PAT for Windows will now handle larger numbers of atoms
In a recent student exercise we wished to simulate the pattern for a fragment
of a metal complex containing 39 carbon atoms, so as to show the effect
of combining the metal isotope pattern with the
12C/13C
pattern. This worked using Version 1.1 of PAT for Windows in 32-bit
Windows 7 and in Windows XP PCs, but crashed the PAT program in 64-bit
Windows 7
-
In repeatedly convoluting low intensity peak heights by the low relative
abundance of 13C, numbers of negligible size were produced,
generating an underflow condition
-
To cure this bug, I put a trap in the convolution routine to prevent underflows,
to make Version 1.2 of PAT
-
Version 1.2 of PAT was published in the download package on 22 November
2011
-
Further testing showed that for very large numbers of atoms of certain
other elements, the program could still crash because of overflows
-
I then replaced the underflow trap by a more general method, which normalised
the pattern after each atom of each element. On modern PCs, the extra
time taken was unnoticeable
-
This made Version 1.3 of PAT, which was put into the download package on
1 December 2011
-
Version 1.3 of the PAT for Windows program, containing this bug fix,
will now calculate isotope patterns for fragments containing up to 99 atoms
of each element, provided that the highest mass number of the isotope pattern
is less than 10000, and will run on all the supported platforms
-
The version number of a running copy of PAT may be found by clicking Help,
About PAT
No one reported the bug in version 1.1, so perhaps no one tried to use
it in 64-bit Windows 7 for fragments containing more than about C17.
If you find any bugs, I should be grateful if you would tell me about them.
My email address may be found below, or at the bottom of the ReadMe web
page, or in the program by clicking Help, Setup and scrolling to the bottom
of the text
B.W. Tattershall
Newcastle University, England
December 2011
Email: Bruce.Tattershall@ncl.ac.uk