now is `10000101` == 13

    assert(ba[0..7] == 133, "incorrect result: " & $ba[0..7]) 

    assert(ba[0..4] == 5, "incorrect result: " & $ba[0..4])

    assert(ba[1..4] == 2, "incorrect result: " & $ba[1..4])

 

  var bitvectorA = newBitVector[uint](2e9)

  bitvectorA[0] = 1

  bitvectorA[1] = 1

  bitvectorA[2] = 1

  

  # Test range lookups/inserts

  bitvectorA[65] = 1

  doAssert bitvectorA[65] == 1

  bitvectorA[131] = 1

  bitvectorA[194] = 1

  assert bitvectorA[2..66] == bitvectorA[131..194]

  let sliceValue = bitvectorA[131..194]

  bitvectorA[270..333] = sliceValue

  bitvectorA[400..463] = uint(-9223372036854775807)

  assert bitvectorA[131..194] == bitvectorA[270..333]

  assert bitvectorA[131..194] == bitvectorA[400..463]

```

## Bloom Filter Performance

A Bloom Filter speed test is included in `test_bloom.nim`. A test case of 10M insertions executes in ~3.2 seconds and 10M lookups in ~3.1 seconds for a Bloom filter with a 1 in 1000 target error rate (0.001) and actual error rate of 0.0007. This was performed on asingle thread by passing the -d:release flag to the Nim compiler on a Dell XP3 13 laptop (i7 with 16GB Ram). `k` was computed to its optimal 10 hash functions, while the Bloom filter size was 18.75MB in size.

## Installation

Install Nim for Windows or Unix by following the instructions in , or preferably by installing choosenim

Once ```choosenim``` is installed you can ```nimble install bitvector``` to pull the latest bipbuffer release and all its dependencies

## Documentation

Documentation can be found BitVector and Bloom Filter