Monthly Archives: May 2011

A Quantum of Time – measuring time accurately.

If you want to do work on Excel performance stuff you need a method of timing things so that you can see whether one way of doing things is faster than another. Typically this requires 2 things: A method for … Continue reading

Posted in Calculation, VBA | 12 Comments

The XIPS Challenge – how fast does Excel calculate?

It used to be fashionable to measure computer speed in MIPS (millions of instructions per second). So I thought it would be interesting to: Find out how many XIPS (Excel Calculations per second) Excel could do on a modern PC. … Continue reading

Posted in Calculation | 3 Comments

Writing efficient VBA UDFs (Part 1) – It ain’t what you do it’s the way that you do it

Its fairly easy to write a User Defined Excel function using VBA: Suppose you want to write a function that calculates the average of a range of cells, but exclude from the average anything that is not a number or … Continue reading

Posted in UDF, VBA | 24 Comments

Fast Gini – calculating Gini coefficients in Excel efficiently

“The Spirit Level” is a very interesting book about the effects of inequality on health and wellbeing. It introduced me to the Gini coefficient, which is a number ranging from 0 to 1 that measures the degree of inequality in … Continue reading

Posted in UDF, VBA, XLL | 21 Comments