Merge pull request #51 from jakewilliami/dev

Dev

Project.toml

@@ -5,12 +5,10 @@ version = "0.2.0"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
-Mods = "7475f97c-0381-53b1-977b-4c60186c8d62"
 Polynomials = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 Primes = "27ebfcd6-29c5-5fa9-bf4b-fb8fc14df3ae"
 
 [compat]
-Mods = "1.2.4"
 Polynomials = "1.1.9"
 Primes = "0.5"
 julia = "1"

src/CodingTheory.jl

@@ -6,25 +6,37 @@
 
 module CodingTheory
 
+using Primes: isprime, primes
+using LinearAlgebra: I
+using Polynomials
+
+include("utils.jl")
+
+# Abstract types
 export FinitePolynomial, AbstractCode, Alphabet, Messages, no_round
-export Alphabet, Messages, rate, sphere_covering_bound, sphere_packing_bound,
+
+# RREF
+export rref, rref!
+
+# Messages, Distance, and Primes
+export rate, sphere_covering_bound, sphere_packing_bound,
         construct_ham_matrix, isperfect, ishammingperfect, isgolayperfect,
         get_codewords_greedy, get_codewords_random, get_all_words,
         get_codewords
-export FinitePolynomial, list_polys, multiplication_table, list_span, islinear,
-        isirreducible
 export hamming_distance, hamming_ball, code_distance, t_error_detecting,
         t_error_correcting, find_error_detection_max, find_error_correction_max
+export isprimepower
+
+# Algebra
+export FinitePolynomial, list_polys, multiplication_table, list_span, islinear, isirreducible, normal_form!, normal_form, equivalent_code!, equivalent_code, generator!, generator, parity_check, syndrome, isincode
+
+# Levenshtein
 export levenshtein, levenshtein!
-export normal_form!, normal_form, equivalent_code!, equivalent_code, generator!,
-        generator, parity_check, syndrome, isincode
-export rref, rref!
 
-include(joinpath(dirname(@__FILE__), "abstract_types.jl"))
-include(joinpath(dirname(@__FILE__), "messages.jl"))
-include(joinpath(dirname(@__FILE__), "distance.jl"))
-include(joinpath(dirname(@__FILE__), "fields.jl"))
-include(joinpath(dirname(@__FILE__), "algebra.jl"))
-include(joinpath(dirname(@__FILE__), "rref.jl"))
+include("abstract_types.jl")
+include("rref.jl")
+include("messages.jl") # implicitly exports distance.jl and primes.jl
+include("algebra.jl")
+include("levenshtein.jl")
 
 end # end module

src/algebra.jl

@@ -3,11 +3,212 @@
     exec julia --project="$(realpath $(dirname $(dirname $0)))" --color=yes --startup-file=no -e "include(popfirst!(ARGS))" \
     "${BASH_SOURCE[0]}" "$@"
     =#
-
-include(joinpath(dirname(@__FILE__), "utils.jl"))
-include(joinpath(dirname(@__FILE__), "rref.jl"))
 
-using LinearAlgebra: I
+"""
+	struct FinitePolynomial <: FiniteField
+		
+Has parameters `p`, which is an abstract polynomial, and `n` which is the modulus of the field under which the molynomial is defined.
+
+---
+
+	FinitePolynomial(p::AbstractPolynomial, n::Integer)
+
+A constructor method for `FinitePolynomial`.  Takes in a polynomial `p` and a number `n`, and constructs a polynomial under modulo n.
+"""
+struct FinitePolynomial <: FiniteField
+	p::AbstractPolynomial
+	n::Integer
+
+	function FinitePolynomial(p::AbstractPolynomial, n::Integer)
+		p = Polynomial(mod.(p.coeffs, n))
+		new(p, n)
+	end
+end
+
+"""
+	mod(p::Polynomial, n::Integer) -> Polynomial
+	
+Uses the FinitePolynomial constructor to return a polynomial `p` under modulus `n`.
+
+Parameters:
+  - p::Polynomial: The input polynomial.
+  - n::Integer: The modulus of the field.
+  
+Returns
+  - Polynomial: A polynomial modulo n.
+"""
+Base.mod(p::Polynomial, n::Integer) = FinitePolynomial(p, n).p
+
+"""
+	Polynomial(A::Union{Tuple, AbstractArray}, n::Integer) -> Polynomial
+	
+Constructs a polynomial under modulo `n`.
+
+Parameters:
+  - A::Union{Tuple, AbstractArrau}: The polynomial coefficients.
+  - n::Integer: The modulus of the field.
+  
+Returns
+  - Polynomial: A polynomial modulo n.
+"""
+Polynomial(A::Union{Tuple, AbstractArray}, n::Integer) = mod(Polynomial(A), n)
+
+"""
+	list_polys(n::Integer, m::Integer) -> Array
+	
+Lists all polynomials of degree less than to `n` under modulo `m`.
+
+Parameters:
+  - n::Integer: Highest degree of polynomial.
+  - m::Integer: The modulus of the field.
+  
+Returns:
+  - Array: An array of polynomials of degree less than n, under modulo m.
+"""
+function list_polys(n::Integer, m::Integer)
+	return collect(Polynomial(collect(t)) for t in Iterators.product([0:(m-1) for i in 1:n]...))
+end
+
+"""
+	multiplication_table(degree::Integer, modulo::Integer) -> Matrix
+	
+Returns a table (matrix) of the multiplication of all combinations of polynomials for degree less than `degree`, under modulo `modulo`.
+
+Parameters:
+  - degree::Integer: Highest degree of polynomial.
+  - modulo::Integer: The modulus of the field.
+  
+Returns:
+  - Matrix: A multiplication table of all polynomials with degree less than n, under modulus.
+"""
+function multiplication_table(degree::Integer, modulo::Integer)
+	polys = list_polys(degree, modulo)
+	number_of_polys = length(polys)
+	poly_matrix = Matrix{Polynomial}(undef, number_of_polys, number_of_polys)
+
+	for i in 1:number_of_polys, j in 1:number_of_polys
+		poly_matrix[i,j] = mod(polys[i]*polys[j], modulo)
+	end
+
+	return poly_matrix
+end
+
+"""
+	list_span(u̲::Vector, v̲::Vector, modulo::Integer) -> Array
+
+Given two vectors `u̲` and `v̲`, prints all linear combinations of those vectors, modulo `modulo`.  NB: this function can take in another vector, but is not yet generalised to more than three.
+
+Parameters:
+  - u̲::Vector: One vector.
+  - v̲::Vector: Another vector.
+  - modulo::Integer: The modulus of the field.
+  
+Returns:
+  - Array: All vectors in the span of u̲ and v̲, under modulo.
+"""
+function list_span(u̲::Vector, v̲::Vector, modulo::Integer)::Array{Array{Int, 1}}
+	span = Vector[]
+
+	for λ in 0:modulo-1, γ in 0:modulo-1
+		w̲ = mod.(λ*u̲ + γ*v̲, modulo)
+		if w̲ ∉ span
+			push!(span, w̲)
+		end
+	end
+
+	return span
+end
+
+function list_span(u̲::Vector, v̲::Vector, t̲::Vector, modulo::Integer)::Array{Array{Int, 1}}
+	span = Vector[]
+
+	for λ in 0:modulo-1, γ in 0:modulo-1, α in 0:modulo-1
+		w̲ = mod.(λ*u̲ + γ*v̲ + α*t̲, modulo)
+		if w̲ ∉ span
+			push!(span, w̲)
+		end
+	end
+
+	return span
+end
+
+"""
+	islinear(C::Vector, modulo::Integer; verbose::Bool=false) -> Bool
+	
+Determines whether a code `C` is a linear code (i.e., if it is closed under addition, scalar multiplication, and has the zero vector in it).
+
+Parameters:
+  - C::Vector: A code, typically consisting of multiple vectors or strings.
+  - modulo::Integer: The modulus of the field under which you are working.
+  - verbose::Bool (kwarg): print the point at which C fails, if it does.
+  
+Returns:
+  - Bool: Whether or not the code `C` is linear (true or false).
+"""
+function islinear(C::Vector, modulo::Integer; verbose::Bool=false)
+	allequal_length(C) || return false # not all codes are of the same length
+	block_length = length(C[1])
+	𝟎 = fill(0, block_length)
+
+	if 𝟎 ∉ C
+		if verbose
+			println("The zero vector 0̲ is not in C.\n")
+		end
+		return false # the zero vector is not in the code
+	end
+
+	for c̲ ∈ C
+		for λ in 0:modulo-1
+			if mod.(λ*c̲, modulo) ∉ C
+				if verbose
+					println(λ, " ⋅ ", c̲, " = ", mod.(λ*c̲, modulo), " ∉ C\n")
+				end
+				return false # this code isn't closed under scalar multiplication
+			end
+		end
+
+		for c̲ ∈ C, c̲′ ∈ C
+			if c̲ ≠ c̲′
+				if mod.(c̲ + c̲′, modulo) ∉ C
+					if verbose
+						println(c̲, " + ", c̲′, " = ", mod.(c̲ + c̲′, modulo), " ∉ C\n")
+					end
+					return false # this code isn't closed under addition
+				end
+			end
+		end
+	end
+
+	if verbose
+		println()
+	end
+
+	return true
+end
+
+"""
+	isirreducible(f::AbstractPolynomial, modulo::Integer) -> Bool
+	
+Checks if a polynomial is irreducible.
+	
+Parameters:
+  - f::Polynomial: The polynomial you need to check.
+  - modulo::Integer: The modulus under which you are working.
+  
+Returns:
+  - Bool: Whether or not the polynomial is irreducible (true or false).
+"""
+function isirreducible(f::AbstractPolynomial, modulo::Integer)
+	deg = length(f.coeffs) - 1
+	f = mod(f, deg)
+	polys = list_polys(deg, modulo)
+
+	for a in polys, b in polys
+		isequal(f, mod(a*b, modulo)) && return false
+	end
+
+	return true
+end
 
 """
 	normal_form!(M::AbstractArray, n::Integer) -> Matrix{Integer}

src/distance.jl

@@ -5,8 +5,6 @@
     "${BASH_SOURCE[0]}" "$@"
     =#
 
-include(joinpath(dirname(@__FILE__), "utils.jl"))
-
 """
 	hamming_distance(w₁, w₂) -> Integer
 
@@ -62,7 +60,7 @@ Returns:
   - AbstractArray: The list of words in Σⁿ whose distance from w is less than or equal to e.  Returns an array of array of symbols.
 """
 hamming_ball(Σⁿ::AbstractArray{T}, w::AbstractArray, e::Integer) where T =
-	__hamming_space(lessthanorequal, Σⁿ, w, e)
+	__hamming_space(≤, Σⁿ, w, e)
 
 """
 	hamming_sphere(Σⁿ::AbstractArray, w::AbstractArray, e::Integer) -> Vector{Vector}