Symbolic versus Professional versions of
COMREL & SYSREL
Frequently there is the question whether to obtain
the Symbolic or the Pro versions of COMREL / SYSREL.
The standard editions of COMREL / SYSREL use a built-in very fast Symbolic Processor to compute the state function(s).
The professional (Pro) editions of COMREL / SYSREL allow to develop your own reliability processors but require a 32-Bit Fortran compiler.
The object libraries for the Professional versions are made for Compaq
Visual Fortran 6.x or Intel Visual Fortran 9.x/10.x.
In the Symbolic version the failure
functions (state functions, limit states) are simply typed in a window
in standard math-notation
(similar as e.g. in MathCad) and the functions are then parsed and evaluated by the program.
The Pro versions covers the
(quite rare) cases where the failure functions are too complex or lengthy for the Symbolic Processor
or the cases where large external program libraries need to be linked to evaluate
the failure functions.
In the Pro version the failure functions have to be provided
as a Fortran subroutine (called LIMIT) which is compiled
and linked with the object modules (in form of static object libraries)
of COMREL or SYSREL.
The definition of subroutine LIMIT can be done in a built in editor
or by any editor of your choice.
Besides some knowledge of Fortran the Pro-version also requires
that a Fortran compiler
(Intel Visual Fortran 9.x/10.x or Compaq Visual Fortran 6.x) is installed
on the PC running the Pro version.
The definition of the input (Stochastic Model,
Computation Options and so on)
is equal for both versions and supported
by a Windows based GUI .
If you are a new user we recommend to start with
the Symbolic versions unless you already have some experience in Fortran programming.
The reason is that the Symbolic versions are stand-alone programs.
In other words: You do not have to fight with compiler installation/version.
Obviously there are also more possibilities to produce bugs with Fortran
as compared to the straightforward way of defining the failure functions
in the Symbolic versions.
Q:
How much does it cost to migrate from Symbolic to Pro version(s) ?
A:
See our homepage: News Section -> Price List -> Other Products and Costs -> Migration Fee.
In fact, this fee just covers our handling cost (new Manual etc.), so you do not have to pay twice !
Q:
What happens to my existing model files (input) if I migrate from Symbolic to Pro ?
A:
As stated above the input for both editions is equal.
You can read a model file created in Symbolic into the Pro versions without loss of data.
The only task is to re-write the failure functions in form of a Fortran subroutine
(with fixed name Subroutine Limit and a fixed interface). The Pro version comes with many examples
and a detailed Technical Reference covering all aspects of programming this subroutine.
November 2008
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