Is this NDSolve error new in 10.3?

Questions
1

I believe the attached file ran without errors in 10.2, but in 10.3 In[8] results in:

sol = NDSolveValue[equations /. values, {x[t], y[t]}, {t, 0, 500}];

NDSolve::depdole: The differential order of a dependent variable in {(x^\[Prime])[t],(x^\[Prime]\[Prime])[t],(y^\[Prime])[t],(y^\[Prime]\[Prime])[t]} exceeds the highest order that appears in the differential equations. >>

NDSolve::depdole: The differential order of a dependent variable in {(x^\[Prime])[t],(x^\[Prime]\[Prime])[t],(y^\[Prime])[t],(y^\[Prime]\[Prime])[t]} exceeds the highest order that appears in the differential equations. >>

NDSolve::depdole: The differential order of a dependent variable in {(x^\[Prime])[t],(x^\[Prime]\[Prime])[t],(y^\[Prime])[t],(y^\[Prime]\[Prime])[t]} exceeds the highest order that appears in the differential equations. >>

General::stop: Further output of NDSolve::depdole will be suppressed during this calculation. >>

But I do not see the source of the error. Can anyone else identify the issue?

Kind regards, David

2

Dear David,

I can reproduce that. It does seem to work before 10.3. All 10.3+ versions do not work, e.g.

ScreenShot2015-12-21at19.43.19.png

Cheers,

Marco

3

Thank you, Marco. I’ll send it in to tech support.

Best,

David

4

Tech support confirms they have reproduced the error and forwarded it to development. When I receive notice of a workaround or fix I’ll update this post.

5

Dear David,

thanks a lit for the update. The good thing is that with the current update cycles these thing usually get fixed quite quickly.

Thanks a lot and I wish you very nice, festive days,

Marco

6

Confirmed as a bug in event processing. For a possible workaround in this case, try

Method → {Automatic, “DiscontinuityProcessing” → False}

7

Attached fixes it! I reduced the 2 second order equations to 4 first order equations