gistfile1.jl

# T: type of underlying data
# N: dimensionality of filter
type ConvolveFilter{T,N}
	fk::Array{Complex{T},N}
end

# apply a filter to data.
# If the dimensionality of the data (M) is larger than the filter (N),
# then apply the filter to the first N dimensions of the data.
*{T,N,M}(f::ConvolveFilter{T,N},x::Array{T,M}) = real(ifft(conj(f.fk) .* fft(x,1:N), 1:N))

# transpose operation on filters is simple.
ctranspose{T,N}(f::ConvolveFilter{T,N}) = Filter1D{T,N}(conj(f.fk))

# numerical manipulation of filters
# filter $op number
for op = (:.+, :.*, :.-, :./)
  eval(quote
    ($op){T,N}(f::ConvolveFilter{T,N}, x::T)= ConvolveFilter{T,N}(($op)(f.fk, x))
  end)
  eval(quote
    ($op){T,N}(x::T, f::ConvolveFilter{T,N})= ConvolveFilter{T,N}(($op)(f.fk, x))
  end)
end
# filter $op filter
for op = (:+, :-, :.+, :.-)
  eval(quote
    ($op){T,N}(f::ConvolveFilter{T,N}, g::ConvolveFilter{T,N})= ConvolveFilter{T,N}(($op)(f.fk, g.fk))
  end)
end