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"""This file contains a simple example that demonstrates the usage of the library interface"""
if __name__ == "__main__":
print("""
we will build an ordered boundary matrix of this simplicial complex consisting of a single triangle:
3
|\\
| \\
| \\
| \\ 4
5| \\
| \\
| 6 \\
| \\
|________\\
0 2 1
""")
import phat
# set the dimension of the cell that each column represents:
dimensions = [0, 0, 1, 0, 1, 1, 2]
# define a boundary matrix with the chosen internal representation
boundary_matrix = phat.boundary_matrix(representation = phat.representations.vector_vector)
# set the respective columns -- the columns entries have to be sorted
boundary_matrix.set_dims(dimensions)
boundary_matrix.set_col(0, [])
boundary_matrix.set_col(1, [])
boundary_matrix.set_col(2, [0,1])
boundary_matrix.set_col(3, [])
boundary_matrix.set_col(4, [1,3])
boundary_matrix.set_col(5, [0,3])
boundary_matrix.set_col(6, [2,4,5])
# print some information of the boundary matrix:
print()
print("The boundary matrix has %d columns:" % boundary_matrix.get_num_cols())
for col_idx in range(boundary_matrix.get_num_cols()):
s = "Column %d represents a cell of dimension %d." % (col_idx, boundary_matrix.get_dim(col_idx))
if (not boundary_matrix.is_empty(col_idx)):
s = s + " Its boundary consists of the cells " + " ".join([str(c) for c in boundary_matrix.get_col(col_idx)])
print(s)
print("Overall, the boundary matrix has %d entries." % boundary_matrix.get_num_entries())
pairs = phat.compute_persistence_pairs(boundary_matrix)
pairs.sort()
print()
print("There are %d persistence pairs: " % len(pairs))
for pair in pairs:
print("Birth: %d, Death: %d" % pair)
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