Stuff I do

The problem After freshly installing bitcoin-qt - the de-facto bitcoin client - to a computer, it starts downloading "blocks" from the network. The last few (tens of) thousands of blocks are especially slow, and the client is using the disk heavily. Examining the disk usage closely with iostat showed that the disk utilization was 100%, but at a very low data rate. My disk can read and write about 150 MBytes/second if utilized properly, but bitcoin-qt could only write about one megabytes per second. (EDIT: thanks for the donation, you rock! :) )

How to write fast programs with numpy and python At first, I wanted to write a post about "how to write fast programs with python and numpy". After writing a few test cases it quickly turned out that the fast, numpy versions of tests are not only fast because of numpy, but because they use numpy "the right way". Let's see what does it mean.