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How to use config method of Knapsack Package

Best Knapsack_ruby code snippet using Knapsack.config

branch_and_bound.rb

Source:branch_and_bound.rb

...6    #7    # @param instance [Instance] 0/1 knapsack problem instance8    def initialize(instance)9      @instance = instance10      @config = Array.new(instance.things.size)11    end12    # Solve the instance of 0/1 knapsack problem.13    #14    # @return [Hash] resulting price and thing configuration (0 = thing is not in the knapsack, 1 = thing is there)15    def run16      solve(0)17      { price: @best_price, config: @best_config }18    end19    protected20    # Solve the problem starting at specified thing.21    #22    # @param index [Integer] index of thing which will be decided (put in or out from the knapsack) the next23    def solve(index)24      @config[index] = 025      solve(index + 1) unless stop(index)26      @config[index] = 127      solve(index + 1) unless stop(index)28    end29    # Determine if solving of current branch should continue.30    #31    # @param index [Integer] index of the last decided thing so far32    # @return [true, false] weather to continue with solving current branch.33    def stop(index)34      # Update of the best price so far35      weight = config_weight(0, index)36      price = config_price(0, index)37      update_best_price(price, weight, index)38      # No more things to put into the knapsack39      return true if index >= (@instance.things.size - 1)40      # The knapsack is overloaded, do not continue this branch41      return true if weight > @instance.weight_capacity42      if instance_variable_defined?('@best_price') &&43         ((price + get_price_of_remaining_things(index + 1)) <= @best_price)44        # Adding all the ramining things does not produce better price45        return true46      end47      false48    end49    # Update the best price achieved so far.50    #51    # @param price [Integer] price of the current configuration52    # @param weight [Integer] weight of the current configuration53    # @param index [Integer] index of the next thing presence of which will be decided54    def update_best_price(price, weight, index)55      if !instance_variable_defined?('@best_price') ||56         ((weight <= @instance.weight_capacity) && (price > @best_price))57        @best_price = price58        valid_len = index + 159        remaining = @config.size - index - 160        # All undecided things will not be put into the knapsack61        @best_config = @config.slice(0, valid_len).fill(0, valid_len, remaining)62        @best_config_index = index63      end64    end65    # Gets weight of set of things. The set is subset of the things ordered by66    # their index.67    #68    # @param start_index [Integer] index of the first thing included in the set69    # @param end_index [Integer] index of the last thing included in the set70    # @return [Integer] weight of the things71    def config_weight(start_index, end_index)72      weight = 073      @config[start_index..end_index].each_with_index do |presence, index|74        weight += presence * @instance.things[index].weight75      end76      weight77    end78    # Gets price of set of things. The set is subset of the things ordered by79    # their index.80    #81    # @param start_index [Integer] index of the first thing included in the set82    # @param end_index [Integer] index of the last thing included in the set83    # @return [Integer] price of the things84    def config_price(start_index, end_index)85      price = 086      @config[start_index..end_index].each_with_index do |presence, index|87        price += presence * @instance.things[index].price88      end89      price90    end91    # Gets sum of prices of things for which their presence in the knapsack92    # was not decided yet.93    #94    # @param from_index [Integer] index of the first undecided thing95    # @return [Integer] price of the remaining things96    def get_price_of_remaining_things(from_index)97      price = 098      to_index = @instance.things.size - 199      @instance.things[from_index..to_index].each { |t| price += t.price }100      price...

heuristic_price_weight.rb

Source:heuristic_price_weight.rb

...8    #9    # @param instance [Instance] 0/1 knapsack problem instance10    def initialize(instance)11      @instance = instance12      @config = Array.new(instance.things.size) { 0 }13      @sorted_things = instance.things.sort do |a, b|14        (b.price.to_f / b.weight) <=> (a.price.to_f / a.weight)15      end16    end17    # Solve the instance of 0/1 knapsack problem.18    #19    # @return [Hash] resulting price and thing configuration (0 = thing is not in the knapsack, 1 = thing is there)20    def run21      solve22      { price: @best_price, config: @best_config }23    end24    protected25    # Solve the instance of 0/1 knapsack problem.26    def solve27      @sorted_things.each do |thing|28        break if (config_weight + thing.weight) > @instance.weight_capacity29        @config[thing.index] = 130      end31      @best_price = config_price32      @best_config = @config.dup33    end34    # Gets total weight of things present in the knapsack.35    #36    # @return [Integer] total weight37    def config_weight38      @config.each_with_index.reduce(0) do |weight, (presence, index)|39        weight + presence * @instance.things[index].weight40      end41    end42    # Gets total price of things present in the knapsack.43    #44    # @return [Integer] total price45    def config_price46      @config.each_with_index.reduce(0) do |price, (presence, index)|47        price + presence * @instance.things[index].price48      end49    end50  end51end...

timing_adapter.rb

Source:timing_adapter.rb

1require 'knapsack'2# Generates more accurate reports for knapsack by timing :all blocks3class TimingAdapter < Knapsack::Adapters::RspecAdapter4  def bind_time_tracker5    ::RSpec.configure do |config|6      config.before(:all) do7        Knapsack.tracker.test_path = self.class.metadata[:example_group][:file_path]8        Knapsack.tracker.start_timer9      end10      config.after(:all) do11        Knapsack.tracker.stop_timer12      end13      config.after(:suite) do14        Knapsack.logger.info(Knapsack::Presenter.global_time)15      end16    end17  end18end19TimingAdapter.bind...

config

Using AI Code Generation

1 { weight: 1, value: 2 },2 { weight: 3, value: 3 },3 { weight: 2, value: 4 },4 { weight: 4, value: 5 }

config

Using AI Code Generation

1knapsack.config(100, 10)2 def config(capacity, weight)3knapsack.config(100, 10)

config

Using AI Code Generation

1 { weight: 1, value: 2 },2 { weight: 3, value: 3 },3 { weight: 2, value: 4 },4 { weight: 4, value: 5 }

config

Using AI Code Generation

1knapsack.config(100, 10)2 def config(capacity, weight)3knapsack.config(100, 10)

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