How to do Distributed Calculations in Excel

Question

A number of years ago I implemented an asynchronous peer-to-peer Message-Oriented-Middle-ware that was very friendly to use in Excel VBA, and I find myself again needing to do lots of calculations which could be trivially distributed, if I had the mechanism.

I could re-implement the MOM layer, but I'd prefer to use a third party product if one existed.

My requirements are these:

• to be able to send messages easily from Excel VBA and VB6,
• to have a resource discovery mechanism to find the calculation services,
• to have asynchronous message sends (I don't want to lock up Excel while the calculation is being done),
• to provide a queuing mechanism so I can have multiple servers doing the work easily,
• to have low admin for setup

Can anyone suggest anything?

Many thx

-- DM

Answer 1

The only question I can offer an answer to is the emailing. Ron DeBruin has excellent examples on his site for VBA code to email.

http://www.rondebruin.nl/sendmail.htm

Answer 2

RESTFul Web Services are easy to use from Excel VBA. You can use a reference to MSXML2 or WinHttp - Sounds like you want to use in Async mode so as not to block the Excel UI.

Start with something simple:

• Simple discovery (scan your subnetfor worker nodes).
• Divide your task up.
• Share out tasks.
• Wait or poll for results.
• Update cells with new results.
• If any sub task takes too long round robin again.

Nice to have visual indication on cells pending results.

These links may help you.

Peer-to-Peer Programming with WCF and .NET Framework 3.5

Peer-to-Peer Programming

MPAPI - Parallel and Distributed Applications Framework

Answer 3

The next release of Microsoft Windows Server 2008 HPC edition includes something called "Excel Runner" which is specifically designed to deal with the kind of problem you are describing.