xref: /libCEED/examples/petsc/README.md (revision ccb3a2268a527edcea38aec159bab1ffa972162e)
1288c0443SJeremy L Thompson## libCEED + PETSc Examples
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3*ccb3a226Sjeremylt### CEED bakeoff problems with raw mesh management - bpsraw
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5*ccb3a226SjeremyltThis code solves the CEED bakeoff problems on a structured grid generated and referenced using only low-level communication primitives.
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7cb32e2e7SValeria BarraTo build, run `make bpsraw`
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9cb32e2e7SValeria BarraTo run, `./bpsraw -ceed [ceed-resource] -problem bp[1-6] -degree [degree]`
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11819eb1b3SjeremyltIn addition to the common arguments, the following arguments may be set:
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13819eb1b3Sjeremylt- `-local`             - Target number of locally owned DoFs per process
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15cb32e2e7SValeria Barra### CEED bakeoff problems with DMPlex - bps
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17819eb1b3SjeremyltThis code solves the CEED bakeoff problems on a unstructured grid using DMPlex.
18819eb1b3SjeremyltThis example requires a PETSc version later than 3.11.3.
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20cb32e2e7SValeria BarraTo build, run `make bps`
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22cb32e2e7SValeria BarraTo run, `./bps -ceed [ceed-resource] -problem bp[1-6] -degree [degree]`
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24819eb1b3SjeremyltIn addition to the common arguments, the following arguments may be set:
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26819eb1b3Sjeremylt- `-mesh`              - Read mesh from file
27819eb1b3Sjeremylt- `-cells`             - Number of cells per dimension
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29565a3730SJed Brown#### Running a suite
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31*ccb3a226SjeremyltSome run-time arguments can be passed lists, which allows a single `mpiexec` invocation to run many experiments.
32*ccb3a226SjeremyltFor example
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34565a3730SJed Brown    mpiexec -n 64 ./bps -problem bp1,bp2,bp3,bp4 -degree 2,3,5,7                \
35565a3730SJed Brown        -ceed /cpu/self/opt/serial,/cpu/self/xsmm/serial,/cpu/self/xsmm/blocked \
36565a3730SJed Brown        -local_nodes 600,20000 | tee bps.log
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38*ccb3a226Sjeremyltwhich will sample from the `4*4*3=48` specified combinations, each of which will run a problem-size sweep of 600, 1200, 2400, 4800, 9600, 192000 FEM nodes per MPI rank.
39*ccb3a226SjeremyltThe resulting log file can be read by the Python plotting scripts in `benchmarks/`.
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416c5df90dSjeremylt### CEED bakeoff problems with DMPlex and PCMG - multigrid
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43*ccb3a226SjeremyltThis code solves the CEED bakeoff problems on a unstructured grid using DMPlex with p-multigrid implemented in PCMG.
44*ccb3a226SjeremyltThis example requires a PETSc version later than 3.11.3.
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46cb32e2e7SValeria BarraTo build, run `make multigrid`
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48cb32e2e7SValeria BarraTo run, `./multigrid -ceed [ceed-resource] -problem bp[1-6] -degree [degree]`
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506c5df90dSjeremyltIn addition to the common arguments, the following arguments may be set:
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526c5df90dSjeremylt- `-mesh`              - Read mesh from file
536c5df90dSjeremylt- `-cells`             - Number of cells per dimension
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55288c0443SJeremy L Thompson### Command line arguments
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57cb32e2e7SValeria BarraThe following arguments can be specified for all of the above examples:
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59819eb1b3Sjeremylt- `-ceed`              - CEED resource specifier
60819eb1b3Sjeremylt- `-problem`           - CEED benchmark problem to solve
616c5df90dSjeremylt- `-degree`            - Polynomial degree of tensor product basis
62819eb1b3Sjeremylt- `-qextra`            - Number of extra quadrature points
63819eb1b3Sjeremylt- `-test`              - Testing mode (do not print unless error is large)
64819eb1b3Sjeremylt- `-benchmark`         - Benchmarking mode (prints benchmark statistics)
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6632d2ee49SValeria Barra### libCEED example to compute surface area using DMPlex - area
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6832d2ee49SValeria BarraThis example uses the mass matrix to compute the surface area of a cube or a discrete cubed-sphere, defined via DMPlex.
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70cb32e2e7SValeria BarraTo build, run `make area`
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7232d2ee49SValeria BarraTo run, `./area -problem cube -ceed [ceed-resource] -petscspace_degree [degree]`
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7432d2ee49SValeria Barraor
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7632d2ee49SValeria Barra`./area -problem sphere -ceed [ceed-resource] -petscspace_degree [degree]`
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7832d2ee49SValeria Barra#### Command line arguments
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8032d2ee49SValeria BarraThe following arguments can be specified for the area example:
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82cb32e2e7SValeria Barra- `-ceed`              - CEED resource specifier
8332d2ee49SValeria Barra- `-problem`           - Problem to solve, either 'cube' or 'sphere'
84cb32e2e7SValeria Barra- `-petscspace_degree` - Polynomial degree of tensor product basis
85cb32e2e7SValeria Barra- `-qextra`            - Number of extra quadrature points
86cb32e2e7SValeria Barra- `-test`              - Testing mode (do not print unless error is large)
87cb32e2e7SValeria Barra- `-mesh`              - Read mesh from file
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