brightway2-calc / bw2calc /

# -*- coding: utf-8 -*
from bw2data.utils import MAX_INT_32
import numpy as np
import itertools

def indexer(array_from, array_to, mapping):
Chosen algorithm is faster than using rankdata, or simple iteration.
Modifies numpy arrays in place.

map(dict.get, data) seems faster, but doesn't work with missing values.

Setup code to try new approaches::

    from numpy import *
    from time import time
    a = random.random_integers(5000, size=100000)
    indices = sorted(list(set([int(x) for x in a])))
    mapping = dict(zip(indices, range(len(indices))))
    b = zeros(a.shape[0])

    array_to[:] = np.array([mapping.get(x, MAX_INT_32) for x in array_from])

def dicter(array):
Create dictionary from the sorted, unique values in a numpy array

Already more than fast enough. Setup code for other approaches::

        %%timeit import numpy as np; array = np.random.randint(0, 5000, size=50000)
        dict(zip(np.sort(np.unique(array)), itertools.count()))

    return dict(zip(np.sort(np.unique(array)), itertools.count()))