Category Archives: UDFs

Finding Prime Numbers with Excel, and using Array Formulas

Posted on 18/11/2008 by dougaj4

Download Primes.zip. Several of the puzzles at Project Euler (see previous post) require the finding of prime numbers, for instance what is the 10,001th prime number?  Searching the Web for some ready made solutions I found this array formula at … Continue reading →

Posted in Arrays, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , | 28 Comments

Reinforced Concrete Section Analysis 7 – rectangular sections

Posted on 05/11/2008 by dougaj4

Previous post The spreadsheets presented in earlier posts in this series have been simplified for use with rectangular sections with two layers of reinforcement.  The functions EStress (for elastic analysis of stresses, strains and crack widths) and UMom (for the … Continue reading →

Posted in Beam Bending, Concrete, Newton, UDFs | Tagged , , , , , | 3 Comments

A Question of Spelling

Posted on 01/11/2008 by dougaj4

The Excel VBA routine below will check the spelling of the text in the current selected cell, and return either TRUE or FALSE in the adjacent cell to the right: Sub SpellChecksub() Dim Checkword As String, Result As Boolean Checkword … Continue reading →

Posted in Excel, UDFs, VBA | Tagged , , | 15 Comments

Drawing in Excel 6 – getting shape properties

Posted on 17/09/2008 by dougaj4

Previous post One of the less than useful new “features” of Excel 2007 is that its macro recorder no longer records operations on shapes, which removes the easiest way to discover the exact names of shape properties, and how to manipulate … Continue reading →

Posted in Drawing, Excel, UDFs, VBA | Tagged , , , , | 5 Comments

Linking Excel to C – 3; Avoiding bottlenecks

Posted on 08/09/2008 by dougaj4

The previous post in this series included a C dll to solve cubic polynomial equations that could be called from VBA.  The performance of this routine is compared with a VBA routine using a similar algorithm in the sceenshot below (rows … Continue reading →

Posted in Arrays, Excel, Link to dll, UDFs, VBA | Tagged , , , | 2 Comments