Command line options

The basic syntax is

pss [options] <inputfiles>

Input polynomial systems end with the extension .poly. The following output files
are produced for myexample.poly:

myexample.lifting contains the polytopes, the lifting used, and more information. After general integers (you can read what they are in the comments) is a lattice basis in Hermite normal form. All points are represented in coordinates with respect to that basis.

After each point of the polytope, there is a real number: the value of the lifting. If it is more than 1.0, then this point is an interior point (it was lifted more so it does not interfer with mixed volume computations). Each point in the disjoint union of polytopes is identified by an integer starting from zero. This integer appears after the comment sign (#).

After the polytopes comes the list of sharp edges leaving from each point.

myexample.tgt contains the coefficients of the target polynomial. They are ordered the same as the points of the polytopes.

myexample.mixed contains the mixed cells. Each mixed cell is represented by a list of integers, each integer standing for a point in one of the polytopes. Depending on the verbosity mode, it contains more information.

myexample.starter contains the coefficient of a random polynomial system with the same structure as the target system.

myexample.u1 contains the solutions (in logarithmic coordinates) for the starter system, while myexample.u2 contains the solutions for the target system (also in logarithmic coordinates).

myexample.mac contains a maxima readable representation of the solutions.

You can use the already computed .lifting, .mixed or u1 files as input to pss. Then it will continue the computations from this point.

The main options are:

Option | What it does
-h | Prints a help screen
-v | Increases verbosity, and prints progress messages while running.
-q | Quiet
-f | Forces recomputations. Otherwise, already computed files are just checked to be actual with respect to the files they are supposed to depend from.
-M | Stops after computing the mixed volume.
-C | Stops after solving the .starter system.
-e | Computes extended mixed volume and solves in affine space.
-R | Experimental! This finds mixed volumes by a random walk. Very fast in some examples and slow in others.
--timing | Timing information

To get the complete list of options, type

man pss

Other examples

To run pss in parallel, you need to invoke MPI with a command like

 mpirun -H localhost -np 4 pss [options] <inputfiles>

To run pss in an extra terminal and wait for your keystroke befor dismissing, do

 xterm -e pss --persist [options] <inputfiles>