Class: Minimap2::Aligner

Inherits:
Object
  • Object
show all
Defined in:
lib/minimap2/aligner.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(fn_idx_in = nil, seq: nil, preset: nil, k: nil, w: nil, min_cnt: nil, min_chain_score: nil, min_dp_score: nil, bw: nil, bw_long: nil, best_n: nil, n_threads: 3, fn_idx_out: nil, max_frag_len: nil, extra_flags: nil, scoring: nil) ⇒ Aligner

Create a new aligner.

Parameters:

  • fn_idx_in (String) (defaults to: nil) —

    index or sequence file name.

  • seq (String) (defaults to: nil) —

    a single sequence to index.

  • preset (String) (defaults to: nil) —

    minimap2 preset.

    • map-pb : PacBio CLR genomic reads

    • map-ont : Oxford Nanopore genomic reads

    • map-hifi : PacBio HiFi/CCS genomic reads (v2.19 or later)

    • asm20 : PacBio HiFi/CCS genomic reads (v2.18 or earlier)

    • sr : short genomic paired-end reads

    • splice : spliced long reads (strand unknown)

    • splice:hq : Final PacBio Iso-seq or traditional cDNA

    • asm5 : intra-species asm-to-asm alignment

    • ava-pb : PacBio read overlap

    • ava-ont : Nanopore read overlap

  • k (Integer) (defaults to: nil) —

    k-mer length, no larger than 28.

  • w (Integer) (defaults to: nil) —

    minimizer window size, no larger than 255.

  • min_cnt (Integer) (defaults to: nil) —

    minimum number of minimizers on a chain.

  • min_chain_score (Integer) (defaults to: nil) —

    minimum chain score.

  • min_dp_score (defaults to: nil)
  • bw (Integer) (defaults to: nil) —

    chaining and alignment band width. (initial chaining and extension)

  • bw_long (Integer) (defaults to: nil) —

    chaining and alignment band width (RMQ-based rechaining and closing gaps)

  • best_n (Integer) (defaults to: nil) —

    max number of alignments to return.

  • n_threads (Integer) (defaults to: 3) —

    number of indexing threads.

  • fn_idx_out (String) (defaults to: nil) —

    name of file to which the index is written. This parameter has no effect if seq is set.

  • max_frag_len (Integer) (defaults to: nil)
  • extra_flags (Integer) (defaults to: nil) —

    additional flags defined in minimap.h.

  • scoring (Array) (defaults to: nil) —

    scoring system. It is a tuple/list consisting of 4, 6 or 7 positive integers. The first 4 elements specify match scoring, mismatch penalty, gap open and gap extension penalty. The 5th and 6th elements, if present, set long-gap open and long-gap extension penalty. The 7th sets a mismatch penalty involving ambiguous bases.

Raises:

  • (ArgumentError) 


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# File 'lib/minimap2/aligner.rb', line 41

def initialize(
  fn_idx_in = nil,
  seq: nil,
  preset: nil,
  k: nil,
  w: nil,
  min_cnt: nil,
  min_chain_score: nil,
  min_dp_score: nil,
  bw: nil,
  bw_long: nil,
  best_n: nil,
  n_threads: 3,
  fn_idx_out: nil,
  max_frag_len: nil,
  extra_flags: nil,
  scoring: nil
)

  @idx_opt = FFI::IdxOpt.new
  @map_opt = FFI::MapOpt.new

  r = FFI.mm_set_opt(preset, idx_opt, map_opt)
  raise ArgumentError, "Unknown preset name: #{preset}" if r == -1

  # always perform alignment
  map_opt[:flag] |= 4
  idx_opt[:batch_size] = 0x7fffffffffffffff

  # override preset options
  idx_opt[:k] = k if k
  idx_opt[:w] = w if w
  map_opt[:min_cnt] = min_cnt if min_cnt
  map_opt[:min_chain_score] = min_chain_score if min_chain_score
  map_opt[:min_dp_max] = min_dp_score if min_dp_score
  map_opt[:bw] = bw if bw
  map_opt[:bw_long] = bw_long if bw_long
  map_opt[:best_n] = best_n if best_n
  map_opt[:max_frag_len] = max_frag_len if max_frag_len
  map_opt[:flag] |= extra_flags if extra_flags
  if scoring && scoring.size >= 4
    map_opt[:a] = scoring[0]
    map_opt[:b] = scoring[1]
    map_opt[:q] = scoring[2]
    map_opt[:e] = scoring[3]
    map_opt[:q2] = map_opt[:q]
    map_opt[:e2] = map_opt[:e]
    if scoring.size >= 6
      map_opt[:q2] = scoring[4]
      map_opt[:e2] = scoring[5]
      map_opt[:sc_ambi] = scoring[6] if scoring.size >= 7
    end
  end

  if fn_idx_in
    warn "Since fn_idx_in is specified, the seq argument will be ignored." if seq
    reader = FFI.mm_idx_reader_open(fn_idx_in, idx_opt, fn_idx_out)

    # The Ruby version raises an error here
    raise "Cannot open : #{fn_idx_in}" if reader.null?

    @index = FFI.mm_idx_reader_read(reader, n_threads)
    FFI.mm_idx_reader_close(reader)
    FFI.mm_mapopt_update(map_opt, index)
    FFI.mm_idx_index_name(index)
  elsif seq
    @index = FFI.mappy_idx_seq(
      idx_opt[:w], idx_opt[:k], idx_opt[:flag] & 1,
      idx_opt[:bucket_bits], seq, seq.size
    )
    FFI.mm_mapopt_update(map_opt, index)
    map_opt[:mid_occ] = 1000 # don't filter high-occ seeds
  end
end

Instance Attribute Details

#idx_opt ⇒ Object (readonly)

Returns the value of attribute idx_opt.



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# File 'lib/minimap2/aligner.rb', line 5

def idx_opt
  @idx_opt
end

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/minimap2/aligner.rb', line 5

def index
  @index
end

#map_opt ⇒ Object (readonly)

Returns the value of attribute map_opt.



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# File 'lib/minimap2/aligner.rb', line 5

def map_opt
  @map_opt
end

Instance Method Details

#align(seq, seq2 = nil, buf: nil, cs: false, md: false, max_frag_len: nil, extra_flags: nil) ⇒ Array

Note:

Name change: map -> align In the Ruby language, the name map means iterator. The original name is map, but here I use the method name align.

Note:

The use of Enumerator is being considered. The method names may change again.

Returns alignments.

Parameters:

  • seq (String)
  • seq2 (String) (defaults to: nil)
  • buf (FFI::TBuf) (defaults to: nil)
  • cs (true, false) (defaults to: false)
  • md (true, false) (defaults to: false)
  • max_frag_len (Integer) (defaults to: nil)
  • extra_flags (Integer) (defaults to: nil)

Returns:

  • (Array) —

    alignments



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# File 'lib/minimap2/aligner.rb', line 135

def align(
  seq, seq2 = nil,
  buf: nil,
  cs: false,
  md: false,
  max_frag_len: nil,
  extra_flags: nil
)

  return if index.null?
  return if (map_opt[:flag] & 4).zero? && (index[:flag] & 2).zero?

  map_opt[:max_frag_len] = max_frag_len if max_frag_len
  map_opt[:flag] |= extra_flags if extra_flags

  buf ||= FFI::TBuf.new
  km = FFI.mm_tbuf_get_km(buf)

  n_regs_ptr = ::FFI::MemoryPointer.new :int
  regs_ptr = FFI.mm_map_aux(index, seq, seq2, n_regs_ptr, buf, map_opt)
  n_regs = n_regs_ptr.read_int

  regs = Array.new(n_regs) do |i|
    FFI::Reg1.new(regs_ptr + i * FFI::Reg1.size)
  end

  hit = FFI::Hit.new

  cs_str     = ::FFI::MemoryPointer.new(::FFI::MemoryPointer.new(:string))
  m_cs_str   = ::FFI::MemoryPointer.new :int

  alignments = []

  i = 0
  begin
    while i < n_regs
      FFI.mm_reg2hitpy(index, regs[i], hit)

      c = hit[:cigar32].read_array_of_uint32(hit[:n_cigar32])
      cigar = c.map { |x| [x >> 4, x & 0xf] } # 32-bit CIGAR encoding -> Ruby array

      _cs = ""
      if cs
        l_cs_str = FFI.mm_gen_cs(km, cs_str, m_cs_str, @index, regs[i], seq, 1)
        _cs = cs_str.read_pointer.read_string(l_cs_str)
      end

      _md = ""
      if md
        l_cs_str = FFI.mm_gen_md(km, cs_str, m_cs_str, @index, regs[i], seq)
        _md = cs_str.read_pointer.read_string(l_cs_str)
      end

      alignments << Alignment.new(hit, cigar, _cs, _md)

      FFI.mm_free_reg1(regs[i])
      i += 1
    end
  ensure
    while i < n_regs
      FFI.mm_free_reg1(regs[i])
      i += 1
    end
  end
  alignments
end

#free_index ⇒ Object

Explicitly releases the memory of the index object.



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# File 'lib/minimap2/aligner.rb', line 118

def free_index
  FFI.mm_idx_destroy(index) unless index.null?
end

#k ⇒ Object

k-mer length, no larger than 28



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# File 'lib/minimap2/aligner.rb', line 221

def k
  index[:k]
end

#n_seq ⇒ Object 



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# File 'lib/minimap2/aligner.rb', line 231

def n_seq
  index[:n_seq]
end

#seq(name, start = 0, stop = 0x7fffffff) ⇒ Object

Retrieve a subsequence from the index.

Parameters:

  • name
  • start (defaults to: 0)
  • stop (defaults to: 0x7fffffff) 


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# File 'lib/minimap2/aligner.rb', line 207

def seq(name, start = 0, stop = 0x7fffffff)
  return if index.null?
  return if (map_opt[:flag] & 4).zero? && (index[:flag] & 2).zero?

  lp = ::FFI::MemoryPointer.new(:int)
  s = FFI.mappy_fetch_seq(index, name, start, stop, lp)
  l = lp.read_int
  return nil if l == 0

  s.read_string(l)
end

#seq_names ⇒ Object 



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# File 'lib/minimap2/aligner.rb', line 235

def seq_names
  ptr = index[:seq].to_ptr
  Array.new(index[:n_seq]) do |i|
    FFI::IdxSeq.new(ptr + i * FFI::IdxSeq.size)[:name]
  end
end

#w ⇒ Object

minimizer window size, no larger than 255



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# File 'lib/minimap2/aligner.rb', line 227

def w
  index[:w]
end