How Does Changing Boundary Conditions Affect Nonlinear Shooting Methods in BVPs?

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SUMMARY

The discussion focuses on the application of nonlinear shooting methods to boundary value problems (BVPs), specifically when boundary conditions change from fixed values to fixed slopes. The participants confirm that it is valid to reduce the BVP to a second-order initial value problem (IVP) with a fixed initial slope, using methods such as the bisection algorithm and Newton's method for implementation. A successful trial problem demonstrates the effectiveness of this approach, indicating that varying initial displacement instead of slope can be a viable strategy in nonlinear shooting methods.

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  • Understanding of boundary value problems (BVPs)
  • Familiarity with nonlinear shooting methods
  • Knowledge of numerical methods, specifically bisection and Newton's method
  • Basic concepts of initial value problems (IVPs)
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  • Research "Nonlinear Shooting Method for BVPs" for foundational knowledge
  • Study "Bisection Algorithm in Numerical Analysis" for implementation techniques
  • Explore "Newton's Method for Nonlinear Equations" to adapt it for BVPs
  • Investigate "Fixed Slope Boundary Conditions in BVPs" for theoretical insights
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Mathematicians, numerical analysts, and engineers working on boundary value problems, particularly those interested in nonlinear shooting methods and numerical solution techniques.

radiogaga35
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Given the boundary value problem (primes denote differentiation w.r.t x):
[tex]\begin{array}{l}<br /> y'' = f(x,y,y') \\ <br /> y(a) = \alpha \\ <br /> y(b) = \beta \\ <br /> \end{array}[/tex]

the nonlinear shooting method may be implemented to solve the problem. A bisection algorithm may be used or, with a little more effort, Newton's method may be implemented (in which case one solves a fourth order, and not a second order, IVP - http://www.math.utah.edu/~pa/6620/shoot.pdf" ).

But what happens if the form of the boundary conditions changes to:
[tex]\begin{array}{l}<br /> y'(a) = \alpha \\ <br /> y(b) = \beta \\ <br /> \end{array}[/tex]

Is one still justified in reducing the BVP to a 2nd order IVP, but this time with initial SLOPE fixed at [tex]y'(a) = \alpha[/tex] and then trying different values of [tex]y(a)[/tex] in order to achieve the condition [tex]y(b) = \beta[/tex]? (As opposed to varying initial slope to achieve second condition).

Furthermore, if this will indeed work, then a bisection method should be easy to implement, but what about adapting Newton's method for this case? Can anyone point me to an appropriate reference that discusses this matter?

Thank you! :-)
 
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Ok, I applied the aforementioned approach (with appropriately-adapted Newton-method implementation) to a trial problem and it worked perfectly.

In principle it seems like a sensible enough approach, but I'm not very clued up on BVP methods, so I'm not sure if there is any theoretical reason to avoid this approach? I.e. varying the initial "displacement" instead of slope. Certainly I've only ever seen the initial slope being varied in simple, single shooting methods
 

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