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Fix mypy in #3149 (#3988)
* Fix mypy in #3149 
* Fix pre-commit
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poyea committed Nov 29, 2020
1 parent ba6310b commit 06dad4f9d8624d9b9a4be56fef47a657f6ce6b82
Showing with 67 additions and 62 deletions.
  1. +12 −9 blockchain/chinese_remainder_theorem.py
  2. +25 −25 blockchain/diophantine_equation.py
  3. +30 −28 blockchain/modular_division.py
@@ -1,18 +1,21 @@
# Chinese Remainder Theorem:
# GCD ( Greatest Common Divisor ) or HCF ( Highest Common Factor )
"""
Chinese Remainder Theorem:
GCD ( Greatest Common Divisor ) or HCF ( Highest Common Factor )
# If GCD(a,b) = 1, then for any remainder ra modulo a and any remainder rb modulo b
# there exists integer n, such that n = ra (mod a) and n = ra(mod b). If n1 and n2 are
# two such integers, then n1=n2(mod ab)
If GCD(a,b) = 1, then for any remainder ra modulo a and any remainder rb modulo b
there exists integer n, such that n = ra (mod a) and n = ra(mod b). If n1 and n2 are
two such integers, then n1=n2(mod ab)
# Algorithm :
Algorithm :
# 1. Use extended euclid algorithm to find x,y such that a*x + b*y = 1
# 2. Take n = ra*by + rb*ax
1. Use extended euclid algorithm to find x,y such that a*x + b*y = 1
2. Take n = ra*by + rb*ax
"""
from typing import Tuple


# Extended Euclid
def extended_euclid(a: int, b: int) -> (int, int):
def extended_euclid(a: int, b: int) -> Tuple[int, int]:
"""
>>> extended_euclid(10, 6)
(-1, 2)
@@ -1,12 +1,14 @@
# Diophantine Equation : Given integers a,b,c ( at least one of a and b != 0), the
# diophantine equation a*x + b*y = c has a solution (where x and y are integers)
# iff gcd(a,b) divides c.
from typing import Tuple

# GCD ( Greatest Common Divisor ) or HCF ( Highest Common Factor )


def diophantine(a: int, b: int, c: int) -> (int, int):
def diophantine(a: int, b: int, c: int) -> Tuple[float, float]:
"""
Diophantine Equation : Given integers a,b,c ( at least one of a and b != 0), the
diophantine equation a*x + b*y = c has a solution (where x and y are integers)
iff gcd(a,b) divides c.
GCD ( Greatest Common Divisor ) or HCF ( Highest Common Factor )
>>> diophantine(10,6,14)
(-7.0, 14.0)
@@ -26,19 +28,19 @@ def diophantine(a: int, b: int, c: int) -> (int, int):
return (r * x, r * y)


# Lemma : if n|ab and gcd(a,n) = 1, then n|b.

# Finding All solutions of Diophantine Equations:
def diophantine_all_soln(a: int, b: int, c: int, n: int = 2) -> None:
"""
Lemma : if n|ab and gcd(a,n) = 1, then n|b.
# Theorem : Let gcd(a,b) = d, a = d*p, b = d*q. If (x0,y0) is a solution of Diophantine
# Equation a*x + b*y = c. a*x0 + b*y0 = c, then all the solutions have the form
# a(x0 + t*q) + b(y0 - t*p) = c, where t is an arbitrary integer.
Finding All solutions of Diophantine Equations:
# n is the number of solution you want, n = 2 by default
Theorem : Let gcd(a,b) = d, a = d*p, b = d*q. If (x0,y0) is a solution of
Diophantine Equation a*x + b*y = c. a*x0 + b*y0 = c, then all the
solutions have the form a(x0 + t*q) + b(y0 - t*p) = c,
where t is an arbitrary integer.
n is the number of solution you want, n = 2 by default
def diophantine_all_soln(a: int, b: int, c: int, n: int = 2) -> None:
"""
>>> diophantine_all_soln(10, 6, 14)
-7.0 14.0
-4.0 9.0
@@ -67,13 +69,12 @@ def diophantine_all_soln(a: int, b: int, c: int, n: int = 2) -> None:
print(x, y)


# Euclid's Lemma : d divides a and b, if and only if d divides a-b and b

# Euclid's Algorithm


def greatest_common_divisor(a: int, b: int) -> int:
"""
Euclid's Lemma : d divides a and b, if and only if d divides a-b and b
Euclid's Algorithm
>>> greatest_common_divisor(7,5)
1
@@ -94,12 +95,11 @@ def greatest_common_divisor(a: int, b: int) -> int:
return b


# Extended Euclid's Algorithm : If d divides a and b and d = a*x + b*y for integers
# x and y, then d = gcd(a,b)


def extended_gcd(a: int, b: int) -> (int, int, int):
def extended_gcd(a: int, b: int) -> Tuple[int, int, int]:
"""
Extended Euclid's Algorithm : If d divides a and b and d = a*x + b*y for integers
x and y, then d = gcd(a,b)
>>> extended_gcd(10, 6)
(2, -1, 2)
@@ -1,21 +1,23 @@
# Modular Division :
# An efficient algorithm for dividing b by a modulo n.
from typing import Tuple

# GCD ( Greatest Common Divisor ) or HCF ( Highest Common Factor )

# Given three integers a, b, and n, such that gcd(a,n)=1 and n>1, the algorithm should
# return an integer x such that 0≤x≤n−1, and b/a=x(modn) (that is, b=ax(modn)).
def modular_division(a: int, b: int, n: int) -> int:
"""
Modular Division :
An efficient algorithm for dividing b by a modulo n.
# Theorem:
# a has a multiplicative inverse modulo n iff gcd(a,n) = 1
GCD ( Greatest Common Divisor ) or HCF ( Highest Common Factor )
Given three integers a, b, and n, such that gcd(a,n)=1 and n>1, the algorithm should
return an integer x such that 0≤x≤n−1, and b/a=x(modn) (that is, b=ax(modn)).
# This find x = b*a^(-1) mod n
# Uses ExtendedEuclid to find the inverse of a
Theorem:
a has a multiplicative inverse modulo n iff gcd(a,n) = 1
def modular_division(a: int, b: int, n: int) -> int:
"""
This find x = b*a^(-1) mod n
Uses ExtendedEuclid to find the inverse of a
>>> modular_division(4,8,5)
2
@@ -32,9 +34,10 @@ def modular_division(a: int, b: int, n: int) -> int:
return x


# This function find the inverses of a i.e., a^(-1)
def invert_modulo(a: int, n: int) -> int:
"""
This function find the inverses of a i.e., a^(-1)
>>> invert_modulo(2, 5)
3
@@ -50,9 +53,11 @@ def invert_modulo(a: int, n: int) -> int:

# ------------------ Finding Modular division using invert_modulo -------------------

# This function used the above inversion of a to find x = (b*a^(-1))mod n

def modular_division2(a: int, b: int, n: int) -> int:
"""
This function used the above inversion of a to find x = (b*a^(-1))mod n
>>> modular_division2(4,8,5)
2
@@ -68,17 +73,15 @@ def modular_division2(a: int, b: int, n: int) -> int:
return x


# Extended Euclid's Algorithm : If d divides a and b and d = a*x + b*y for integers x
# and y, then d = gcd(a,b)


def extended_gcd(a: int, b: int) -> (int, int, int):
def extended_gcd(a: int, b: int) -> Tuple[int, int, int]:
"""
>>> extended_gcd(10, 6)
(2, -1, 2)
Extended Euclid's Algorithm : If d divides a and b and d = a*x + b*y for integers x
and y, then d = gcd(a,b)
>>> extended_gcd(10, 6)
(2, -1, 2)
>>> extended_gcd(7, 5)
(1, -2, 3)
>>> extended_gcd(7, 5)
(1, -2, 3)
** extended_gcd function is used when d = gcd(a,b) is required in output
@@ -98,9 +101,9 @@ def extended_gcd(a: int, b: int) -> (int, int, int):
return (d, x, y)


# Extended Euclid
def extended_euclid(a: int, b: int) -> (int, int):
def extended_euclid(a: int, b: int) -> Tuple[int, int]:
"""
Extended Euclid
>>> extended_euclid(10, 6)
(-1, 2)
@@ -115,12 +118,11 @@ def extended_euclid(a: int, b: int) -> (int, int):
return (y, x - k * y)


# Euclid's Lemma : d divides a and b, if and only if d divides a-b and b
# Euclid's Algorithm


def greatest_common_divisor(a: int, b: int) -> int:
"""
Euclid's Lemma : d divides a and b, if and only if d divides a-b and b
Euclid's Algorithm
>>> greatest_common_divisor(7,5)
1

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