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git config --global alias.lg "log --graph --pretty=format:'%Cred%h%Creset -%C(yellow)%d%Creset %s %Cgreen(%cr) %C(bold blue)<%an>%Creset'"

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function linspace(shape, start, end, options) {
    /*
     If we use ndarray-linspace package,
     it returns a ndarray with dtype='array',
     but this dtype cannot be used by ndarray-tile package, it needs 'float'.
     So we need to transform dtype manually.
     */
    let tmp = linspace(ndarray([], shape), start, end, options);
    return reshape(ndarray(new Float64Array(tmp.data)), shape);
}

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-- from [StackOverflow](https://stackoverflow.com/questions/4597820/does-haskell-have-list-slices-i-e-python)
takeStep :: Int -> [a] -> [a]
takeStep _ [] = []
takeStep n (x:xs) = x : takeStep n (drop (n-1) xs)

slice :: Int -> Int -> Int -> [a] -> [a]
slice start stop step = takeStep step . take (stop - start) . drop start

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Options[plotGrid] = {ImagePadding -> 40};

plotGrid[l_List, w_, h_, opts : OptionsPattern[]] :=
   Module[{nx, ny, sidePadding = OptionValue[plotGrid, ImagePadding],
      topPadding = 0, widths, heights, dimensions, positions, frameOptions
      = FilterRules[{opts}, FilterRules[Options[Graphics], Except[{ImagePadding,
      Frame, FrameTicks}]]]},
      {ny, nx} = Dimensions[l];
      widths = (w - 2 sidePadding) / nx Table[1, {nx}];
      widths[[1]] = widths[[1]] + sidePadding;

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fib[n_] := Which[n == 0, 0, n == 1, 1, n > 1, fib[n - 1] + fib[n - 2]]

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Clear["Global`*"]

GreenChristoffelEquations[{ qx_, qy_, qz_ }] := {{
        c11 qx ^ 2 + c44(qy ^ 2 + qz ^ 2), (c12 + c44) qx qy, (c12 + c44) qx qz
    }, {
        (c12 + c44) qx qy, c11 qy ^ 2 + c44(qz ^ 2 + qx ^ 2), (c12 + c44) qy qz
    }, {
        (c12 + c44) qx qz, (c12 + c44) qy qz, c11 qz ^ 2 + c44(qx ^ 2 + qy ^ 2)
}}

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def iter_islast(iterable):
    """
    iter_islast(iterable) -> generates (item, islast) pairs

    Generates pairs where the first element is an item from the iterable
    source and the second element is a boolean flag indicating if it is
    the last item in the sequence.

    Referenced from
    `here <http://code.activestate.com/recipes/392015-finding-the-last-item-in-a-loop/>`_.

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def listdir_nohidden(path):
    for f in os.listdir(path):
        if not f.startswith('.'):
            yield f

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#!/usr/bin/env python -u -i

import os
import re

import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
from matplotlib.ticker import ScalarFormatter

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(* Taken from http://mathworld.wolfram.com/Jacobian.html *)
JacobianMatrix[f_List?VectorQ, x_List] := Outer[D, f, x] /; Equal @@ (Dimensions /@ {f, x})
JacobianDeterminant[f_List?VectorQ, x_List] := Det[JacobianMatrix[f, x]] /; Equal @@ (Dimensions /@ {f, x})