.LM 10
.RM 66
.skip 2
.LITERAL
date:     June 1, 1984
#
to:       HGraph DECUS Users
#
from:     Dennis V. Jensen
          Ames Laboratory
          310 Metallurgy
          Ames, Iowa  50011     515/294-4823
#
subject:  HGraf2 - The Second HGraph DECUS Release.
.END LITERAL
.TITLE ##########HGraf2 - The Second HGraph DECUS Release.
.SKIP 1
.ap
.comment Start the text below here

The initial DECUS release of HGraph was at the Fall 1983
Symposium.  It was released to the RT, RSX, and VAX SIG tapes.
The RSX release is known to not be complete in the ASCII text.
Release one was coded entirely in DEC Fortran 66 compatible code.

This second release is being distributed at the Spring 1984 symposium.
Included in the second release is a new WRTSTR (extracted
as WRTST2.*) which will generate characters as vectors;
it is not dependent on the Visual 550 character generator.  Also, there is a
cubic spline interpolation line drawing routine (extracted as SMOOTH.*)
which is compatible with the DASHLN calling convention.

Release two is coded in FLECS.  This structured Fortran code is contained
in the .FLX files.  The FLECS generated 
Fortran 66 code is in the .FOR files.
The HGraph document is in the
HGraph.DOC file with the associated Runoff file as HGraph.RNO.
An RT-11 FLECS
translator 
FLECS.* (RE: RT SIG Fall 81 Tape) is also included for
reference.  
Refer to the VAX Fall 82 SIG Tape [VAX82B.FORDAERO.UTIL.FORDUTIL]
(or something to this effect) for a VMS FLECS translator.

PLOT3D.FOR is included as a separate file.  A FLECS version is not included
as it does not exist.  PLOT3D is known to have bugs, but will work for many
of the 3D plots you may wish to do.  Although considerable development is
occuring at the Ames Laboratory on the 2D versions of HGraph, no additional
work is currently planned for the 3D code; PLOT3D  should be treated
as unsupported.

Modifications included in this distribution correct a problem detected in
calls to subroutine XAXIS when threaded code is produced.
This problem is characterized by a
"?MON-F-Trap to 4 NNNNNN" error message being produced in response to
a call subroutine AXIS.  The solution to the problem is to
generate in-line EIS code for subroutine XAXIS.  Included in this
distribution is a version of HGRAPH.FLX with subroutine XAXIS removed,
file XAXIS.FLX.  The 
indirect command file HGRAPH.BLD will build an HGRAPH object library
that includes the SMOOTH and PLOT3D features as well as the problem
correction.

When using HGRAPH it is common to encounter the message "LINK-F-Library
list overflow".  Increase the library list
size with the /P switch when linking.  
For example:
.LITERAL
		r link
		prog/P:400=prog,sy:hgraph
.END LITERAL

A commonly occuring run-time error when using HGRAPH is "?MON-F-Trap 
to 4 NNNNNN".  This message often indicates a lack of program
stack space.  The solution is to increase the amount of
program stack space using the /B linker option.  For example:
.LITERAL
		r link
		prog/B:1200=prog,sy:hgraph
.END LITERAL
The default value of B is 1000 octal.  

In fact, you may notice that 
this problem has basically the same outward appearance as the XAXIS
problem mentioned above, the solution of which was to use inline code.
Inline code requires less stack space, so users of inline code may
not need to increase the stack.  Users of threaded code will typically
need more stack.  It is quite likely that if the stack is of sufficient
size, there is no need for XAXIS to be inline.  I have not verified this,
though.

All code included in this distribution is in the public domain and may
not be marketed for profit.  It may be altered without the explicit 
permission of the authors.  Any corrections or significant modifications 
to HGraph are of interest to the authors and may be communicated to the
address above.  The authors and their employers assume no responsibility for
the correctness or the appropriatness of the software included in this
distribution.

.comment Text ends here.
.BREAK