ChrisRackauckas

98 ms·

901.
by ChrisRackauckas 9y ago
By who? Someone who isn't part of the development team? There was an issue set for v0.5 called "Arraypocolypse" that was meant to change a ton of things related to arrays, and that was known months (a year?) before v0.5 was o
902.
by ChrisRackauckas 9y ago
If you need something stable, wait until a bit after 1.0, like you would with any Windows release. Right now it's expected that things will change and break with language updates, but the next one is the 1.0 which is the "we stop
903.
by ChrisRackauckas 9y ago
I learned C because of classes in MPI and I tried to go back to it after years of Python and MATLAB but the amount of boilerplate code and the workflow slowed me down too much. C++ is definitely a fine choice if you are a great programmer b
904.
by ChrisRackauckas 9y ago
The problem is, I needed the library. I didn't have the time and resources to build it in Python, while it was a night project for a week to build it in Julia. As a methods researcher I'm going to use the tool that doesn't im
905.
by ChrisRackauckas 9y ago
You just do @. and you're done?
906.
by ChrisRackauckas 9y ago
Thanks for bringing this up. It may be more of a domain-specific use of the terms. In science and math, most of the people who are "programming" are not really that deep into programming. Most people go to a workshop on "here
907.
by ChrisRackauckas 9y ago
@attractivechaos I don't know how to reply to your last reply, so I'll do it here. 1:length(A) is bad because it's using a standard construction for intervals of numbers, but using it for indices. We don't want to get ri
908.
by ChrisRackauckas 9y ago
1) No, they are just different dispatches to getindex. 2) No, iteration is through indices(A) or eachindex(A), etc., which are the preferred way of iterating anyways. You shouldn't do 1:length(A) which is a MATLABism that works but I w
909.
by ChrisRackauckas 9y ago
it is in the original language design which is all about type-genericness and separation of implementation from interface with zero-cost abstractions. Creating an array with a different `getindex` dispatch is a great example of what Julia&#
910.
by ChrisRackauckas 9y ago
I don't find it strange: I wrote this to say why I like using Julia and point out what the community is missing, not as a comparison to every other JIT in existence. But if you want to know why I gave up on Cython, I'll lay it out
911.
by ChrisRackauckas 9y ago
Finally got on campus to be able to read the paper in detail. It's an interesting method but it doesn't really seem to have a clear "best use case". It is a Rosenbrock-W (or ROW) type of method, which means that it'
912.
by ChrisRackauckas 9y ago
Multigrid methods are linear solvers. Generally they are only not used in the context of timestepping. PDEs will be a separate post.
913.
by ChrisRackauckas 9y ago
Yup, that's exactly what I mean. People have pre-written solvers for specific equations. Sounds like you found one for you, so that's great! When you ask about PDE tools though, people start talking about tools for building PDE so
914.
by ChrisRackauckas 9y ago
Talking about PDEs is way more complex and I didn't get into it. What do you mean by a good PDE solver? Generally a PDE solver is built by doing some spatial discretization and then either solving that with some numerical linear solver
915.
by ChrisRackauckas 9y ago
Yeah, I'm not sure of any others. But looking at numeric.js, it has a single ODE solver which is Dopri, and thus matches the tableau of ode45 and dopri5. However, it's easy to see that their implementation is very different just b
916.
by ChrisRackauckas 9y ago
Well vanilla ODE solvers are a dime a dozen. Sufficiently optimized stiff ODE solvers tend to get around the same efficiency, with some methods doing better on some problems, and others doing better on other problems. So it's all probl
917.
by ChrisRackauckas 9y ago
I went ahead and ran some stuff on my laptop. using DifferentialEquations van = @ode_def_noinvhes VanDerPol2 begin dy = μ*((1-x^2)*y - x) dx = 1*y end μ=>1. prob = ODEProblem(VanDerPol2(μ=1e6),[0;2.],(0.0,
918.
by ChrisRackauckas 9y ago
I don't think this really backs up your statement though. I am not at all surprised by this result. In the post I mentioned that MATLAB wasn't really designed for efficiency, and in this repo I show how even with explicit Runge-Ku
919.
by ChrisRackauckas 9y ago
We're setting up parameter estimation in DifferentialEquations.jl with both Stan.jl and Turing.jl as separate but connected projects. For generated data from the Lotka-Volterra equations, Turing.jl seems to be able to recover the four
920.
Building a Web App in Julia: DifferentialEquations.jl Online(stochasticlifestyle.com)
2 points by ChrisRackauckas 10y ago|0 comments
921.
by ChrisRackauckas 10y ago
6 months is a long time ago in Julia land. Since then, the standard Julia install is a minor version higher which makes -O3 optimization standard, has . syntax for automatic fused broadcasts (simple loop fusing for MATLAB-style vectorizatio