feldtruby

Robert Feldt's Common Ruby Code lib. I will gradually collect the many generally useful Ruby tidbits I have laying around and clean them up into here. Don't want to rewrite these things again and again... So far this collects a number of generally useful additions to the standard Ruby classes/libs and then includes a simple optimization framework (FeldtRuby::Optimize).

Note that good documentation is not really a focus here. As things mature in here I will move logically unique/separate sets of functionality into separate Ruby libs/gems of useful code. At that point there will be more focus on documentation.

email: robert.feldt ((a)) gmail.com

• Cluster linkage metrics
• Access to R from Ruby (extends existing lib so that you can more easily transfer complex objects back to Ruby)
• ...

Time.timestamp()    				# Get a timestamp string back with the current time

Basic calc/statistics: sum, mean, average, stdev, variance, rms, weighted_sum, weighted_mean, sum_of_abs, sum_of_abs_deviations

[1,2,3].swap!(0,2) 					=> [3, 2, 1] # destructive swap of two elements
[1,2,5].distance_between_elements 	=> [1, 3]
[15, 1, 7, 0].ranks					=> [1, 3, 2, 0]
[[2.3, :a], [1.7, :b]].ranks_by {|v| v[0]}	=> [[1, 2.3, :a], [2, 1.7, :b]]

1.456.round_to_decimals(2) 			=> 1.46 (round to given num of decimals)

Watch for file changes in given paths then call hooks with the updated files.

rand_int(top)	 					# random integer in range 0...top

A simple optimization framework with classes:

• Objective (single or multi-objective optimization critera)
• SearchSpace (capture constraints for optimization values/parameters)
• RandomSearcher (random search for optimal values)
• DifferentialEvolution (effective numerical optimization with evolutionary algorithm)

but also support for different type of logging etc. Setting up an optimization can be quite involved but there is a simple wrapper method, with good defaults, for numerical optimization using DE:

# Optimizing with the Rosenbrock function on [0, 2], see:
# 	http://en.wikipedia.org/wiki/Rosenbrock_function
require 'feldtruby/optimize'
xbest, ybest = FeldtRuby::Optimize.optimize(0, 2) {|x, y|
	(1 - x)**2 + 100*(y - x*x)**2
}

Copyright (c) 2012-2013 Robert Feldt. See LICENSE.txt for further details.