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MPI I/O

The mchf program implements parallel IO for the largest input data files, Figure  6.20.

Figure 6.20: The angular data are stored in files, which are processed in parallel. Files with negligible IO requirements are read by node 0, which broadcasts the data to other nodes.
\begin{figure}\centerline{ \psfig{file=tex/fig/mpi_io.eps}}\end{figure}

The IO files used by mpi_mchf can be divided into two categories based on their use:

  1. Small input data files (cfg.inp, cfg.h, wfn.inp. There is a single copy of each file. Each node process the file and broadcasts the data to the other nodes. Those files are small and incurs only a negligible communication overhead. In addition, the output files wfn.out, summry, LSn.l have a single copy, which is written by processor 0.

    1. wfn.inp initial estimates for the wave function
    2. wfn.out computed radial functions.
    3. cfg.inp configuration list
    4. cfg.h file containing information for the memory allocation.
    5. summry summary of wave function properties
    6. LSn.l eigenvectors for each LS term.

  2. Node dependent large data files, with a copy per node They contain the integral coefficient and pointer data. Depending on how extensive is the computational model, c.lst.nnn may exceed 1 GB, the pointer data files ico.lst.nnn, ih.lst.nnn, yint.lst.nnn may reach hundreds of MB, and they need to be processed in parallel. Each file has a name comprised by a basename which is the same as the serial version. However, the filename appends the node ID. Those files are needed only for the mchf calculation. They are Z independent and can be reused when the configuration lists have not changed.
    1. c.lst.000 pointer and coefficient data for each element of the Hamiltonian
    2. ico.lst.000 column indexes per element
    3. ih.lst.000 row index
    4. yint.lst.000 integral data

    Details about the format and each entry are given in chapter  14.15.


next up previous contents
Next: BP_ANG Up: MPI version Previous: Introduction   Contents
2001-10-11