** Changes to FElt from 1.0a to 1.3 (consecutive public releases) -

The following changes were made to the FElt syntax:
   1. addition of 'hinge' or 'h' as a keyword after the R[xyz]=
      token in a constraint to indicate a hinged DOF
   2. addition of a valid expression after the T[xyz]= or R[xyz]=
      token in a constraint to indicate a displacement boundary  
      condition.  Tx=c for examples is now equivalent to Tx=0.0.
   3. directions 'x','y', and 'z' are no longer valid.  This is
      the only backward incompatible change to the syntax.  Valid
      directions now include LocalX, LocalY, LocalZ, GlobalX,
      GlobalY and GlobalZ.  Check the element definitions in the
      user's manual to see what these things mean.
   4. you can now use sqrt() in expressions (just like you   
      you could use sin, cos and tan before).

The following bugs were fixed:
   1. a bug in xfelt which caused a core dump when you tried to
      draw a problem in 3d when it was only a 2d problem.
   2. a bug in the internal forces calculated for beams which always
      caused the second end moment to be printed as zero.
   3. several bugs in 3d beam elements including an error in the
      global <-> local transform matrix and a typo in the resolution
      of distributed loads.  I think they actually work now :-).
   4. not really a bug, but the directions of loads on beam elements'
      got straightened out and is probably a bit more consistent now.
   5. consistency amongst text commands, menu options and keyboard
      shortcuts was substantially improved.
   6. does the original user's manual count as a bug?  Well the new one
      should actually print on any old postscript printer, plus it
      contains a wealth of new information and is organized a whole lot
      better.

The following features were added:
   1. hinged DOFs, displacement boundary conditions.
   2. a simple, illustrative Timoshenko beam element.
   3. plotting of 2d planar stress fields with color imaging in velvet.
   4. plotting of the displaced structure in velvet.
   5. loads directed along the global coordinate axes on beams and beam3ds 
   6. a real file selection mechanism for velvet
   7. much improved, consistent, self-contained force, material, 
      load and constraint dialogs in velvet
   8. unified node and element edit/info dialogs
   9. a problem solution control dialog in velvet
  10. unified interface mechanism for all the dialogs, including tab groups
      and the ability to leave dialogs up throughout a work session
  11. translation include files and a built-in include path for cpp
      in felt and velvet.
  12. element numbering

** Changes to FElt from 1.3 to 2.0 (consecutive public releases) -

The following changes were made to the FElt syntax:
   All changes are completely backward copmpatible in this release - all
   original static problems will not need any modifications.

   1. t is now a valid token in expressions.  In a transient analysis problem
      it will stand for time in a force and be dynamically evaluated throughout
      the course of the simulation.  In static problems it will simply
      be evaluated at t=0 at startup and treated as a constant expression.
   2. valid expressions can now use the intrinsic functions hypot, log, 
      log10, ceil, floor, fmod, fabs, exp and pow.  They can also make use of
      the C style ternary if-then-else operator (t < 10 ? 15*t : exp(-0.03*t))
   3. a mechanism for time-magnitude pairs for discretized dynamic forces
      was added.
   4. an analysis= parameter in the problem description section to control what
      type of analysis is performed (static or transient) for that problem.
      The default is static if nothing is specified.
   5. an "analysis parameters" section to control the variables in 
      transient analysis problems - beta, gamma, and alpha are parameters
      in the HHT integration scheme.  duration and dt control the length
      and the time-step of the integration.  nodes= and dofs= control
      what node (and which DOFs at each node) are included in the output.
      mass-mode= controls what type of element mass matrices should be formed, 
      either consistent or lumped.
   
The following bugs were fixed:
   1. a couple problems with trying to solve problems (or do anything for that
      matter) after you'd deleted elements in velvet.
   2. the variable 'time' in lib/Widgets/post.c was renamed 'when' to avoid
      conflicts with some installations of gcc
   3. a local implementation of strdup was provided for systems that insist
      on being totally and solely ANSI and POSIX compliant.
   4. delete window hooks were added to the post-processing popups so you
      can now close them with the window manager and the entire program
      won't crash.
   5. a bug? ... well, the Fortran compiler was taken out as an option in
      the configuration - it's just too confusing for people as most people
      do not know what the extra libraries are that they need to link in.
 
The following features were added:
   1. transient analysis using Hilbert-Hughes-Taylor alpha variant of
      Newmark integration.  The C and M matrices are also assembled directly
      into a compact column representation.  Dynamic forces can be specified
      as continuous functions of t (see syntax changes above).
      -plot and -table options were added to felt to control the output.
   2. direct assembly into compact columns for the K, M and C matrices - this
      can represent a major savings in memory.
   3. automatic node renumbering for bandwidth/profile reduction of the
      matrices - in felt it is activated by a command line switch;
      in velvet you can do it once and for all and the way your problem
      is shown and saved will reflect the new numbering or you can implement
      it with a toggle as in felt that just does it to solve the problem
      and then reverts back to the old numbers to show you your solution
   4. renumber and summary toggles were added to the solution dialog in
      velvet to mirror felt command line options.  plot and table toggles
      in that same dialog reflect new command line options in felt that control
      the output for a transient analysis problem.
   5. static and transient mode analysis toggles in the solution dialog
      to control the problem mode (equivalent to analysis= in the problem
      description section of a FElt file).
   6. an analysis parameters dialog box to account for the new section
      in the FElt syntax.
   7. animation of transient analysis simulations as a special case solution
      mode for these types of problems.  The animation popup includes controls
      for speed, play forward/backward, stop and a time counter. 
   8. the ability to evaluate an expression wherever velvet is expecting a
      floating point number in a dialog box (i.e., forces, material properties,
      nodal coordinates) just like you can use an expression in the regular
      FElt syntax, including the variable t in dynamic forces.
   9. element mass matrix (consistent and lumped) definitions for truss, 
      beam and timoshenko elements.  Only lumped mass formulations are done
      for beam3d and cst elements.  Nothing is done for isoparametric 
      elements.
