5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM
Since FORTRAN IV
variable-dimensioning techniques were used in EXTERMINATOR2, the
only restriction on problem size is the available core storage.
The code examines the problem size and stores fluxes and equation
coefficients (except for scattering matrix coefficients which are
recalculated at each iteration) according to the machine core size
in one of four ways -
(1) All fluxes and equation coefficients are contained in
core and no I/O devices are used during the iterative
part of the calculation.
(2) All equation coefficients are contained in core and I/O
devices are used to store the fluxes.
(3) The fluxes are contained in core and I/O devices are used
to store the equation coefficients.
(4) Both coefficients and fluxes are used from I/O devices.
For a problem with an I*J mesh, K energy groups, M different
materials, N nuclides, and L sets of specifications of composition
locations, the core storage required for variables, when all
fluxes and coefficients are used from I/O devices, is
4*I + 24*J + 16*K + 2*M + 6*N + (2*M + N + 1)*K**2
+ 8*I*J + 14*J*K + 15*M*K + M*N + 4*N*K + 5*L + 8
words. The core storage required to be able to contain the fluxes
and coefficients in core is
4*I + 24*J + 16*K + 2*M + 6*N + (2*M + N + 1)*K**2 +
8*I*J + 4*J*K + 15*M*K + M*N + 4*N*K + 5*L + 8*I*J*K + 10.
If all cross sections are macroscopic, N is 1 above.