
a{T<:Real}(x::T,t::T)=one(x)*one(t)
b{T<:Real}(x::T,t::T)=zero(x)*zero(t)
c{T<:Real}(x::T,t::T)=zero(x)*zero(t)

s{T<:Real}(t::T)=exp(t)
sp{T<:Real}(t::T)=exp(t)
u{T<:Real}(x::T,t::T)=exp(-pi^2*t)*cos(pi*x)
ux{T<:Real}(x::T,t::T)=pi*exp(-pi^2*t)*sin(pi*x)
ut{T<:Real}(x::T,t::T)=-pi^2*exp(-pi^2*t)*sin(pi*x)


γf{T<:Real}(x::T,t::T)=one(x)*one(t)
