Ractor for true parallelism in Ruby - Mini Project: Build & Apply

Using Ractor for True Parallelism in Ruby

📖 Scenario: You want to speed up a task by running parts of it at the same time using Ruby's Ractor feature. This helps use multiple CPU cores to do work faster.

🎯 Goal: Build a Ruby program that uses Ractor to run two tasks in parallel and then combines their results.

📋 What You'll Learn

Create two Ractors that each calculate a sum of numbers

Use a variable to hold the range limit for the sums

Collect results from both Ractors

Print the combined total sum

💡 Why This Matters

🌍 Real World

Using Ractors helps programs run faster by doing multiple things at once, like processing big data or handling many users.

💼 Career

Understanding Ractors is useful for Ruby developers working on performance-critical applications or server-side programs that need true parallelism.

1

Create a variable with the range limit

Create a variable called limit and set it to 1000000.

Ruby

# Create a variable called limit and set it to 1000000
# Your code here

Need a hint?

Use = to assign the number 1000000 to the variable limit.

2

Create two Ractors to calculate sums in parallel

Create two Ractors named r1 and r2. Each should calculate the sum of numbers from 1 to limit divided by 2. Use Ractor.new and a block that sums the range.

Ruby

limit = 1000000
# Create two Ractors r1 and r2 to sum numbers from 1 to limit/2
# Your code here

Need a hint?

Use Ractor.new(limit) { |n| ... } to create each Ractor. Use sum on the range inside the block.

3

Receive results from both Ractors

Create two variables result1 and result2. Assign them the values received from r1.take and r2.take respectively.

Ruby

limit = 1000000
r1 = Ractor.new(limit) { |n| (1..(n/2)).sum }
r2 = Ractor.new(limit) { |n| ((n/2 + 1)..n).sum }
# Receive results from r1 and r2
# Your code here

Need a hint?

Use r1.take and r2.take to get the results from each Ractor.

4

Print the combined total sum

Print the sum of result1 and result2 using puts.

Ruby

limit = 1000000
r1 = Ractor.new(limit) { |n| (1..(n/2)).sum }
r2 = Ractor.new(limit) { |n| ((n/2 + 1)..n).sum }
result1 = r1.take
result2 = r2.take
# Print the combined total sum
# Your code here

Need a hint?

Use puts result1 + result2 to show the total sum.