jeromer

#! /usr/bin/env python

# Tested on Postgres 9.5

import psycopg2
import datetime


conn = psycopg2.connect("dbname=sandbox user=postgres")
cursor = conn.cursor()

jeromer

Numbers Everyone Should Know

L1 cache reference                 0.5 ns
Branch mispredict                  5 ns
L2 cache reference                 7 ns
Mutex lock/unlock                  25 ns
Main memory reference              100 ns
Compress 1K bytes with Zippy       3,000 ns
Send 2K bytes over 1 Gbps network  20,000 ns
Read 1 MB sequentially from memory 250,000 ns

jeromer

# LICENSE: public domain

def calculate_initial_compass_bearing(pointA, pointB):
    """
    Calculates the bearing between two points.

    The formulae used is the following:
        θ = atan2(sin(Δlong).cos(lat2),
                  cos(lat1).sin(lat2) − sin(lat1).cos(lat2).cos(Δlong))

jeromer

# -*- coding: utf-8 -*-
import math

def calculate_orthodromic_distance(pointA, pointB):
    """
    Calculates the great circle distance between two points.
    The great circle distance is the shortest distance.
    This function uses the Haversine formula :
      - https://en.wikipedia.org/wiki/Haversine_formula