author Dmitriy Morozov <dmitriy@mrzv.org>
Tue, 26 Jan 2010 11:00:51 -0800
changeset 191 2d8fba6d1d58
parent 181 examples/lsfiltration.py@1ee6edc17cb6
permissions -rwxr-xr-x
Moved lsfiltration.py into examples/pl-functions + added lscubes.py example (cubical lower-star filtration)

#!/usr/bin/env python

from    dionysus        import Simplex, Filtration, StaticPersistence, vertex_cmp
from    sys             import argv, exit

def max_vertex(s, vertices):
    return max((vertices[v] for v in s.vertices))

def max_vertex_cmp(s1, s2, vertices):
    m1 = max_vertex(s1, vertices)
    m2 = max_vertex(s2, vertices)
    return cmp(m1, m2) or cmp(s1.dimension(), s2.dimension())

def lsf(values_filename, simplices_filename):
    # Read vertices
    vertices = []
    with open(values_filename) as f:
        for line in f:
            if line.startswith('#'): continue

    # Read simplices
    fltr = Filtration()
    with open(simplices_filename) as f:
        for line in f:
            if line.startswith('#'): continue
            fltr.append(Simplex(map(int, line.split())))
    fltr.sort(lambda x,y: max_vertex_cmp(x,y,vertices))

    # Compute persistence
    p = StaticPersistence(fltr)
    # Output the persistence diagram
    smap = p.make_simplex_map(fltr)
    for i in p:
        if not i.sign(): continue

        b = smap[i]
        d = smap[i.pair()]

        if i.unpaired():
            print b.dimension(), max_vertex(b, vertices), "inf"

        print b.dimension(), max_vertex(b, vertices), max_vertex(d, vertices)

if __name__ == '__main__':
    if len(argv) < 3:
        print "Usage: %s VERTICES SIMPLICES" % argv[0]
        print "Computes persistence of the lower star filtration of the simplicial "
        print "complex explicitly listed out in SIMPLICES with vertex values given in VERTICES."

    values = argv[1]
    simplices = argv[2]

    lsf(values, simplices)