Orb fundamental group

Author: unhyperbolic

src/snappy/extensions/Orb/cython_src/Orb.pxi

@@ -1,4 +1,4 @@
-cdef extern from *:
+cdef extern from "SnapPea.h":
 
     ctypedef enum c_SolutionType "SolutionType":
         not_attempted
@@ -18,12 +18,17 @@ cdef extern from *:
     extern c_SolutionType find_structure(c_Triangulation *manifold, Boolean) except *
     extern Real my_volume(c_Triangulation *manifold, Boolean * ok) except *
 
+    extern int get_num_cusps(c_Triangulation *manifold) except *
+    extern int get_num_or_cusps(c_Triangulation *manifold) except *
+    extern int get_num_nonor_cusps(c_Triangulation *manifold) except *
+
 cdef extern from "kernel_prototypes.h":
     extern void remove_finite_vertices(c_Triangulation *manifold)
 
 cdef extern from "triangulation.h":
     ctypedef struct c_Triangulation "Triangulation":
         int num_tetrahedra
+        
 
 cdef extern from "unix_file_io.h":
     extern c_Triangulation *read_triangulation(char *file_name)
@@ -52,3 +57,4 @@ cdef extern from "orb_io.h":
         char *file_data,
         c_Triangulation ** trig,
         c_Diagram ** diagram)
+    

src/snappy/extensions/Orb/cython_src/Orbcore.pyx

@@ -4,6 +4,8 @@ include "Orb.pxi"
 include "../../shared/cython_src/basic_conversions.pyx"
 include "../../shared/cython_src/number_conversions.pyx"
 include "../../shared/cython_src/ui_functions.pyx"
+include "../../shared/cython_src/basic.pyx"
 include "core/basic.pyx"
 include "core/orb_triangulation.pyx"
 include "core/orbifold.pyx"
+include "core/fundamental_group.pyx"

src/snappy/extensions/Orb/cython_src/core/basic.pyx

@@ -1,6 +1,21 @@
+# Python modules
+import os
+import sys
+import re
+import time
+
+# Sage interaction
+from ..sage_helper import _within_sage, SageNotAvailable
+try:
+    from sage.groups.free_group import FreeGroup
+except ImportError:
+    pass
+
+from ..matrix import matrix
 from .. import number
 
-import os, sys, time
+# SnapPy components
+from .. import snap
 
 SolutionType = [
     'not attempted',

src/snappy/extensions/Orb/cython_src/core/fundamental_group.pyx

@@ -0,0 +1,3 @@
+ctypedef OrbTriangulation Triangulation
+
+include "../../../SnapPy/cython_src/core/fundamental_group.pyx"

src/snappy/extensions/Orb/cython_src/core/orb_triangulation.pyx

@@ -1,3 +1,5 @@
+from ..cache import SnapPyCache
+
 cdef class OrbTriangulation:
     """
 
@@ -9,10 +11,12 @@ cdef class OrbTriangulation:
 
     cdef c_Triangulation* c_triangulation
     cdef c_Diagram* c_diagram
+    cdef readonly _cache
 
     def __cinit__(self, spec=None, remove_finite_vertices=True):
         self.c_triangulation = NULL
         self.c_diagram = NULL
+        self._cache = SnapPyCache()
 
         for attr in [
                 '_to_orb_string',
@@ -162,3 +166,41 @@ cdef class OrbTriangulation:
             self.c_diagram, True)
 
         return True
+
+    def fundamental_group(
+            self,
+            simplify_presentation : bool = True,
+            fillings_may_affect_generators : bool = True,
+            minimize_number_of_generators : bool = True,
+            try_hard_to_shorten_relators : bool = True
+            ) -> FundamentalGroup:
+        if self.c_triangulation is NULL:
+            raise ValueError('The Triangulation is empty.')
+        args = (simplify_presentation, fillings_may_affect_generators,
+                minimize_number_of_generators, try_hard_to_shorten_relators)
+        try:
+            return self._cache.lookup('fundamental_group', *args)
+        except KeyError:
+            pass
+
+        return self._cache.save(FundamentalGroup(self, *args),
+                                'fundamental_group', *args)
+
+    def num_cusps(self, cusp_type='all') -> int:
+        """
+        Return the total number of cusps.  By giving the optional argument
+        'orientable' or 'nonorientable' it will only count cusps of that type.
+
+        >>> M = Triangulation('m125')
+        >>> M.num_cusps()
+        2
+        """
+        if cusp_type == 'all':
+            return get_num_cusps(self.c_triangulation)
+        elif cusp_type == 'orientable':
+            return get_num_or_cusps(self.c_triangulation)
+        elif cusp_type == 'nonorientable':
+            return get_num_nonor_cusps(self.c_triangulation)
+        else:
+            raise ValueError("Acceptable cusp types are "
+                             "['all', 'orientable', 'nonorientable'].")