SPEC OMP2012 Benchmark Description File
R. Van der Wijngaart
Benchmark Program General Category
Computational Fluid Dynamics
BT is a simulated CFD application that uses an implicit algorithm to
solve 3-dimensional (3-D) compressible Navier-Stokes equations. The
finite differences solution to the problem is based on an Alternating
Direction Implicit (ADI) approximate factorization that decouples the
x, y and z dimensions. The resulting systems are Block-Tridiagonal of
5x5 blocks and are solved sequentially along each dimension.
There are two approaches to control the memory and run-time requirements
of the benchmark:
For a fixed mesh size, run-time varies linearly with the number of time
steps taken. Currently, input decks are available for several different
pairs of mesh cubic sizes and the number of time steps taken.
change in mesh size,
change in number of time steps taken.
For the SPEC benchmark, the reference data set uses a grid of
408x408x408 with 130 iterations and a time step of 0.00002.
The train data set uses a grid of 102x102x102 with 200 iterations and
a time step of 0.0003. The test data set uses a grid of
64x64x64 with 200 iterations and a time step of 0.0008.
The program is capable of automatically verifying whether a given run conforms
to the specification of the benchmark by using internally stored reference
However, these reference solutions are available only for a
fixed number of mesh size/time steps pairs. If the input data does not
correspond to any of the internally stored reference solutions, the verification
test is not performed. Otherwise, the output indicates whether or not the
run was successfull in meeting the requirements of the verifications tests.
To conform to the specification of the benchmark, a run should successfully
pass all three verification tests. Failure in any one or more tests indicates
non-conformance with the specifications.
For SPEC, the solution is output for comparison to a set of
Known portability issues
H. Jin, M.Frumkin and J.Yan, "The OpenMP Implementation of
NAS Parallel Benchmarks and Its Performance",
Rept. No: NAS Technical Report NAS-99-011 October 1999
Last Updated: 15 July 2010