Fast Python
Source code for Fast Python (2020) by Chris Conlan
Paperback available for purchase on Amazon.
Code profiles
The following code profiles can be run as stand-alone scripts. They may or may not depend on explanation provided in the accompanying book.
- Binary search: binary_search.py
- Dictionary construction: build_dict.py
- Concatenating strings, string construction: concatenate_strings.py
- Counting the frequency of a value: count_occurrences.py
- Computing a cumulative sum: cumulative_sum.py
- The
inoperator and early stopping: early_stopping.py - Time series filters/convolutions: filters.py
- Find largest
kvalues in a list: find_top_k.py - List construction/declaration/flattening: flatten_lists.py
- Counting lines in a file: line_count.py
- Set intersection, finding matches in a list: match_within.py
- Matrix multiplication: matrix_multiplication.py
- Computing moving averages: moving_averages.py
- Counting frequency of a word in text: occurrences_of.py
- Looping through
pd.DataFrameobjects: pandas_loops.py - Sorting algorithms: sorting.py
- Low-level sorting algorithms: sorting_v2.py
- Adding a list of numbers: sum.py
Running them is simple ...
cd fast-python/src
python cumulative_sum.py
Profiling
All the profiles use a simple profiling module in src/utils/profiler.py. It produces tables and charts like the following.
np_fast_cusum
n = 56234132 values
t = 201.806 ms
n/t = 278653.8114 values per ms
np_fast_cusum
n = 100000000 values
t = 350.611 ms
n/t = 285216.7553 values per ms
...
function n_values t_milliseconds values_per_ms
0 slow_cusum 1 0.012 85.0196
1 slow_cusum 3 0.005 640.7530
...
14 slow_cusum 5623 1298.218 4.3313
15 slow_cusum 10000 4140.327 2.4153
...
30 slow_cusum_expanded 5623 1878.419 2.9935
31 slow_cusum_expanded 10000 5767.316 1.7339
...
62 python_fast_cusum 56234132 5727.162 9818.8478
63 python_fast_cusum 100000000 10939.993 9140.7733
...
94 pandas_fast_cusum 56234132 442.652 127039.2437
95 pandas_fast_cusum 100000000 780.461 128129.3962
...
126 numba_fast_cusum 56234132 139.602 402816.3295
127 numba_fast_cusum 100000000 236.445 422930.9936
...
158 np_fast_cusum 56234132 201.806 278653.8114
159 np_fast_cusum 100000000 350.611 285216.7553
I use the profiler frequently in my own work. It allows me to analyze the relationship between computational complexity and raw execution time pretty easily.
Dependencies
I have included a dependencies.txt, but you should be fine with a blank Python 3 environment followed by ...
pip install numpy pandas numba joblib matplotlib pillow
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