pengcheng Xue

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These are questions asked by pengcheng Xue

Hi, I'm solving a complicated ODEs. It is a multiple point bvp. Last time I asked a question about a similar problem(you can see https://www.mapleprimes.com/questions/230626-I-Am-Trying-To-Solve-A-Set-Of-ODEs-With). And when I use the last point 's solution to obtain the next point's solution (via approxsoln=..), it works well (it's the replicate of other people's paper). But this time I changed theoretical model, so the input parameters and the equations are some different from the previous. Some problems appears again. In the code I used a loop to calculate solutions with different lambda, but the code works on some points in front, then it appears an error "initial Newton iteration is not converging". 

Do you have some ideas to overcome it?

 

dsolveODEs.mw

I am trying to solve a set of ODEs with dsolve. There are 26 equations of my ODEs, but the problem is a multiple point bvp. So the range is divided into three region. In order to use dsolve, I transform the three subregion's coordinate into 0 to 1. Meanwhile, the ODEs are different in three regions, respectively. So, there are 26×3 equations in total. And according to the paper I want to replicate, it says the response is unstable,so parameter continuation is used. Similar to the paper, an additional equation is added(eq1_27 in code), also an additional condition is added(about lambda). When the lambda is less then 0.11, the dsolve works, but for other values it doesn't work. Could anyone help me?

 

Sorry for the tedious programming code, I am new to Maple.

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