Evert Rol evertrol

Makefile cheat sheet

Mostly geared towards GNU make

I've used ->| to indicate a tab character, as it's clearer to read than ⇥

Set a target, its dependencies and the commands to execute in order

target: [dependencies]
-&gt;|

Prerequisities:

A reasonably new Ubuntu or Ubuntu-derived system. This helps matching the required system packages to be installed, that are used to build Python form source later on.
Single user usage of Python packages. That is, you are not the system administrator that installs packages for multiple users.

Don't use sudo to install Python or a Python packages. There is no need for it, and it can only mess up your system. sudo is only to be used to update the system, or install helper packages (libraries, compilers) to build Python or any package (such as NUmPy) from source, through the system package manager (such as apt, dnf or pacman).

That also means there is no need to install (system) packages such as python(3)-numpy or python(3)-scipy, or even python(3)-pip. In fact, these could possibly even be uninstalled, and no harm would come from it. But if they are installed, let them be. They should not interfere with user-installed versions later on.

Virtual environments are onl

Configuration files

Configuration files are a practical, and probably essential, thing to have your code run flexibly. A good configuration can prevent lots of tiny (or large!) errors, and make it easier for other people to use your code (or you yourself if you haven't used the code for a while).

Generally, there will be configuration files, to change things like

starting configuration (of a simulation)
output file names, directories or formats
what to calculate or process (steps to take, steps to skip)
what to output (some calculated parameters may not be interesting for most calculations)

	*~
	*.pyc

	.hg
	.hgignore

	<!DOCTYPE html>
	<html>
	<head><meta charset="utf-8" />
	<title>Thumbnail classification</title><script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.1.10/require.min.js"></script>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script>

	<style type="text/css">
	/*!
	*
	* Twitter Bootstrap

	/// Rust Fibonacci one-liner using `fold`
	///
	/// Not very practical: only for one time use,
	/// since it will have to re-calculate all terms again and again
	/// if used in a loop to create multiple items.
	/// The use of `_` also suggests this is not an ideal solution.
	fn main() {
	let n = 10;
	let x = (0..n).fold((0, 1), \|x, _\| (x.0+x.1, x.0)).0;
	println!("{}: {}", n, x);

	2018-10-16 08:43:28,966 UTC [50059] INFO esmvaltool._main:123
	______________________________________________________________________
	_____ ____ __ ____ __ _ _____ _
	\| ____/ ___\|\| \/ \ \ / /_ _\| \|_ _\|__ ___ \| \|
	\| _\| \___ \\| \|\/\| \|\ \ / / _` \| \| \| \|/ _ \ / _ \\| \|
	\| \|___ ___) \| \| \| \| \ V / (_\| \| \| \| \| (_) \| (_) \| \|
	\|_____\|____/\|_\| \|_\| \_/ \__,_\|_\| \|_\|\___/ \___/\|_\|
	______________________________________________________________________

	ESMValTool - Earth System Model Evaluation Tool

	name: base
	channels:
	- conda-forge
	- defaults
	dependencies:
	- iris=2.2.0=py36_1003
	- iris-sample-data=2.1.0=py_0
	- cftime=1.0.3.4=py36hd352d35_1001
	- numpy=1.16.2=py36_blas_openblash1522bff_0
	- pandas=0.23.4=py36h637b7d7_1000

	julia> VERSION
	v"1.3.0"

	julia> # Julia documention on array) comprehensions and generator expressions:
	julia> # https://docs.julialang.org/en/v1/manual/arrays/#Comprehensions-1
	julia> # https://docs.julialang.org/en/v1/manual/arrays/#Generator-Expressions-1

	julia> # The code below uses generator expressions
	julia> # Double list comprehension for the first fifty-one terms of the power series of the exponential function
	julia> sum(prod(1/i for i in 1:n) for n in 1:50) + 1

	# Notes about values in the TOML config file:
	# - strings should always be quoted. Multi-line strings are possible
	# using triple-quotes, but should not be necessary in this config file
	# - floating point values require a decimal dot, or an exponent (or
	# both). Otherwise, they are interpreted as integers.
	# More information about the TOML config format: https://github.com/toml-lang/toml


	# Scenarios to use.
	# This defines only the names and epoch.