So, using Tim's suggestion this would be:
# assume anything which isn't an array is scalar
u2(x, Lbox) = x>Lbox/2 ? 0 : 0.5*(u2_0(x)+u2_0(Lbox-x))-u2_0(Lbox/2)
u2(x::AbstractArray, Lbox) = map( x->u2(x,Lbox), x)
So, no code duplication. However, on the current release writing the
second function with a loop will be more preformant (and no code
duplication either).
On Wed, 2016-02-10 at 13:21, Tim Holy <tim.h...@gmail.com> wrote:
> I'm not quite sure if this is what you're asking, but if you want a scalar
> function to work elementwise on an array, try `map`.
>
> --Tim
>
> On Wednesday, February 10, 2016 04:15:30 AM Ferran Mazzanti wrote:
>> Thanks Mauro...
>>
>> using two methods was the first thing I thought, but I strongly dislike the
>> idea because I'd have to maintain two different functions
>> to do the same, which doubles the possibility of introducing bugs. I like
>> the idea of keeping the main function simple and unique,
>> so if I change something the changes apply to all calculations in the same
>> way.
>>
>> Best regards,
>>
>> Ferran.
>>
>> On Wednesday, February 10, 2016 at 12:11:00 PM UTC+1, Mauro wrote:
>> > Probably cleanest would be to make two methods, one for scalars, one for
>> > arrays. For the array one just loop.
>> >
>> > This also works, but returns an array for scalar input (type inference
>> > should work once wrapped in a function):
>> >
>> > julia> x = 5
>> > 5
>> >
>> > julia> [ xi>5 ? 0:1 for xi in x]
>> >
>> > 1-element Array{Any,1}:
>> > 1
>> >
>> > julia> x = 1:10
>> > 1:10
>> >
>> > julia> [ xi>5 ? 0:blah for xi in x]
>> >
>> > 10-element Array{Any,1}:
>> > 1
>> > 1
>> > 1
>> > 1
>> > 1
>> > 0
>> > 0
>> > 0
>> > 0
>> > 0
>> >
>> > On Wed, 2016-02-10 at 11:58, Ferran Mazzanti <ferran....@gmail.com
>> >
>> > <javascript:>> wrote:
>> > > Hi folks,
>> > >
>> > > probably a stupid question but can't find the answer, so please help if
>> >
>> > you
>> >
>> > > can :)
>> > > I would like to evaluate a if.. else.. statement on a whole array.
>> >
>> > Actually
>> >
>> > > it's a bit more complicated, as I have a function that
>> > > previously was
>> > >
>> > > function u2(x)
>> > >
>> > > return 0.5*(u2_0(x)+u2_0(Lbox-x))-u2_0(Lbox/2)
>> > >
>> > > end;
>> > >
>> > > for some other defined function u2(x) and constant L_box. The thing is
>> >
>> > that
>> >
>> > > I could directly evaluate that on a scalar x and on an array.
>> > > Now I have to change it and check if x is smaller than Lbox/2, returning
>> > > the same as above if it is, or 0 otherwise.
>> > > I tried something of the form
>> > >
>> > > function u2(x)
>> > >
>> > > return x.>Lbox/2 ? 0 : 0.5*(u2_0(x)+u2_0(Lbox-x))-u2_0(Lbox/2)
>> > >
>> > > end;
>> > >
>> > > but that complains when x is an array. What would be the easiest way to
>> > > achieve this? It should work for both scalars and arrays...
>> > >
>> > > Best regards and thanks,
>> > >
>> > > Ferran.
