rrag

There are many tutorials and articles available online which explain functional programming. Examples show small functions, which are composed into others which again get composed. It is hard to imagine how it would all work, then come the analogies and then the math. While the math is necessary to understand it can be difficult to grasp initially. The analogies on the other hand, (at least for me) are not relatable. Some articles assume the reader knows the different terminologies of FP. Over all I felt it is not inviting to learn.

This introduction is for those who have had a tough time understanding those analogies, taken the plunge to functional programming but still have not been able to swim. This is yet another tutorial on functional programming

Terminology

Functions as first class citizens

Functions are first class means they are just like anyone else, or rather they are not special, they behave the same as say primitives or strings or objects.

DavidYKay

import cv2
import math
import numpy as np
import sys

def apply_mask(matrix, mask, fill_value):
    masked = np.ma.array(matrix, mask=mask, fill_value=fill_value)
    return masked.filled()

def apply_threshold(matrix, low_value, high_value):

alexpaluzzi

core-toolbar {
  font-family: RobotoDraft, sans-serif;
  background-color: #4058A3;
  box-shadow: 0px 3px 2px rgba(0, 0, 0, 0.2);
  color: #fff;
  font-size: 20px;
  font-weight: 400;
  height: 42px;
}

kitak

コマンドによる「負荷」の原因切り分け

この文章では、Linuxコマンド、sar, top, psを使って、一般的に負荷といわれるものの原因を切り分けることを目的とする。

そもそも負荷とは

「複数のタスクによるサーバリソースの奪い合いの結果に生じる待ち時間」を一言で表した言葉。OSのチューニングとは負荷の原因を知り、それを取り除くことにほかならない。

ボトルネックの見極め作業の大まかな流れ

• ロードアベレージ（処理を実行したくても、実行できなくて待たされているプロセス（CPUの実行権限が与えられるのを待っている、またはディスクI/Oが完了するのを待っている）の数）を見る

ry

// Based on http://bit.ly/215MBZ

function FailureDetector(ws) {
  // ws stands for window size.
  // How many heartbeat intervals we keep track of.
  this.ws = ws || 100;
  this.window = [];
  this.last = null;
}
exports.FailureDetector = FailureDetector;

bnoordhuis

http = require('http');
fs = require('fs');

fd = fs.openSync(__filename, 'r');
size = fs.fstatSync(fd).size;

server = http.createServer(function(req, res) {
        res.writeHead(200, {
                'Content-Length': size,
                'Content-Type': 'text/plain'