How do I profile a Python script?
How do I profile a Python script?
performance
Why JSF calls getters multiple times
This is caused by the nature of deferred expressions #{} (note that “legacy” standard expressions ${} behave exactly the same when Facelets is used instead of JSP). The deferred expression is not immediately evaluated, but created as a ValueExpression object and the getter method behind the expression is executed everytime when the code calls ValueExpression#getValue(). … Read more
Big O, how do you calculate/approximate it?
I’ll do my best to explain it here on simple terms, but be warned that this topic takes my students a couple of months to finally grasp. You can find more information on the Chapter 2 of the Data Structures and Algorithms in Java book. There is no mechanical procedure that can be used to … Read more
Why is processing a sorted array faster than processing an unsorted array?
You are a victim of branch prediction fail. What is Branch Prediction? Consider a railroad junction: Image by Mecanismo, via Wikimedia Commons. Used under the CC-By-SA 3.0 license. Now for the sake of argument, suppose this is back in the 1800s – before long-distance or radio communication. You are the operator of a junction and … Read more
String vs. StringBuilder
Yes, the performance difference is significant. See the KB article “How to improve string concatenation performance in Visual C#”. I have always tried to code for clarity first, and then optimize for performance later. That’s much easier than doing it the other way around! However, having seen the enormous performance difference in my applications between … Read more