Joblib is a Python library created by the developers of scikit-learn. Its main mission is to improve the performance of long-running Python functions. Joblib achieves the improvements through caching and parallelization using multiprocessing or threading under the hood. Install Joblib as follows:

$ pip install joblib
$ pip freeze|grep joblib
joblib==0.8.2

We will reuse the code from the previous example only changing the parallel() function. Refer to the joblib_demo.py file in this book's code bundle:

def parallel(nprocs):
    start = timeit.default_timer()
    Parallel(nprocs)(delayed(simulate)(i) for i in xrange(10, 50))

    end = timeit.default_timer() - start
    print nprocs, "Parallel time", end
    return end

Refer to the following plot for the end result (the number of processors is hardware-dependent):