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JohnRudnicki15-Moonstone
15-Moonstone
September 9, 2015
Solved

Odesolve error message

  • September 9, 2015
  • 1 reply
  • 2060 views

What does "The return value of this function must match the problem size" mean? I could not find it in the list of error messages. Instance in the attached file.

Best answer by StuartBruff

John Rudnicki wrote:

What does "The return value of this function must match the problem size" mean? I could not find it in the list of error messages. Instance in the attached file.

I don't know, but I suspect it's either related to the particular solver you've got selected or to the interpolating polynomial (this being my number one guess).  You can get round the problem by right-clicking on OdeSolve and choosing Adaptive from the context menu.u   Interestingly, this was one of the few cases I've encountered where Prime 3.1 didn't bat an eyelid and solved it straight away.

That 2.57... number you can see is the value of chat just before the Radau solver choked.

Stuart

1 reply

S
StuartBruff23-Emerald VAnswer
23-Emerald V
September 9, 2015

John Rudnicki wrote:

What does "The return value of this function must match the problem size" mean? I could not find it in the list of error messages. Instance in the attached file.

I don't know, but I suspect it's either related to the particular solver you've got selected or to the interpolating polynomial (this being my number one guess).  You can get round the problem by right-clicking on OdeSolve and choosing Adaptive from the context menu.u   Interestingly, this was one of the few cases I've encountered where Prime 3.1 didn't bat an eyelid and solved it straight away.

That 2.57... number you can see is the value of chat just before the Radau solver choked.

Stuart

J
JohnRudnicki15-MoonstoneAuthor
15-Moonstone
September 9, 2015

Thanks. I thought that changing eta, which is a kind of damping might help, but it didnt. How did you find the 2.57...number?

Still not enough reason for me to switch to Prime!

S
StuartBruff23-Emerald V
23-Emerald V
September 9, 2015

John Rudnicki wrote:

,,,How did you find the 2.57...number?

guess and iterate!  It didn't take long ... although I was tempted to write a program after the first 5 iterations. 

Still not enough reason for me to switch to Prime!

No, same here.  The image handling (or rather almost complete lack of it) is a strict no-go for me.  I'm still at the stage I was in for Mathcad 13, ie develop in 11 and convert to 13.   Similarly, I develop in M15 and then see if Prime will handle it.

Stuart

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