New repository initialized by cvs2svn.
Initial revision
This commit was generated by cvs2svn to compensate for changes in r4,
which included commits to RCS files with non-trunk default branches.
Included a new environment variable LINEAR so that one can switch
between a specified velocity field and a full vortex computation.
Removed some old backup files and old utility files that are archived
elsewhere like in eccsvm_v5.73.
Removed comments from calls to partition and release_links in init.

Removed comments from calls to Create_Hierarchy and release_links in vel_field.

Added stream_fn.c for the new matrix vector approach to evaluating the
velocity field and its derivatives.

There are two lines of diagnostics in velocity.c to compare velocity
field information.

So far, everything seems to work on the test cases I've tried.
Performed some testing of velocity.c with the new stream-fn.c
routines.  Both agree.

Started checking the new stream-fn.c routines for veldev.c and found
that they do not agree.  When I check against exact solutions for the
axisymmetric case, it appears that the original veldev.c is in error!
I am sure that I certified veldev some time ago, but some bug may have
crept into the code.  The new stream-fn.c routines remove the
difficulty and simplify the process of coding these approximate stream
functions.
Added induced_v, a subroutine that will compute the velocity and all
its derivatives.  It should replace induced_vel and induced_veldev
eventually and it will allow curvature corrections as well.
Finished adding code to induce_v so that it will return velocity
curvature information.  Also, tested the code with axisymmetric
initial elements, and it appears that the rotations back into standard
coordinates work properly.  The subroutines in stream-fn.c are trusted
because they come from a standalone program that was certified
separately.

Added curvature information to the blobparms data structure.  These
fields are reset in dpos_vel and dpos_vel_fast with all the other
velocity information.

To be done:

(1) Curvature corrections in dpos_vel_gen?  Perhaps this is needed
when merging elements.

(2) When dx==0 and dy==0, there is special code in MP_Direct.  Perhaps
this type of checking belong in induced_v.

(3) Of course, after the velocity field is computed, it needs to be
corrected using the curvature information.
Forgot to add into previous entry

(4) Include curvature terms in fast multipole summation.

Done.  Just finished adding this part to mpsum.  It needs to be tested
still.

Also, removed stream-fn.c calls from induced_vel and induced_veldev so
that the compile would be clean.  Eventually, it is likely that both
these subroutines will go away.

Modifications to global.h, mpcoeffs.c are just to fix the zip code in
the license.
Resolved conflicts between 5.76 and 5.78, and removed comment about a
problem in velocity.c.
Tested the whole velocity and derivative calculations on a Gaussian
distribution.  Everything works well.
Removed diagnostics.

Still to do: Add fourth order corrections to the velocity field.
Created vort_vort_interaction(i,j) routine to perform direct
interactions for dpos_vel, dpos_vel_fast and MPDirect[1-3].  This is
just to consolidate code and remove errors that might arise through
multiple implementations.
Just some cosmetic changes to vort_vort_interaction.
Completed and tested consolidatation of code using
vort_vort_interaction.  Removed all the commented code that it
replaced.

Added correct_vel_4() which adds velocity field curvature corrections
to the particle velocities.  This still will not work with the
distributed version.
Changed rk4internal.  Rather than checking for rapid reorientation
only once and then taking an RK4 step, we check at every step along
the way.  Rather than checking for rapid reorientation by looking at
|a^(-2) - a^2|, I do it by seeing if dta2 is finite.  This is in
response to nan's popping up which I believe happens when the system
is close to rapid reorientation.
Yet another stab at rk4internal...  There is still something wrong
with this approach.
Re-introduced regularization term in dtth calculation to remove the
need for checking of rapid reorientation.

Probably, one should add some code so that dth_regularize can be
defined by the user with a default value if the user specifies nothing.
Added code to allow the .ctl file to specify dtth_delta and turn on
and office fourth order corrections.  The first change has been
tested.  The second change has not been tested.