#!/usr/bin/env python import collections import sys import inspect import pandas as pd import itertools as it class MySettings(object): def __init__(self): k = 0 def main(arg): my_settings = MySettings() try: tests(int(arg[1])) except: tests() def tests(limit=10): for comb in it.combinations_with_replacement(range(1, limit + 1), 5): knot_description, null_comb, all_comb = second_sum(*comb) if null_comb^2 >= all_comb: print "\n\nHURA!!" print comb print knot_description print "Zero cases: " + str(null_comb) print "All cases: " + str(all_comb) # for comb in it.combinations_with_replacement(range(1, limit + 1), 4): # print comb # print first_sum(*comb) class SignatureFunction(object): """ This simple class encodes twisted and untwisted signature functions of knots. Since the signature function is entirely encoded by its signature jump, the class stores only information about signature jumps in a dictionary self.data. The dictionary stores data of the signature jump as a key/values pair, where the key is the argument at which the functions jumps and value encodes the value of the jump. Remember that we treat signature functions as defined on the interval [0,1). """ def __init__(self, values=[]): # We will store data of signature jumps here. self.data = collections.defaultdict(int) # values contain initial data of singature jumps for jump_arg, jump in values: assert 0 <= jump_arg < 1, \ "Signature function is defined on the interval [0, 1)." self.data[jump_arg] = jump def value(self, arg): # Compute the value of the signature function at the point arg. # This requires summing all signature jumps that occur before arg. assert 0 <= arg < 1, \ "Signature function is defined on the interval [0, 1)." val = 0 for jump_arg, jump in self.data.items(): if jump_arg < arg: val += 2 * jump elif jump_arg == arg: val += jump return val def sum_of_absolute_values(self): return sum([abs(i) for i in self.data.values()]) def double_cover(self): new_data = [] for jump_arg, jump in self.data.items(): new_data.append((mod_one(jump_arg/2), jump)) new_data.append((mod_one(1/2 + jump_arg/2), jump)) return SignatureFunction(new_data) def __lshift__(self, shift): # Shift of the signature functions correspond to the rotations. return self.__rshift__(-shift) def __rshift__(self, shift): new_data = [] for jump_arg, jump in self.data.items(): new_data.append((mod_one(jump_arg + shift), jump)) return SignatureFunction(new_data) def __sub__(self, other): # we can perform arithmetic operations on signature functions. return self + other.__neg__() def __neg__(self): new_data = [] for jump_arg, jump in self.data.items(): new_data.append(jump_arg, -jump) return SignatureFunction(new_data) def __add__(self, other): new_signature_function = SignatureFunction() new_data = collections.defaultdict(int) for jump_arg, jump in other.data.items(): new_data[jump_arg] = jump + self.data.get(jump_arg, 0) for jump_arg, jump in self.data.items(): if jump_arg not in new_data.keys(): new_data[jump_arg] = self.data[jump_arg] new_signature_function.data = new_data return new_signature_function def __str__(self): return '\n'.join([str(jump_arg) + ": " + str(jump) for jump_arg, jump in sorted(self.data.items())]) # def __repr__(self): # return self.__str__() # Proposition 9.8. def get_blanchfield_for_pattern(k_n, theta): if theta == 0: return get_untwisted_signature_function(k_n) results = [] k = abs(k_n) ksi = 1/(2 * k + 1) # lambda_odd (theta + e) % 2 == 0: for e in range(1, k + 1): if (theta + e) % 2 != 0: results.append((e * ksi, 1 * sgn(k_n))) results.append((1 - e * ksi, -1 * sgn(k_n))) # lambda_even # print "normal" for e in range(1, theta): if (theta + e) % 2 == 0: results.append((e * ksi, 1 * sgn(k_n))) results.append((1 - e * ksi, -1 * sgn(k_n))) # print "reversed" for e in range(theta + 1, k + 1): if (theta + e) % 2 != 0: continue results.append((e * ksi, -1 * sgn(k_n))) results.append((1 - e * ksi, 1 * sgn(k_n))) return SignatureFunction(results) # # def get_sigma(t, k): # p = 2 # q = 2 * k + 1 # sigma_set = get_sigma_set(p, q) # sigma = len(sigma_set) - 2 * len([z for z in sigma_set if t < z < 1 + t]) # return sigma # # # def get_sigma_set(p, q): # sigma_set = set() # for i in range(1, p): # for j in range(1, q): # sigma_set.add(j/q + i/p) # return sigma_set # Bl_theta(K'_(2, d) = # Bl_theta(T_2, d) + Bl(K')(ksi_l^(-theta) * t) # + Bl(K')(ksi_l^theta * t) def get_cable_signature_as_theta_function(*arg): def signture_function(theta): if theta > abs(arg[-1]): print "k for pattern is " + str(arg[-1]) print "theta shouldn't be larger than this" return None cable_signature = get_blanchfield_for_pattern(arg[-1], theta) for i, k in enumerate(arg[:-1][::-1]): ksi = 1/(2 * abs(k) + 1) power = 2^i a = get_untwisted_signature_function(k) shift = theta * ksi * power b = a >> shift c = a << shift for _ in range(i): b = b.double_cover() c = c.double_cover() b += c cable_signature += b return cable_signature return signture_function def get_untwisted_signature_function(j): # Return the signature function of the T_{2,2k+1} torus knot. k = abs(j) w = ([((2 * a + 1)/(4 * k + 2), -1 * sgn(j)) for a in range(k)] + [((2 * a + 1)/(4 * k + 2), 1 * sgn(j)) for a in range(k + 1, 2 * k + 1)]) return SignatureFunction(w) def get_function_of_theta_for_sum(*arg): """ Function intended to calculate signature function for a connected sum of multiple cables with varying theta parameter values. Accept arbitrary number of arguments (number of cables in connected sum). Each argument should be given as list of integer representing k - parameters for a cable: parameters k_i (i=1,.., n-1) for satelit knots T(2, 2k_i + 1) and - the last one - k_n for a pattern knot T(2, 2k_n + 1). Returns a function described below. """ def signature_function_for_sum(*thetas): # Returns object of SignatureFunction class for a previously defined # connercted sum of len(arg) cables. # Accept len(arg) arguments: for each cable one theta parameter. # If call with no arguments, all theta parameters are set to be 0. la = len(arg) lt = len(thetas) if lt == 0: return signature_function_for_sum(*(la * [0])) if lt != la: msg = "This function takes exactly " + str(la) + \ " arguments or no argument at all (" + str(lt) + " given)." raise TypeError(msg) sf = SignatureFunction([(0, 0)]) for i, knot in enumerate(arg): sf += (get_cable_signature_as_theta_function(*knot))(thetas[i]) return sf return signature_function_for_sum def mod_one(n): """This function returns the fractional part of some number.""" return n - floor(n) # ###################### TEMPORARY TESTS ######### # def first_sum(*arg): # k_0, k_1, k_2, k_3 = arg # F = get_function_of_theta_for_sum([k_3], [-k_2], # [-k_0, -k_1, -k_3], # [k_0, k_1, k_2]) # all_combinations = (k_3 + 1) * (k_2 + 1) * (k_3 + 1) * (k_2 + 1) # null_combinations = 0 # non_trivial_zeros = 0 # for v_theta in it.product(range(k_3 + 1), range(k_2 + 1), # range(k_3 + 1), range(k_2 + 1)): # f = F(*v_theta) # if f.sum_of_absolute_values() != 0 and sum(v_theta) == 0: # print 4 * "\n" + "something wrong!!!!!!!!!!" # print inspect.stack()[0][3] # print arg # print v_theta # # if f.sum_of_absolute_values() == 0: # null_combinations += 1 # if sum(v_theta) != 0: # if len(arg) == len(set(arg)) and len(set(v_theta)) > 1: # non_trivial_zeros += 1 # # print "\nNontrivial zero" # # print inspect.stack()[0][3] # print arg # print v_theta # print # return non_trivial_zeros, null_combinations, all_combinations def get_knot_descrption(*arg): description = "" for knot in arg: if knot[0] < 0: description += "-" description += "T(" for k in knot: description += "2, " + str(abs(k)) + "; " description = description[:-2] description += ") # " return description[:-3] def get_number_of_combinations(*arg): number_of_combinations = 1 for knot in arg: number_of_combinations *= (2 * knot[-1] + 1) return number_of_combinations def second_sum(*arg): k_0, k_1, k_2, k_3, k_4 = arg knot_sum = [[k_0, k_1, k_2], [k_3, k_4], [-k_0, -k_3, -k_4], [-k_1, -k_2]] F = get_function_of_theta_for_sum(*knot_sum) knot_description = get_knot_descrption(*knot_sum) all_combinations = get_number_of_combinations(*knot_sum) null_combinations = 1 # non_trivial_zeros = 0 for v_theta in it.product(range(k_2 + 1), range(k_4 + 1), range(k_4 + 1), range(k_2 + 1)): f = F(*v_theta) assert f.sum_of_absolute_values() == 0 or sum(v_theta) != 0 if f.sum_of_absolute_values() == 0 and sum(v_theta) != 0: null_combinations += 2 # if len(arg) == len(set(arg)) and len(set(v_theta)) > 1: # non_trivial_zeros += 1 # print "\nNontrivial zero" # print inspect.stack()[0][3] # print arg # print v_theta # print return knot_description, null_combinations, all_combinations if __name__ == '__main__' and '__file__' in globals(): main(sys.argv)