Nonlinear system of b v ps

[Calin Gheorghiu]

Dear all,

I am a fan of Chebfun and I intensively work with this package.

Unfortunately, I have some trouble solving a system of two BVPs (Numerical Solution of Nonlinear Two.Point Boundary
Problems by Finite Difference Methods, JAMES F. HOLT, 1964). I followed  the example of A. Birkisson and T. Driscoll (sept. 2010) from the Chebfun site. 

The following two sequences do not work:
[u,info] = N\[0; 0];
nrmduvec = info.normDelta;

I get the following error message:

Error using chebfun/get (line 171)
'normDelta' is not a recognized CHEBFUN property name.

Error in chebfun/subsref (line 149)
        out = get(f, idx);

Error in Holt_system (line 19)
nrmduvec = info.normDelta;

However, I have simply used the successfully command: [u] = N\0; but I have lost all the information about the convergence of Newton's method and the coefficients of solutions.

A similar situation occurs if I use the first system workaround the above mentioned authors provide.

I would fairly appreciate any suggestion in order to fix this bug.

Regards and many thanks.

Calin Gheorghiu

Dr. C. I. Gheorghiu

Senior research fellow
"T. Popoviciu" Institute of Numerical Analysis
P. O. Box 68-1
401010 Cluj-Napoca 
Romania
Phone +40 (0)744 70 18 96

http://www.ictp.acad.ro/gheorghiu

https://www.springer.com/gp/book/9783319062297

[Nick Hale]

Dear Calin

I suspect the issue is that \ is outputting first the two solutions to your ODE system (say u(x) and v(x)). The info structure in your case would be a third output argument.

Try something like

>> [u, v, info] = N\[0;0];

Best regards

Nick