README_dsyevj3

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Numerical diagonalization of hermitian 3x3 matrices
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This set of algorithms is intended to numerically solve the eigenvalue and
eigenvector problem for symmetric or hermitian 3x3 matrices.


Installation
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The algorithms can not be used as standalone tools. They are intended
to be copied into your own programs and used there according to your
specific needs. The tarball that you have downloaded contains the main
algorithm (zheevX3) as well as all required helper functions.

If you have downloaded the complete library, the package also contains
a sample Makefile to generate a shared library that can be linked dynamically.

If you are using the C version of the code, please note that it follows
the C99 standard, which includes the data type double complex and thus
provides support for complex numbers. To correctly compile this code,
you may have to use special compiler options. For the GNU C compiler,
this option is -std=c99. If you intend to use a different compiler,
please check its documentation for the appropriate settings.

For optimum performance, we recommend switching on all optimizations
provided by your compiler. For the GNU compilers, this is done by
using the option -O3. To get an additional speed bonus, you might
consider using options such as -ffast-math to enable faster, but
non-standard floating point arithmetic. It should usually be safe to do
so, but there is no experience on how the code performs under such
circumstances.


Terms of Use / License
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These algorithms are free software, covered by the GNU Lesser
General Public License (see file COPYING). However, since they have
been developed mainly for academic use, the author would appreciate
being given academic credit for it. Whenever you use this software
to produce a publication or talk, please cite the following reference:

Joachim Kopp
Numerical diagonalization of hermitian 3x3 matrices
arXiv.org preprint: physics/0610206
Int. J. Mod. Phys. C19 (2008) 523-548
         

Availability
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This software, as well as possible updates, is available from the
following URL:
   http://www.mpi-hd.mpg.de/personalhomes/globes/3x3/


Bug reports / Contact
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Although this software has been thoroughly tested, we cannot guarantee
that it is free of bugs. Hence, bug reports, comments, and suggestions
are always welcome. If you want to contact the author, you can do
so under the following email-address:
  jkopp@fnal.gov