Configuration Notes

<stxxl> library

refer to <stxxl> homepage
In most cases, few adaptations in stxxl/compiler.make (name of your g++ compiler, path of stxxl) are sufficient.

emmst/compiler.make

The name of the g++ compiler (version 3.2) has to be adapted if it differs from 'g++'.
In most cases, no further modifications are necessary.
In most cases, the Makefile itself needs no adaptation.

emmst/config.h

The file 'emmst/config.h' contains constants and template parameters that are used by the program. This settings have to be adapted according to the available main memory, the number of hard disks and the properties of the graphs that will be used. It is necessary to recompile the program after each modification.

The 'internal memory for sorting' should be less than the available main memory.
The 'default page size', 'mst page size', 'external prefetch pool' and the 'external write pool' should be equal to the number of hard disks
5 times the size of the first external bucket has to be less than the available main memory.
The size of the other external buckets should be decreased when denser graphs are processed. We used 1,800,000 for m = 2 * n, 900,000 for m = 4 * n and 450,000 for m = 8 * n.
If the program aborts with the error message 'CommonPoolOfBlocks: request(): No free blocks available !', you should increase the number of internal blocks.
When the program is started, it prints a 'memory usage forecast'. This value should be less than the available main memory. The easiest way to reduce the amount of used main memory is the decreasing of the external block size. However, values less than 512 KB decelerate the program.
In most cases, no further modifications are necessary.

emmst/utils/geometricGraphGenerator.h

It could be necessary to adapt the geometric graph generator if graphs of this type were processed. There are some constants in 'emmst/utils/geometricGraphGenerator.h'.
Particularly, '_poolNoOfBlocks' should be decreased if the generator needs too much memory.

emmst/.stxxl

The file '.stxxl' contains one line per hard disk. For each disk the first two parameters are the name and the size (in MB) of the file that is used for the external storage.