Looking through the documentation, I haven't seen any examples of using a function name without it being defined first. I've been using Maple for years and I have a lot of code that relies upon this. This also ties into a second question related to integration. Is there any way to delay the integration? Maple provides inert derivatives and integrals so you can display something as an derivative or integral and delay the evaluation until later.
The reason I ask is that I often work with functions that are unknown (e.g., variations from the calculus of variations) or are approximated (and I want to investigate the effects of different approximations). In Maple I often have integrals that have terms that look like: Int(Int(Int(Int(u(x,y,z,t)*Diff(deltau(x,y,z,t),x),x),y),z),t) If the CAS is going to try to evaluate each integral at every computational step, it can get very expensive. The simplest work around is to work with the integrands until the last step, but it isn't ideal because this means you have to keep track of what terms correspond to each integral. For instance, in the example above, you need to integrate by parts to eliminate the derivative on the deltau term. So, without the integrals in place, so bookkeeping is necessary. Thanks, Tim Lahey --~--~---------~--~----~------------~-------~--~----~ 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/sage-forum URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
