Julia 中的不一致分段错误

Question

我创建了一个阻尼摆相平面的 gif 图像。为此，我将包 DifferentialEquations.jl 用于集成，将包 Plots.jl 与 pyplot 后端一起使用，将 ImageMagick.jl 用于绘图和动画。为此，我整合了不同初始值的函数，并且每个初始值都整合了很多次，所以我得到了一些小片段，这些片段共同塑造了 gif 形式的最终图。代码如下：

using DifferentialEquations
using Plots ; default(size=(1000,700))
pyplot()
using ImageMagick

x = linspace(0.0,50.0,101)
tfinal = collect(x)
b = 0.2
p = plot()
u0vals = ([pi,-2.41],[2.0*pi,-2.41],[-2.0*pi,-3.0],[-2pi,3.0])
anim = @animate for j=1:endof(tfinal)
  for i=1:endof(u0vals)
      f = function(t,u,du)
        du[1] = u[2]
        du[2] = -b*u[2] -sin(u[1])
      end
      u0 = u0vals[i]
      tspan=(0.0,tfinal[j])
      prob = ODEProblem(f, u0, tspan)
      sol = solve(prob)
      plot!(p, sol, vars=(1,2),arrow=true,legend = false, titlefont=font(15, "cursive"),title = "STRO Figure 6.7.7", linewidth=1,linecolor=:"black",xlims=(-15.0,10.0),border=false,ticks=nothing,grid=false)
  end
end
gif(anim, "STRO_6_7_7_GIF_.gif",fps=5)

我第一次使用此代码时效果很好运行。但是，我再次尝试运行更改 tfinal，结果显示：signal (11): Segmentation fault: 11（这只是来自 julia 的消息的第一行）。然后我再次尝试运行初始代码，我得到了相同的消息。重新启动 julia 和计算机后，我收到相同的消息。我再次更改了 tfinal 并且它再次工作并且适用于我想使用的每个 tfinal。我有我想要的输出。但是，令我困扰的是我的代码中的 julia "reaction" 不一致。如果需要，我可以粘贴完整的错误，但很长。

编辑：这是完整的错误信息

signal (11): Segmentation fault: 11
while loading no file, in expression starting on line 0
ode_interpolation at /Users/pacagal/.julia/v0.5/OrdinaryDiffEq/src/dense/generic_dense.jl:134
[inlined]
InterpolationData at /Users/pacagal/.julia/v0.5/OrdinaryDiffEq/src/interp_func.jl:20
unknown function (ip: 0x32b584519)
macro expansion at /Users/pacagal/.julia/v0.5/DiffEqBase/src/solutions/solution_interface.jl:72 [inlined]
apply_recipe at /Users/pacagal/.julia/v0.5/RecipesBase/src/RecipesBase.jl:238
unknown function (ip: 0x32b5808c6)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9 x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
jl_apply at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia.h:1392 [inlined]
jl_f__apply at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:547
_process_userrecipes at /Users/pacagal/.julia/v0.5/Plots/src/pipeline.jl:73
_plot! at /Users/pacagal/.julia/v0.5/Plots/src/plot.jl:171
unknown function (ip: 0x32b57bbed)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
#plot!#266 at /Users/pacagal/.julia/v0.5/Plots/src/plot.jl:151
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
jl_apply at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia.h:1392 [inlined]
jl_f__apply at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:547
#plot! at ./<missing>:0
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
macro expansion; at ./REPL[10]:11 [inlined]
macro expansion; at /Users/pacagal/.julia/v0.5/Plots/src/animation.jl:154 [inlined]
anonymous at ./<missing> (unknown line)
unknown function (ip: 0x32b5566ff)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_toplevel_eval_flex at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/toplevel.c:569
jl_toplevel_eval_in_warn at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/builtins.c:590
eval at ./boot.jl:234
jlcall_eval_19752 at /Applications/Julia-0.5.app/Contents/Resources/julia/lib/julia/sys.dylib (unknown line)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
eval_user_input at ./REPL.jl:64
unknown function (ip: 0x3192d9e66)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
macro expansion at ./REPL.jl:95 [inlined]
#3 at ./event.jl:68
unknown function (ip: 0x3192d30df)
jl_call_method_internal at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia_internal.h:189 [inlined]
jl_apply_generic at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/gf.c:1942
jl_apply at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/./julia.h:1392 [inlined]
start_task at /Users/osx/buildbot/slave/package_osx10_9-x64/build/src/task.c:253
Allocations: 40525029 (Pool: 40521241; Big: 3788); GC: 71

[Proceso completado]

Answer 1

分段错误是因为您的时间跨度很小。

x = linspace(0.0,50.0,101)
tfinal = collect(x)

然后注意tfinal[1]=0.0，所以第一个时间跨度是(0.0,0.0)。它正在做的是给出一个简单的 diffeq 解决方案，然后尝试绘制它，以边界错误结束，但边界检查已关闭。哎哟。我提交了一个提交，这样下一个补丁就会抛出一个错误，提醒用户时间跨度是微不足道的。

也就是说，解决这个问题的方法是去掉第一个时间点：

x = linspace(0.0,50.0,101)
tfinal = collect(x)[2:end]

这样就可以了。

您可能还想查看提供的 animation interface。不确定它是否可以轻松地按照您想要的顺序对所有内容进行动画处理：这可能需要更多 Plots.jl 控件。

Julia 中的不一致分段错误

Inconsistent Segmentation fault in Julia

segmentation-fault

differential-equations

julia

plots.jl