gysel

require 'bigdecimal'

def integrate (a, b, n)
  a = a.to_f; b = b.to_f; n = n.to_i
  result = 0.0
  
  dx = (b - a) / n
  dx_half = dx / 2
  for i in 0 ... n
    result += yield a + (i * dx)

simplay

# D subset |R Domain over which we integrate - sample D = [1,10]
D = (1..10).to_a

# f:|R->|R function - sample x |-> f(x) := x^2 
f = lambda {|x| x*x}

# summation of function values over our domain
summator = lambda {|function, domain| domain.inject(0){|x,y| x += function.call(y)} }

# Integrations Driver (for real valued 1d functions only) - assumption: integration steps equidistant

Denommus

integral :: (Fractional a, Ord a) => (a -> a) -> Integer -> a -> a -> a
integral f p a b
    | a==b = 0
    | otherwise = total 0 a
    where dx = (b-a)/fromInteger p
          total t x | x2>b      = t
                    | otherwise = total (t+(dx*(f x+(4*f ((x+x2)/2))+f x2)/6)) x2
              where x2 = x+dx

usmanakram232

Wolfie's List

My firends said along with sharing all these tools all the time, maintain a list. So, they don't have to search in old chats. :/ I will populate it slowly with time.

IMPORTANT❗ List is not endorsments. If you use any of these, you are on your own.

Volunteer

• Be My Eyes

ChuckJHardy

class MyJob < ActiveJob::Base
  queue_as :urgent

  rescue_from(NoResultsError) do
    retry_job wait: 5.minutes, queue: :default
  end

  def perform(*args)
    MyService.call(*args)
  end

wvengen

Finding a Ruby memory leak using a time analysis

When developing a program in Ruby, you may sometimes encounter a memory leak. For a while now, Ruby has a facility to gather information about what objects are laying around: ObjectSpace.

There are several approaches one can take to debug a leak. This discusses a time-based approach, where a full memory dump is generated every, say, 5 minutes, during a time that the memory leak is showing up. Afterwards, one can look at all the objects, and find out which ones are staying around, causing the

badboy

#!/usr/bin/env ruby
# encoding: utf-8

require 'memory_profiler'

gem 'redis', ENV['RVERSION']
require 'redis'

puts Process.pid
puts Redis::VERSION

ansulev

# Install Arch Linux with full encrypted btrfs subvolume inside luks
# Hardware: BIOS system, Intel GPU, Nvidia Optimus, Toshiba SSD, Wifi
# Please adjust for your needs.
# filename: install-arch-linux-on-btrfs-subvolume-inside-luks.txt
# The official guide: https://wiki.archlinux.org/index.php/Installation_Guide

# Download the archiso image from https://www.archlinux.org/download/
# Copy to a usb-drive
dd bs=4M if=archlinux.iso of=/dev/sdx status=progress oflag=sync # on linux

kgilles

# NOTE: Gender is something these countries use to calculate the serial/individual number(making them even or odd)
# It is not taken into consideration in this snippet but the generated numbers are still valid
require 'date'

age = 21 # Whatever you want it to be

# Randomize month and day equal to, or lower, than the current month
# to make sure the generated birth month and day has occurred in <current_year>
t = Time.new
year = t.year - age

tinhnq

1) Setup Server on Vultr
Select “create New Server(e.g. 123.123.123.123)”, select “Ubuntu 14.04 LTS”
Once your server has been created, wait for installation to complete.
SSH into your Server as root and run the following commands:
# login server by SSH
ssh root@dokku.me
# Updating apt-get
sudo apt-get update        # Fetches the list of available updates
sudo apt-get upgrade       # Strictly upgrades the current packages
sudo apt-get dist-upgrade  # Installs updates (new ones)