9
$\begingroup$

Bug introduced in 11.2 or earlier, fixed in 12.2 or earlier.

Reported to Wolfram with CASE number 4028951

on 11.3,

ClearAll[u,x,t]; eqn=D[u[x,t],t]+u[x,t]*D[u[x,t],x]==0; bc=u[0,t]==0; ic=u[x,0]==x; sol=DSolve[{eqn,bc,ic},u[x,t],x,t]

Mathematica graphics

What does, terms that have

 DSolve`DsolveLaplaceTransformDump`

mean in the solution? It looks like DSolve starting using the Laplace method to solve the above PDE. But is the above answer meant to be the final answer, or did DSolve gave up in the middle and these Dump messages are left there?

Improve this question
$\endgroup$
2
  • 1
    $\begingroup$ It's a context that's used by internal functions. Usually, the answer is rewritten in terms of user variables. Happens on 11.2, too. I don't think it should happen. $\endgroup$ Commented Mar 12, 2018 at 13:54
  • 5
    $\begingroup$ That's a bug, please report it. The Dump context should never leak. $\endgroup$ Commented Mar 12, 2018 at 13:56

1 Answer 1

Reset to default
4
$\begingroup$

The bug is fixed in v12.2 or earlier, now DSolve returns unevaluated:

enter image description here

It's a bit sad that DSolve still cannot solve the problem.

Improve this answer
$\endgroup$

Start asking to get answers

Find the answer to your question by asking.

Ask question

Explore related questions

See similar questions with these tags.