小编php*_*cky的帖子

我正在尝试使用 Julia 中的 DifferentialEquations 解决谐振子。IE：

using DifferentialEquations
using Plots

m = 1.0                          
? = 1.0                     

function mass_system!(ddu,du,u,p,t)
    # a(t) = (1/m) w^2 x 
    ddu[1] = (1/m)*(?^2)*u[1]
end

v0 = 0.0                     
u0 = 1.0                  
tspan = (0.0,10.0)               

prob = SecondOrderODEProblem{isinplace}(mass_system!,v0,u0,tspan,callback=CallbackSet())
sol = solve(prob)

但它似乎并不理解 ODE 构造函数。运行后，我得到：

ERROR: LoadError: TypeError: non-boolean (typeof(isinplace)) used in boolean context
Stacktrace:
 [1] #_#219(::Base.Iterators.Pairs{Symbol,CallbackSet{Tuple{},Tuple{}},Tuple{Symbol},NamedTuple{(:callback,),Tuple{CallbackSet{Tuple{},Tuple{}}}}}, ::Type{SecondOrderODEProblem{DiffEqBas
e.isinplace}}, ::Function, ::Float64, ::Float64, ::Tuple{Float64,Float64}, ::DiffEqBase.NullParameters) at /Users/brandonmanley/.julia/packages/DiffEqBase/avuk1/src/problems/ode_problems
.jl:144
 [2] Type at ./none:0 [inlined] (repeats 2 times)
 [3] top-level scope at /Users/brandonmanley/Desktop/nBody/nBodyNN/test.jl:25 …