The issue was that I wasn't storing the Spline2D directly, but rather a
function which wrapped log10 calls around the arguments. Pulling these out
into my type's call method and directly storing the Spline inside it works
perfectly. Thanks! I guess the lesson here is "just store the data inside
the type, don't try and make it like OO by putting a function inside too".
Scott
On Friday, 14 August 2015 02:02:03 UTC+1, Scott T wrote:
>
> Thanks Kyle - looks like the error I was getting from JLD was unrelated,
> as I just managed to save a Spline2D type with it. I'll try your approach.
> Nice to hear that I can drop the collect calls as well.
>
> Scott
>
>
> On Friday, 14 August 2015 00:15:06 UTC+1, Kyle Barbary wrote:
>>
>> Hi Scott,
>>
>> Dierckx.Spline2D is simply a type that holds Vectors of spline
>> coefficients, so it should work with JLD like any other type (but I admit
>> that I’m not that familiar with JLD). I’d probably do something like this:
>>
>> using Dierckx
>>
>> type LogPTGridEOS
>> logP::LinSpace{Float64}
>> logT::LinSpace{Float64}
>> densities::Matrix{Float64}
>> spline::Spline2D
>>
>> # calculate the spline coefficients when you create a new instance
>> LogPTGridEOS(logP, logT, densities) = new(logP, logT, densities,
>> Spline2D(logP, logT, densities))
>> end
>>
>> grid = LogPTGridEOS(linspace(0.0, 1.0, 10), linspace(0.0, 1.0, 10), ones(10,
>> 10))
>>
>> using JLD
>> save("myfile.jld", "grid", grid)
>>
>> Then your call method would simply be
>>
>> call(grid::LogPTGridEOS, p, t) = evaluate(grid.spline, log10(p), log10(t))
>>
>> Note that the latest version of Dierckx can accept LinSpace, Range or
>> any AbstractVector as inputs (internally collected into a Vector).
>>
>> — Kyle
>>
>>
>> On Thu, Aug 13, 2015 at 3:41 PM, Scott T <[email protected]> wrote:
>>
>>> That's a really nice solution, thanks.
>>>
>>> Scott
>>>
>>>
>>> On Thursday, 13 August 2015 22:19:35 UTC+1, Tim Holy wrote:
>>>>
>>>> There are several possible solutions, but one is to use the new custom
>>>> serialization facilities to discard/recreate the interp_func when you
>>>> save/load the object:
>>>>
>>>> https://github.com/JuliaLang/JLD.jl/blob/master/doc/jld.md#custom-serialization
>>>>
>>>>
>>>> --Tim
>>>>
>>>> On Thursday, August 13, 2015 12:37:59 PM Scott T wrote:
>>>> > Hi everyone,
>>>> >
>>>> > I'm wondering what the most Julian way to handle the following
>>>> situation
>>>> > is. I know it can't be complicated, but am not quite sure how to go
>>>> about
>>>> > it.
>>>> >
>>>> > I'm doing some simple interpolation using Dierckx.jl
>>>> > <https://github.com/kbarbary/Dierckx.jl>, getting densities of
>>>> materials
>>>> > from a pressure-temperature pair.
>>>> >
>>>> > I have a type which holds pressure and temperature axes, and density
>>>> values
>>>> > on the (logarithmic) grid that these define:
>>>> >
>>>> > type LogPTGridEOS
>>>> > logP::LinSpace{Float64}
>>>> > logT::LinSpace{Float64}
>>>> > densities::Matrix{Float64}
>>>> > end
>>>> >
>>>> > I want to be able to easily store and load instances of this type,
>>>> and am
>>>> > using JLD.jl <https://github.com/JuliaLang/JLD.jl> for this. This
>>>> lets me
>>>> > save and load from HDF5 ".jld" files, which preserve the type
>>>> information
>>>> > (nice).
>>>> >
>>>> > To interpolate on the grid, I first need to make an interpolating
>>>> function,
>>>> > then evaluate it:
>>>> >
>>>> > function call(eos::LogPTGridEOS, P, T)
>>>> > interp_func = Dierckx.Spline2D(collect(eos.logP),
>>>> collect(eos.logT), eos
>>>> > .densities) # collect because Dierckx needs arrays
>>>> > interpolated_density = Dierckx.evaluate(interp_func, log10(P),
>>>> log10(T))
>>>> > # remember this is a log-log grid
>>>> > end
>>>> >
>>>> > But the interpolating function made in that first line could just be
>>>> called
>>>> > over and over again, avoiding any overhead from reconstructing it
>>>> (the slow
>>>> > bit). How can I best cache this function for re-use? I considered
>>>> storing
>>>> > it in the type itself by adding an "interp_func" field, but this
>>>> messes up
>>>> > saving it via JLD since JLD can't save a pointer. Am I right in
>>>> thinking I
>>>> > should make a wrapper type which holds the original type plus a
>>>> reference
>>>> > to the interpolation function, or is there a nicer way to do this?
>>>> >
>>>> > Cheers,
>>>> > Scott
>>>>
>>>>
>>
