Creating and editing a data set

21

1. Click on the working tab to activate the working data form.

2. Select 

File|Export.

When

 File | Exit

 is selected, if a data set has been altered in any way, but not

saved, you will be asked if you would like to save the data.

4.5

Maximum size of the data set and computation speed

In CAP 3.0 new array handling technology has been introduced to enable the

analysis of very large data sets.

Theoretically, the size of the input data matrix is unlimited although, in practice,

the memory resources of the PC is usually the limiting factor. In tests we have run

CAP with a data array of 5000 species x 5000 samples without difficulty.

Because of its unusual computational requirements, which involves the

generation of new data items in the form of pseudospecies, TWINSPAN is more

demanding in memory usage. The maximum size of the data set whilst running

TWINSPAN is therefore likely to be slightly smaller than for the other multivariate

methods. It should still easily be sufficient for most users  needs, however.

Our new approach to data handling means that on a reasonably modern PC,

most of the computation, even on very large data sets, can be completed within a

few seconds.  All computations with data sets of up to 100 samples by 100

species are usually almost instantaneous.

If you do run into speed problems with very large data sets, it will generally be

improved if there are no other Windows applications running at the time.

Copyright 2004, PISCES CONSERVATION LTD