Monthly Archives: January 2013

Volatile Dependencies, Indirect Dependencies, False Dependencies – When Dependencies Don’t Work the Way You Think They Should

Its always a convenient shorthand to say that UDFs and formulas are recalculated when one of their arguments (or a precedent further upstream in the calculation chain) changes. But in fact that turns out to be a bit of an … Continue reading

Posted in Calculation, UDF, VBA | 3 Comments

The SpeedTools FILTER.IFS Function Design Part 3: Excel Data Types – Strange COUNTIF behaviour

The previous post discussed how Excel’s data types, and how FILTER.IFS was designed to handle them. Colin Legg suggested that a good starting point for the design choices could be what COUNTIF/SUMIF do. So here is an example of some … Continue reading

Posted in Calculation, Lookups, UDF, XLL | 5 Comments

The SpeedTools FILTER.IFS Function Design Part 2: Excel Data Types – When is a Number a String?

Excel Data Types Excel has only  4 or 5 native data types: Numbers (which can be formatted as Dates, Times, Currency, Integers, Doubles etc, but are all held internally as floating point doubles) Strings (Text including zero length strings like … Continue reading

Posted in Calculation, UDF, VBA, XLL | 2 Comments