Class: Glaemscribe::API::SheafChainIterator

Inherits:
Object
  • Object
show all
Defined in:
lib/api/sheaf_chain_iterator.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(sheaf_chain, cross_schema = nil) ⇒ SheafChainIterator

If a cross schema is passed, the prototype of the chain will be permutated



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# File 'lib/api/sheaf_chain_iterator.rb', line 32

def initialize(sheaf_chain, cross_schema = nil)
  @sheaf_chain            = sheaf_chain
  # Sizes contains the number of fragments/sheaf
  @sizes                  = sheaf_chain.sheaves.map { |sheaf| sheaf.fragments.count }
  # An array of counters, one for each sheaf, to increment on fragments
  @iterators              = Array.new(@sizes.count,0)
    
  @errors                 = []
    
  # Construct the identity array
  identity_cross_array    = []
  sheaf_count             = sheaf_chain.sheaves.count
  sheaf_count.times{|i| identity_cross_array << i+1}  

  # Construct the cross array
  if cross_schema
    @cross_array          = cross_schema.split(",").map{ |i| i.to_i }
    ca_count              = @cross_array.count
    @errors << "#{sheaf_count} sheafs found in right predicate, but #{ca_count} elements in cross rule."  if ca_count != sheaf_count  
    @errors << "Cross rule should contain each element of #{identity_cross_array} once and only once."    if identity_cross_array != @cross_array.sort
  else
    @cross_array = identity_cross_array
  end    
end

Instance Attribute Details

#cross_map ⇒ Object

Returns the value of attribute cross_map.



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# File 'lib/api/sheaf_chain_iterator.rb', line 28

def cross_map
  @cross_map
end

#errors ⇒ Object

Returns the value of attribute errors.



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# File 'lib/api/sheaf_chain_iterator.rb', line 29

def errors
  @errors
end

#sheaf_chain ⇒ Object

Returns the value of attribute sheaf_chain.



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# File 'lib/api/sheaf_chain_iterator.rb', line 27

def sheaf_chain
  @sheaf_chain
end

Instance Method Details

#combinations ⇒ Object

Calculate all cominations for the chain



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# File 'lib/api/sheaf_chain_iterator.rb', line 91

def combinations
  resolved = []
  @iterators.each_with_index{ |counter, index|
    sheaf     = sheaf_chain.sheaves[index]
    fragment  = sheaf.fragments[counter]
    
    resolved << fragment.combinations
  }
  res = resolved[0]
  (resolved.count-1).times { |i|
    res = res.product(resolved[i+1]).map{|e1,e2| e1+e2} 
  }
  res
end

#iterate ⇒ Object 



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# File 'lib/api/sheaf_chain_iterator.rb', line 74

def iterate
  pos = 0
  while pos < @sizes.count do
    realpos = @cross_array[pos]-1
    @iterators[realpos] += 1
    if @iterators[realpos] >= @sizes[realpos]
      @iterators[realpos] = 0
      pos += 1
    else
      return true
    end
  end
  # Wrapped!
  return false
end

#prototype ⇒ Object

Calculate the prototype of the chain



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# File 'lib/api/sheaf_chain_iterator.rb', line 58

def prototype
  res   = @sizes.clone
  res2  = @sizes.clone 
  
  res.count.times{ |i| res2[i] = res[@cross_array[i]-1] }
  res   = res2
    
  # Remove all sheaves of size 1 (which are constant)
  res.delete(1)
  
  # Create a prototype string
  res = res.join("x")
  res = "1" if res.empty?
  res
end