On Mon, Feb 20, 2012 at 11:21 PM, Harold E. <[email protected]> wrote: > On 20 fév, 15:19, Aaron Meurer <[email protected]> wrote: >> >> If you're not going to use units until the very end, they're not very >> useful. Granted, there is a certain level of physical correctness >> that is lost without them, but I think the whole point of having a >> strong units system is that it can do dimensional analysis for you. >> This means that you use them in every point in the calculation, so >> that at the end, you know exactly the units of the end result. > > I'm not sure to understand exactly what you mean, but I answer anyway, > so say me if I'm wrong. > My main point was that during computation, you can write either 0.7*c > or just 0.7 when you have a velocity, and, in the first case, having > method to see if we have to add c factors. It means as you say that > the system can do dimensional analysis. But also maybe it's not very > useful, and so we can encourage user to be consistent when using units > if they want detailed results. > I did not yet have thought to this point in deep, but I think it's > possible to get something usable.
I'm inclined to strongly agree with Aaron. Dimensional analysis is often a relatively cheap way to check the physical meaning of the computation, as far as I can remember. I think that this feature would not only be very useful, but it also should be made imperative, i.e., the user should be forced to use units in all cases where this is appropriate. On the other hand, being strict with specifying units will simplify your life as the developer of this module: you will always know that constants are dimensionless, whatever the context. Sergiu -- You received this message because you are subscribed to the Google Groups "sympy" group. 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.
