amitjamadagni

r"""
Link class
"""
#*****************************************************************************
#  Copyright (C) 2014
#
#  Distributed under the terms of the GNU General Public License (GPL)
#                  http://www.gnu.org/licenses/
#*****************************************************************************

amitjamadagni

    def seifert_circles(self, oriented_gauss_code):
        self.oriented_gauss_code = oriented_gauss_code
        x = self.PD_code_ogc(self.oriented_gauss_code)
        s = [[None for i in range(4)] for i in range(len(x))]
        for i in range(len(x)):
            s[i][0] = 'entering'
            s[i][2] = 'leaving'
            if self.oriented_gauss_code[1][i] == '-':
                s[i][1] = 'leaving'
                s[i][3] = 'entering'

amitjamadagni

#whatever is the crossing one should give the sign for that first
    #the order of the sign is as per the ordering of the crossings as in the gauss code
    #so for example if the gauss code is 1 -3 2 -1 3 -2 then the order of the sign of the crossings is
    #sign of crossing 1 then 3 then at 2 and so on and so forth.
    def PD_code_ogc(self, oriented_gauss_code):
        self.oriented_gauss_code = oriented_gauss_code
        gc = self.oriented_gauss_code[0]
        gc_sign = self.oriented_gauss_code[1]
        l = [0 for i in range(len(gc))]
        for i in range(len(gc)):

amitjamadagni

def final_seifert_circles(self):
        sc = self.seifert_circles()
        regions = self.regions()
        y = self.PD_code()
        while True:
            x = deepcopy(y)
            q1 = deepcopy(regions)
            q = [[[],[]] for i in range(len(regions))]
            for i in range(len(regions)):
                for j in range(len(regions[i])):

amitjamadagni

def final_seifert_circles(self):
        sc = self.seifert_circles()
        regions = self.regions()
        y = self.PD_code()
        while True:
            q = [[[],[]] for i in range(len(regions))]
            for i in range(len(regions)):
                for j in range(len(regions[i])):
                    if regions[i][j] < 0:
                        q[i][0].append(regions[i][j])

amitjamadagni

sage: L = link.Link(oriented_gauss_code = [[-1, +2, -3, 4, +5, +1, -2, +6, +7, 3, -4, -7, -6,-5],['-','-','-','-','+','-','+']])
sage: L.regions()
[[4, -11],
 [2, -7],
 [6, -1],
 [13, 9],
 [-4, -10, -12],
 [-8, -2, -6, -14],
 [10, -3, 8, -13],
 [14, -5, 12, -9],

amitjamadagni

def remove_regions(self):
        y = self.PD_code()
        x = deepcopy(y)
        sc = self.seifert_circles()
        regions = self.regions()
        q1 = deepcopy(regions)
        #splitting into positive and negative for each region
        q = [[[],[]] for i in range(len(regions))]
        for i in range(len(regions)):

amitjamadagni

def add(self):
     y = self.subtract()
     <some other code>
     if do something:
           y = None
     else:
           return y

amitjamadagni

def final(self):
        x = self.PD_code()
        L = Link(PD_code = x)
        y = L.remove_regions()
        while True:
            if y == 'No more regions':
                break
            else:
                L = Link(PD_code = y)
                y = L.remove_regions()

amitjamadagni

def remove_regions(self):
        #self.oriented_gauss_code = oriented_gauss_code
        z = self.PD_code()
        x = deepcopy(z)
        #x = self.PD_code_ogc(self.oriented_gauss_code)
        #sc = self.seifert_circles(self.oriented_gauss_code)
        sc = self.seifert_circles()
        #print sc
        #regions = self.regions(self.oriented_gauss_code)
        regions = self.regions()