On 08/10/2018 10:55 AM, Alan Hewat wrote:
Thanks Henk (and Bob). It's a story that must be quite common in science. Humans
like to simplify, and identify with heros. Humanity teaches us that we stand on
the shoulders of others. Few discoveries, especially in science, are made by a
single individual.
Profile Refinement was perhaps an idea "whose time had come" with the
application of computers. But the stroke of genius was to refine the structure
directly from the data points, rather than first refine structure factors. Even
that may have been simply because computers at that time could only handle a
limited number of parameters.
A fascinating story. Alan.
Henk,
I agree with Alan that you told a fascinating story, and not what I was
expecting. It is always a temptation to give yourself more credit than an
unbiased observer might allow. This case represents a most egregious instance.
To show the state of early computing, one of the graduate students in
Crystallography in the Geology Department at the University of Minnesota when I
started in 1962, was awarded a PhD for writing a computer program to calculate
powder patterns! This was on a Univac 1103 with capabilities similar to that of
the computer described in Bob and Henk's article. With such limited
capabilities, you had to choose the problem with considerable care.
By the time I graduated 5 years later, the University had a CDC 6600
"supercomputer", which had the blazing speed of 3 megaFLOPS (double precision)!
For comparison, this is roughly the performance of an x86 machine with an 0.7
GHz clock!!
Larry
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