mpi_2005_fsu
mpi_2005_fsu,
"Introduction to MPI",
several introductory talks on
MPI, the Message Passing Interface,
presented at Florida State University, in October 2005.
These talks acquainted our
users with the the MPI library, the various local computing
clusters that supported MPI, and the job control necessary
to run MPI programs.
This was partly an attempt at publicity, but also an effort
to encourage our graduate students to look further into MPI,
as well as to prepare the groundwork for a talk on PETSC, to
be given by our visitor Jeff Borggaard.
The files include:
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computers.png,
an image of an early "computer" room at Harvard College
Observatory; the "computers" are women, doing various
calculations based on data from astronomical observations.
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cray_ymp.png,
an image of the Cray Y-MP supercomputer, a machine that
depended largely on vectorization and pipelining. High
speed required that the parts of the machine be very
tightly clustered. This meant a great deal of concentrated
heat, and so a major part of developing the Cray computers
involved imaginative solutions to the problem of pumping
coolant fast enough. The "benches" around the base of the
machine and the odd "aquarium" in the foreground
are actually parts of the cooling aparatus.
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eniac.png,
the ENIAC computer at Princeton, created in 1942, and setting
a record breaking speed of 5,000 additions in a second.
The machine was used to compute ballistics tables, but
John von Neumann insisted that it should be able to be
used to predict the weather. In 1950, he published work
suggestion how this should be done.
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europe_weather.png,
a schematic of the computational grid employed by Lewis
Richardson in his attempt to "predict" the weather using
data from 25 sample points in Europe. The task of computing
the weather 6 hours later, for just two of the points in
the grid, required six months of work, and the results
were disappointingly nonsensical.
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factory.png,
after the failure of his first weather calculation, Lewis
Richardson dreamed of a forecast factory or computational
orchestra of 64,000 players, seated in a spherical hall
representing the earth. Each player would have a slide rule
or adding machine, working on the predicted weather at their
local spot, and occasionally exchanging results with their
neighbors. A conductor in the center of the hall would
maintain order, using a bright light to point out players who
were going too fast or too slow for the others.
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fsu_logo.pdf,
a logo.
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harvard_mark.png,
the Harvard MARK computer, 50 feet long, 8 feet high, two feet deep.
A single addition, subtraction, transfer or clear of data required
3/10 of a second. Multiplication took at most 6 seconds, division
16, while the computation of a logarithm, exponential or sine
took 90, 66 or 60 seconds respectively. There was a staff of 10,
including 4 mathematicians, 4 operators, and 2 maintenance men.
-
hello_c.txt,
the text of a C program, using MPI, to say HELLO 4 times.
-
hello_cpp.txt,
the text of a C++ program, using MPI, to say HELLO 4 times.
-
hello_f77.txt,
the text of a FORTRAN77 program, using MPI, to say HELLO 4 times.
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matvec_f77_page1.txt,
piece 1 of a FORTRAN77 program, in which the "master" process
sends out data to the workers.
-
matvec_f77_page2.txt,
piece 2 of a FORTRAN77 program, in which the "master" process
receives results, and sends out more work.
-
matvec_f77_page3.txt,
piece 3 of a FORTRAN77 program, in which the workers receive
data from the master, compute results, and send them back.
-
nano.png,
a picture of Grace Hopper, holding one of her "nanoseconds".
This is a bit of cabling whose length is equal to the distance
that light (or an electric signal) can travel in a nanosecond.
She was forcefully making the point that the size of a computer
with a clockspeed of one gigahertz could be no bigger than
this length.
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wilma.png,
a weather map showing the predicted path of hurricane Wilma.
Although we snipe at the uncertainties of these predictions,
we think nothing of the fact that a reasonable reliable forecast
of tomorrow's weather can be computed and ready ...before tomorrow!
Last revised on 05 February 2025.