Combining two-point lod scores (FASTMAP)

Dr. David Curtis dcurtis at
Thu Jul 23 11:36:36 EST 1992

I've had problems posting this - apologies if it appears more than once.

I have been working on an algorithm to combine two-point lod scores to
get a quick approximation to the multipoint lod. I have now come up with
something which (in my opinion) performs reasonably well. It is
certainly extremely fast compared to LINKMAP, and generally produces an
unbiased approximation with an error that may be acceptable for many
applications. Certainly I have found it useful in carrying out my own
exploratory analyses, though I might want to check any crucial results
with LINKMAP before publishing them.

The algorithm has been submitted to Human Heredity, but I have now got
to the stage where I am prepared to distribute FASTMAP, the program
which implements it, more widely so that other people can evaluate its
performance in practice (and hopefully also benefit from the use of it). 
The DOS executable and C source file have been submitted to Dan Davison's
gene-server collection, where it is available as follows:

 62484 Jul 18 12:01 fastmap.aa   
 62524 Jul 18 12:01 fastmap.ab
 51210 Jul 18 12:01

These files have been PKZIP'ed, uuencoded and shar'ed. As well as being
available from the mail-server at gene-server at they have also
been forwarded to mirror sites at the EMBL, and uibio
archives. I would prefer that people obtained it from an archive, but
anyone who has difficulty can contact me directly. I would very much
welcome feedback concerning its performance.

Please note that the graph-drawing program with which it interfaces,
EASIGRAF, is an updated version of the EASIPLOT program available from
the same archives. The latter can be used instead fo rthe present. I aim to
get round to posting EASIGRAF and an updated version of the EASISTAT
package to these archives shortly.

Incidentally, for those using PEDRAW, version 1.4 has also been posted
as pedraw14.aa to

Dave Curtis

Academic Department of Psychiatry,    Janet:       dcurtis at UK.AC.CRC
St. Mary's Hospital,                  Elsewhere:   dcurtis at CRC.AC.UK
Praed Street, London W2.              EARN/Bitnet: dcurtis%CRC at UKACRL
Tel 071-725 1993                      Usenet: ...!mcsun!ukc!mrccrc!D.Curtis

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