Thanks! Here's my working version:
type FIR{in_t, coef_t}
in::Vector{in_t}
coef::Vector{coef_t}
function FIR (in::Vector{in_t}, coef::Vector{coef_t})
new (zeros (in_t, size (in)), copy (coef))
end
end
FIR{in_t, coef_t} (in::Vector{in_t}, coef::Vector{coef_t}) = FIR{in_t, coef_t}
(in, coef)
w = zeros (Float64, 10)
g = FIR{Float64,Float64} (w,w)
f = FIR(w,w)
I'm surprised (shocked) by the comment about whitespace after the name of the
function. I may find it hard to love a language where the addition of
whitespace produces ambiguity. (Not to mention, I always put whitespace
between
name of function and args)
John Myles White wrote:
> Hi Neal,
>
> I think rewriting your code to follow a little bit more conventional Julia
> style will help you to see where you’ve gone wrong:
>
> type FIR{S, T}
> in::Vector{S}
> coef::Vector{T}
> function FIR(in::Vector{S}, coef::Vector{T})
> new(zeros(S, size(in)), coef)
> end
> end
>
> FIR{S, T}(in::Vector{S}, coef::Vector{T}) = FIR{S, T}(zeros(S, size(in)),
> coef)
>
> w = zeros(Float64, 10)
> f = FIR(w,w)
>
> Note that you must include the outer constructor definition or you will not
> have access to the custom inner constructor that you’ve defined. This is one
> of the unusual properties of how parametric types work.
>
> Also worth noting that, because of ambiguities, Julia may one day need to
> prohibit function invocation with spaces between function names and
> parentheses. So it’s better to write FIR(a, b) than to write FIR (a, b).
>
> — John
>
> On Jul 30, 2014, at 8:00 AM, Neal Becker
> <[email protected]> wrote:
>
>> As a learning exercise, I am trying to code a simple FIR filter.
>> As a start, it has 2 fields and a constructor:
>>
>> type FIR{in_t, coef_t}
>> in::Vector{in_t}
>> coef::Vector{coef_t}
>> FIR (in_::Vector{in_t}, coef_::Vector{coef_t}) = (x=new(); x.in =
>> zeros(in_t, size (in_)); x.coef = coef_;)
>> end
>>
>> w = zeros (Float64, 10)
>> f = FIR{Float64,Float64}(w,w)
>>
>> This code executes, but seems very confused:
>> julia> typeof(f)
>> Array{Float64,1}
>>
>> Huh? I expected "f" to be of type FIR{Float64,Float64}. Clearly I'm doing
>> something very wrong.
>>
