Make issym/ishermitian a lot faster when tol=0. is requested.

Author: dhoegh

base/linalg/generic.jl

@@ -262,7 +262,7 @@ condskeel{T<:Integer}(A::AbstractMatrix{T}, p::Real=Inf) = norm(abs(inv(float(A)
 condskeel(A::AbstractMatrix, x::AbstractVector, p::Real=Inf) = norm(abs(inv(A))*abs(A)*abs(x), p)
 condskeel{T<:Integer}(A::AbstractMatrix{T}, x::AbstractVector, p::Real=Inf) = norm(abs(inv(float(A)))*abs(A)*abs(x), p)
 
-function issym(A::AbstractMatrix)
+function _issym(A::AbstractMatrix)
     m, n = size(A)
     m==n || return false
     for i = 1:(n-1), j = (i+1):n
@@ -275,7 +275,7 @@ end
 
 issym(x::Number) = true
 
-function ishermitian(A::AbstractMatrix)
+function _ishermitian(A::AbstractMatrix)
     m, n = size(A)
     m==n || return false
     for i = 1:n, j = i:n
@@ -286,9 +286,14 @@ function ishermitian(A::AbstractMatrix)
     return true
 end
 
+ishermitian(A::AbstractMatrix) = _ishermitian(A::AbstractMatrix)
+issym(A::AbstractMatrix) = _issym(A::AbstractMatrix)
+
 for (f,t) in ((:ishermitian, :ctranspose),(:issym, :transpose))
     eval(quote
         function $f{T<:FloatingPoint}(A::Union(AbstractMatrix{Complex{T}}, AbstractMatrix{T}),tol=1e-10)
+            # This is performed due to if tol==0. _issym/_ishermitian is a lot faster for exact equality.
+            tol == 0. && return $(symbol("_",:f))(A)
             m,n = size(A)
             Tnorm = typeof(float(real(zero(T))))
             Tsum = promote_type(Float64,Tnorm)