It was 2022. I was at the end of my third year at Jagannath University. I remember I took a course named Operations Management. At that time, my course instructor was Prof. Dr. Moniruzzaman. During my course, I learned lots of things related to operations management. I remember designing plant layouts being interesting at that time because they required critical thinking and design efficiency!

I was learning Ruby then because I heard Metasploit was being transferred from Python to Ruby. That's why I started exploring Ruby. I also like Ruby on Rails because of its features. That is also a big reason to choose Ruby over Python. So, I started planning to build a simple meta program using Ruby to solve this plant layout. There can be many results of plant layout design but the lowest one is the most efficient. 

At first, I took a CSV file that contained the existing plant layout. 

Aggregate Flow Matrix

I could have put everything in one file but I chose to keep files separate. I made a reader file that reads data from CSV and turns it into a 2D array using Ruby's roo gem. 

Reader File (reader.rb)

So, I had a CSV containing the existing plant layout. I had a reader system. All I needed to do was to manipulate the 2D array and find out the most efficient layout plant.

Here's how I approached the problem.

first_line =  [2, 1, 6, 3]
second_line = [7, 5, 8, 4]

length = first_line.length
actual_length = length * 2
total = 0

for i in 1..actual_length-1
  if first_line.include? i
    main = first_line.index(i)
  else
    main = second_line.index(i)
  end
  main += 1
  for j in i+1..actual_length
    if first_line.include? j
      second_main = first_line.index(j)
    else
      second_main = second_line.index(j)
    end
    second_main += 1

    step = (main - second_main).abs

    if step == 0
      step = 1
    end
    data = $plant.cell(i, j-1)
    puts "#{i} - #{j} -> #{data} x #{step} = #{data * step}"
    total += data * step
  end
  if i+1 != 8
    puts "new line #{i+1}"
  end
end

Here, first_line and second_line represents the initial layout with the value of costing. And this program generates the lowest possible transaction cost of plant layout design. I wrote it in 2022 and forgot about Ruby. However, I have got some plans with Ruby on Rails. I will talk about this here someday.