Rico Mariani, the .NET Performance guru, had an article on this very subject. It’s not as simple as one might suspect. The basic advice is this: If your pattern looks like: x = f1(…) + f2(…) + f3(…) + f4(…) that’s one concat and it’s zippy, StringBuilder probably won’t help. If your pattern looks like: … Read more
Since version 1.7.0, NumPy has a choice function that supports probability distributions. from numpy.random import choice draw = choice(list_of_candidates, number_of_items_to_pick, p=probability_distribution) Note that probability_distribution is a sequence in the same order of list_of_candidates. You can also use the keyword replace=False to change the behavior so that drawn items are not replaced.
You can use built-in profiling support: after launching vim do :profile start profile.log :profile func * :profile file * ” At this point do slow actions :profile pause :noautocmd qall! (unlike quitting noautocmd is not really required, it just makes vim quit faster). Note: you won’t get information about functions there were deleted before vim … Read more
Warning: timeit results may vary due to differences in hardware or version of Python. Below is a script which compares a number of implementations: ambi_sieve_plain, rwh_primes, rwh_primes1, rwh_primes2, sieveOfAtkin, sieveOfEratosthenes, sundaram3, sieve_wheel_30, ambi_sieve (requires numpy) primesfrom3to (requires numpy) primesfrom2to (requires numpy) Many thanks to stephan for bringing sieve_wheel_30 to my attention. Credit goes to Robert … Read more
As others have said, the issue is the store to the memory location in the array: x[i][j]. Here’s a bit of insight why: You have a 2-dimensional array, but memory in the computer is inherently 1-dimensional. So while you imagine your array like this: 0,0 | 0,1 | 0,2 | 0,3 —-+—–+—–+—- 1,0 | 1,1 … Read more
Use the operation that best describes what you are trying to do. If you are treating the number as a sequence of bits, use bitshift. If you are treating it as a numerical value, use division. Note that they are not exactly equivalent. They can give different results for negative integers. For example: -5 / … Read more
For any optimization, it’s always best to test, test, test. I would try at least sorting networks and insertion sort. If I were betting, I’d put my money on insertion sort based on past experience. Do you know anything about the input data? Some algorithms will perform better with certain kinds of data. For example, … Read more
Chrome Developer Tools has an Audits tab which can show unused CSS selectors. Run an audit, then, under Web Page Performance see Remove unused CSS rules
It’s pretty intuitive: A program is CPU bound if it would go faster if the CPU were faster, i.e. it spends the majority of its time simply using the CPU (doing calculations). A program that computes new digits of π will typically be CPU-bound, it’s just crunching numbers. A program is I/O bound if it … Read more