Hi, If we can treat C1 also as a variable 'y' then it won't lost its properties, as variable do not couple up and simplify to form a new variable. So may be this can work.
regards-- Abhishek Aggarwal Computer Science 2nd year IIT DELHI On Thursday, 15 March 2012 09:44:33 UTC+5:30, Aaron Meurer wrote: > > Hi. > > I just created http://code.google.com/p/sympy/issues/detail?id=3148. > The issue is related to constantsimp() in the ODE module. Basically, > right now, it converts things like 2*C1 + C1**2*x + (C1 + 1)*x**2 into > C1 + C2*x + C3*x**2. In other words, it absorbs C1, C2, ... constants > into other constants and into each other, and then renumbers them, > because they are no longer the same constant. > > I think this is a bad idea, because it makes it look like C1, C2, and > C3 are independent of each other, when they really aren't (because, in > this example, C2 = C1**2/4 and C3 = C1/4 + 1). What I think it should > do instead is return something like C1 + C1**2/2**2 + (C1/4 + 1)*x**2. > In other words, simplify one constant, and rewrite the others in > terms of it. > > The question is, how do you determine how to do this? Has anyone ever > considered such an algorithm? The idea is that you have an > over-determined system of several equations, and you want to rewrite > the equations in terms of some new unknowns so that the whole system > becomes simpler. I think that idea could also be useful in solve(), > except there you also need to care about the relationship between the > new system variables and the old ones, and how simple they are. > > Does anyone have any thoughts on how this could be achieved? > > Aaron Meurer > > -- You received this message because you are subscribed to the Google Groups "sympy" group. To view this discussion on the web visit https://groups.google.com/d/msg/sympy/-/ToiFX5e1vb8J. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/sympy?hl=en.
