In case some of you may have been familiar with Bob Carruthers, I
have included the following obituary with permission of David Watkin
( david.wat...@chem.ox.ac.uk )
John Robert (Bob) Carruthers.
15 May 1945 - 17 January 2009
Bob graduated from St Edmund Hall (Oxford) having completed his Part II
year doing copper chemistry with Francis Rossotti. He worked for his D.
Phil. (still on copper chemistry) with Keith Prout and Francis, and it
was during this work that he became interested in crystallography.
For one of the materials he worked on, aquo(maleato)copper(II), he
observed "When the diffraction pattern was indexed, it became apparent
that the crystals were unlikely to be orthorhombic, as a strange set of
absences were found". The crystals were twinned. "overlapped reflections
were arbitrarily assigned half the measured intensity until a program
was written which would include both components in the least squares".
"as there was not sufficient space [memory] it was necessary to rewrite
the [AUTOCODE] program in [English Electric Leo Marconi] KDF9 machine
language". AUTOCODE was a symbolic language, rather like a simplified
FORTAN. Machine languages are basic to the electronics of the computer,
and the programmer has the power and the responsibility of working
hands-on with every memory location, even to the extent of synchronising
the calculations with the revolutions of the bulk storage devices. So
began Bob's life with computers, and his exceedingly productive
partnership with John Rollett.
Immediately after writing his DPhil thesis in 1969, Bob was awarded a
fellowship from the Accademia Nazionale dei Lincei in collaboration with
the Royal Society which enabled him to work in Rome. There, he set about
working with Riccardo Spagna re- implementing the Rollett AUTOCODES in
FORTRAN. This program included features such as "riding" and rigid-body
constraints, and some of the underlying data-structure can still be
found in CAOS (Cerrini S. & Spagna R. (1977) Crystallographic software
for a mincomputer, IV Eur. Crystallgr.Meet., Oxford, UK, Abstract A-
212).
On Bob's return to Oxford he worked with Rollet and Prout, again
re-writing the program from scratch but building upon his experiences in
Rome. This new program, called CRYSTALS, could handle up to 9 twin
components and had a good range of restraints (including facilities now
often called SIMU and DELU). Perhaps the most novel feature was
"user-defined restraints", in which the user could define their own
equation of restraint as part of the input data, which was then
analytically differentiated by CRYSTALS. The equation parser and
differentiating engine were all written in beautiful FORTRAN, and are
still working, largely unmodified, in the current version of CRYSTALS.
Bob's attitude to programming combined a meticulous attention to detail
with a far reaching ability to plan on an expansive scale.
After his Post Doc, Bob started work for Oxford University Computing
Service, writing software for data-archiving. However, he continued to
work on CRYSTALS whenever he could, and completely re-wrote the
underlying data management for a third time when the university upgrade
its mainframe to an International Computers Limited (ICL) 2980.
In about 1979 Bob left Oxford to work for Control Data Corporation,
implementing meteorology programs on their supercomputers. Apart for a
brief period in the 1980's when he worked with Keith Davies at Chemical
Design, Bob has spent most of his career implementing very large FORTRAN
program systems, and in recent years modernising massive legacy
packages. Weather forecasting may have profited from his work, but there
is no doubt that crystallography lost an outstanding programmer when Bob
left Oxford.
When not working with computers, Bob was a dependable drinking companion
and a formidable Bar Billiards enthusiast. Some of us still remember Bob
and George Sheldrick working with other young crystallographers to try
to drink the bar dry at ECM 4 in Oxford in 1977. His brilliance as a
scientist did not spoil his personality - he as always modest, amiable
and good fun
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-----------------------
Lachlan M. D. Cranswick
Contact outside working hours /
Coordonnees en dehors des heures de travail:
NEW E-mail / courriel: lachlanc *at* magma.ca
Home Tel: (613) 584-4226 ; Cell/mobile: (613) 401-6254
WWW: http://lachlan.bluehaze.com.au/
P.O. Box 2057, Deep River, Ontario, Canada, K0J 1P0
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