Showing posts from August, 2011

How do you use NAG in Excel?

For years NAG has considered Excel users as a group with certain needs for good numerical algorithms. Nowadays Excel is the industry-standard for spreadsheets, but it is not a statistical package nor is it a numerical analysis tool. That’s why Excel users come to NAG and ask how our accurate, robust and efficient NAG Library can be utilised in Excel.There are a few ways in which the Library can be called in Excel:xls/xlsm spreadsheet and VBAThe most popular, widely used way: NAG and Excel page describes how to do it with the help of technical papers and downloadable examples. Basically you create a new spreadsheet and add VBA code to it. NAG has created VBA Declaration Statements which provide the bridge between NAG and Excel- the user just has to add the declaration file to a VBA module and the NAG DLL becomes visible to Excel & VBA. From this moment on you can create macros that will, for example, read data from an external data file, process it in VBA and then display the resul…

What is this HPC thing?

I’m sure something like this is familiar to many readers of this blog. The focus here is HPC, but there is a similar story for mathematicians, numerical software engineeers, etc.

You've just met an old acquaintance. Or a family member is curious. Or at social events (when social means talking to real people not twitter/facebook). We see that question coming. We panic. Then the family/friend/stranger, asks it. We freeze. How to reply? Can I get a meaningful, ideally interesting, answer out before they get bored? What if I fail to get the message across correctly? Oops, this pause before answering has gone on too long. Now they are looking at me strangely. They are thinking the answer is embarrassing or weird. This is not a good start.

The question? “What do you do then?” Followed by: “Oh! So what exactly is supercomputing then?

The problem is that it usually takes a several slides or a few minutes of explanation to give a decent overview to a scientist who is new to HPC. Your q…

Seeing the good for the trees

We put a lot of effort into trying to ensure that our numerical libraries are available on the platforms that are most popular with our users. For each library, this leads to a proliferation of implementations, each of which is targeted at a specific combination of compute processor, operating system and compiler. The details of current implementations are on our website - for example, here is the list for the NAG Fortran Library, which also includes download links for each implementation. Although this list - which currently features forty-nine implementations - is an impressive array (and the fruits of a great deal of careful work on the part of our implementation team), its presentation could perhaps be viewed as being tricky to navigate by those who are searching for the appropriate implementation for their particular system.