Am 22.05.2013 22:50, schrieb Luc Maisonobe: > I am not sure I understood your use case properly. I'll look at it further in > the next few days. > > A first very quick answer is that the interface as it is defined does not > seem to correspond to your needs. > In the current interface, the meaning of the two "value" method is the same. > So the various elements in > The point array should be the same. In your case, I think you already use the > array to represent derivatives > of the first element, so I think you expanded the content of what should be a > single DerivativeStructure instance as a double array. > > Are you sure you should not use a univariate function ? The > DerivativeStructure argument you would get > would contain all the partial derivatives already. > > Once again, I'm not sure I understood your example properly as I did not find > the time to think about it for now. > > Best regards, > Luc
Hi Luc, I am trying to motivate the problem: Consider the simple pendulum equation x² + y² - L² = 0 I could use DerivativeStructure to solve for that equation by using e.g. NewtonRaphson. But in a model, x and y are actually depending on the free variable t, so I may require the total derivative of the above equation, e.g.: 2*x*dx + 2*y*dy = 0 Again, I want to be able to solve for that equation by using an iterative method. The thing is: This total derivative has now more parameters than the original equation (namely dx and dy). If I model it that way, I can pass the x and y parameters to the base function, evaluate the partial derivatives (2x and 2y) and multiply them with the total derivatives dx and dy. The problem here is that the base-equations partial derivatives are not constant (the second order partial derivatives are, though). So I somehow need to reflect that for the numerical solver. That's why I thought, I should make the derivative also a MultivariateDifferentialFunction. -- Christoph Höger Technische Universität Berlin Fakultät IV - Elektrotechnik und Informatik Übersetzerbau und Programmiersprachen Sekr. TEL12-2, Ernst-Reuter-Platz 7, 10587 Berlin Tel.: +49 (30) 314-24890 E-Mail: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
