Scientific computing in Ruby can be improved using JRuby to leverage Java libraries and GPU processing. NMatrix, a numerical matrix library, was optimized for JRuby by reimplementing it to use efficient Java functions, improving speed by 1000x and reducing memory usage by 10x. Further optimizations for NMatrix-JRuby and integrating a general purpose GPU library called ArrayFire could enable faster matrix operations and transparent GPU processing for scientific applications in Ruby.