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Previously, matrix a has been kept on the device at the end of bandred
and then copied to host later in redist_band (called from tridiag_band).
However, it seems to be more convenient to do it at the end of bandred
(since it has to be done anyway). Band to tridi is thus now not using a
on the device at all.  However, we keep it in the interface, sice it
might be usefull in the future.

elpa2_trans_ev_band_to_full_template

Anything if it makes Andreas happy :)

This is a bit cumbersome, as it involves yet another abstract
intermediate type, but necessary due to language limitations.

It could happen that ELPA stopped with an error but an exit code "0"
was given, i.e. one could assume everything was fine when it was not!
Now each Fortran "stop" was replaced with "stop 1" to prevent this

This closes issues #48

library

It the configure option "--enable-single-precision" is specified,
ELPA will also be build for single precision usage. The double precision
and single precision will be available at the same time with names
"solve_evp_real_1stage_double" or "solve_evp_real_1stage_single" and
so on...

This change immplied some major refactoring of the ELPA code:
1.) functions/procedures had to be renamed with suffix "_double"

2.) If necessary the same functions have to be available with suffix
"_single"

3.) Variable kind definitions have to be consistent with the
intented use

To avoid uneccessary code duplication this is done (most of the time)
with preprocessor string substitution.

The documentation has been updated.

NOT SUPPORTED are at the moment:

- single precision usage of ELPA2 with kernels, others than "generic"
  and "generic_simple"

- single precision usage of GPU

The configure flag "--enable-shared-memory-only" triggers a build
of ELPA without MPI support:

- all MPI calls are skipped (or overloaded)
- all calls to scalapack functions are replaced by the corresponding
  lapack calls
- all calls to blacs are skipped

Using ELPA without MPI gives the same results as using ELPA with 1 MPI
task!

This version is not yet optimized for performance, here and there some
unecessary copies are done.

Ths version is intended for users, who do not have MPI in their
application but still would like to use ELPA on one compute node

With the configure option "--enable-single-precision" ELPA1 is build
with single-precision (half-words) only.

The best precision in single-precision (float or complex) is
2^-23 ~ 1.2e-7. The accuracy of the error residual of ELPA1 in
single-precision mode is of the order 1e-4 to 1e-5. The orthogonality of
the EV's is fullfilled up to about ~1e-6.

Thus the precision of ELPA1 in single-precision mode is roughly 100 -
1000 times less than the best achievable precison. This is consistent
with the double-precision mode, where also a factor of 100 - 1000 less
precision than the theoretical best one is found.

The float EVs are identical to the double EVs to at least 1e-2, the
precision of the EVs is thus about 1e-7/1e-2 = 1e5 times lower than the
best theoretical precision. If the same holds for the double precision
calculations, this implies that the double precision results can also
be only trusted on the level 1e-11 (5 orders of magnitude larger
than the best theoretical precision)

The best speed-up compared to the double precision calculation is
a factor of two. This is by far not achieved yet, since the singl
precision version is not at all optimized at the moment

All variables (real, integer, complex) are now declecared with the
appropiate kind statement. The definition of the kind types is done
in src/mod_precision.f90

To ensure interoperability with C, the kind types are decleared via
iso_c_binding to C variables

- the contact email is now: elpa-library@mpcdf.mpg.de
- the official website is now hosted at http://elpa.mpcdf.mpg.de

The Rechenzentrum Garching (RZG) has been renamed into
the Max Planck Computing and Data Facility (MPCDF).

This is reflected now in the adapted headers.

In the near future, all references to the ELPA webside and
the ELPA email will also be adapted.

complex cases

Create automatically two independent routines for real and complex
valued matrices