EFcalc - Event/Fault Tree Calculator

Answer File (*.ans)

Numerical listing of answers designed to be read by other programs but also still readable by the user. The format of the first part of the answer file is as follows:

     2                           ! Number of Event Trees
     19                          ! Number of sequences
     0.177278+00   0.81700E-03   ! Probability and uncertainty of
     0.247908-03   0.68579E-05   !    each sequence
     .                           !
     .                           !
     0.83566E-01   0.38293E-02   !
     0.31620E-02   0.14426E-10   !
     2                           ! Number of consequences
     2  0.90837E+00 0.38871E-02  ! Consequence, probability and 
     4  0.91620E-01 0.38871E-02  !   uncertainty of each consequence
     8                           ! Number of branch pts in event tree
     3 11 0.56382E+00	         ! Location of event tree branch is 
     5 12 0.58377E+00	         !  described by two integers: the 
     .                           !  sequence number and the system
     .				 !  number. 
     18  2 0.10485E+00	         ! Failure probability of that branch
     19  1 0.31620E-02	         !  is then given. (No uncert available)

(repeated for each event tree). Following the event tree information, the individual fault tree gate probabilities and their uncertainties are then given.

     tap    .166800E+00  .527214E-02 ! Each gate in the fault tree
     tap    .166800E+00  .527214E-02 !  *.equ file - its failure 
     tbp    .206600E+00  .572566E-02 !  probability and the uncertainty
     g0002  .76900E+00   .59605E-02  !
     g0003  .76180E+00   .60242E-02  !

Of course, the program should already know the number of sequences, the number of consequences and the number of branch points (#seq -1). These are added to make the file more readable to the human and for possible use in other programs.

Uncertainties represent stochastic uncertainties only. They do not reflect the uncertainties in the input probabilities. If the direct solve method is used, these uncertainties will be zero.

Note that the number of consequences could be 0. This is from a master event tree that listed other event trees as its consequences.

When called from the command line, EFcalc will automatically produce the *.ans file. When called from inside other Java programs, the *.ans file is not written to disk unless the user specifically requests so.

Oak Ridge National Laboratory, 2004

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