提交: 698f6818f630ab65f89ba3649a0e205b4f3432f3 - GaloisField (hg)

A small kernel of code for playing with Galois fields of arbitrary characteristic

Commit MetaInfo

• 修订版: 698f6818f630ab65f89ba3649a0e205b4f3432f3 (tree)
• 时间: 2020-02-20 13:27:56
• 作者: Eric Hopper <hopper@omni...>
• Commiter: Eric Hopper

Log Message

No more fumbling with the multiplicative inverse in presentations.

更改概述

• modified: numtheory_utils.py

差异

diff -r 3e43d3f153fe -r 698f6818f630 numtheory_utils.py
--- a/numtheory_utils.py	Sun Feb 16 01:06:20 2020 -0800
+++ b/numtheory_utils.py	Wed Feb 19 20:27:56 2020 -0800
@@ -54,3 +54,15 @@
             result = op(a, b)
             print(f' {result:{width}} |', end='')
         print()
+
+
+def mult_inverses(a, b):
+    am, bm, g = extended_gcd(a, b)
+    if g == 0:
+        raise ValueError(f"{a} and {b} are not relatively prime.")
+    if am < 0:
+        am = b + am
+    if bm < 0:
+        bm = a + bm
+    return f"{a} * {am} % {b} == {a * am % b}"\
+        f"\n{b} * {bm} % {a} == {b * bm % a}"