backport bug fix, others

Author: jverzani

Project.toml

@@ -2,7 +2,7 @@ name = "Polynomials"
 uuid = "f27b6e38-b328-58d1-80ce-0feddd5e7a45"
 license = "MIT"
 author = "JuliaMath"
-version = "1.2.0"
+version = "1.2.1"
 
 [deps]
 Intervals = "d8418881-c3e1-53bb-8760-2df7ec849ed5"

src/common.jl

@@ -273,7 +273,13 @@ end
 Check if either `p` or `q` is constant or if `p` and `q` share the same variable
 """
 check_same_variable(p::AbstractPolynomial, q::AbstractPolynomial) =
-    (Polynomials.isconstant(p) || Polynomials.isconstant(q)) || p.var ==  q.var
+    (isconstant(p) || isconstant(q)) || p.var ==  q.var
+function assert_same_variable(p::AbstractPolynomial, q::AbstractPolynomial)
+    check_same_variable(p,q) || throw(ArgumentError("Polynomials have different indeterminates"))
+end
+function assert_same_variable(X::Symbol, Y::Symbol)
+    X == Y || throw(ArgumentError("Polynomials have different indeterminates"))
+end
 
 #=
 Linear Algebra =#
@@ -412,6 +418,11 @@ Is the polynomial  `p` a constant.
 """
 isconstant(p::AbstractPolynomial) = degree(p) <= 0
 
+"""
+    constantterm(p::AbstractPolynomial)
+return `p(0)`, the constant term in the standard basis
+"""
+constantterm(p::AbstractPolynomial{T}) where {T} = p(zero(T))
 
 
 
@@ -510,6 +521,13 @@ Base.hash(p::AbstractPolynomial, h::UInt) = hash(p.var, hash(coeffs(p), h))
 
 #=
 zero, one, variable, basis =#
+"""
+    indeterminate(p::AbstractPolynomial)
+
+Return polynomial indeterminate (symbol)
+"""
+indeterminate(p::AbstractPolynomial) = p.var
+
 """
     zero(::Type{<:AbstractPolynomial})
     zero(::AbstractPolynomial)

src/polynomials/ngcd.jl

@@ -10,7 +10,7 @@ In the case `degree(p) ≫ degree(q)`,  a heuristic is employed to first call on
 function ngcd(p::P, q::Q, args...;kwargs...) where {T, S, P<:StandardBasisPolynomial{T}, Q <: StandardBasisPolynomial{S}}
 
     degree(p) < 0  && return (u=q,      v=p, w=one(q),  θ=NaN, κ=NaN)
-    degree(p) == 0 && return (u=one(q), v=p, w=zero(q), θ=NaN, κ=NaN)
+    degree(p) == 0 && return (u=one(q), v=p, w=q,       θ=NaN, κ=NaN)
     degree(q) < 0  && return (u=one(q), v=p, w=zero(q), θ=NaN, κ=NaN)
     degree(q) == 0 && return (u=one(p), v=p, w=q,       θ=NaN, κ=NaN)
     check_same_variable(p,q) || throw(ArgumentError("Mis-matched variables"))
@@ -264,8 +264,8 @@ end
 # return guess at smallest singular value and right sinuglar value, x
 # for an upper triangular matrix, V
 function smallest_singular_value(V::AbstractArray{T,2},
-                                 atol=eps(T),
-                                 rtol=zero(T)) where {T}
+                                 atol=eps(real(T)),
+                                 rtol=zero(real(T))) where {T}
 
     R = UpperTriangular(V)
     k = size(R)[1]/2

src/polynomials/standard-basis.jl

@@ -25,6 +25,7 @@ mapdomain(::Type{<:StandardBasisPolynomial}, x::AbstractArray) = x
 
 ## generic test if polynomial `p` is a constant
 isconstant(p::StandardBasisPolynomial) = degree(p) <= 0
+constantterm(p::StandardBasisPolynomial) = p[0]
 
 Base.convert(P::Type{<:StandardBasisPolynomial}, q::StandardBasisPolynomial) = isa(q, P) ? q : P([q[i] for i in 0:degree(q)], q.var)