Hi, if it can help, here are two remarks:
First, P.coeffs does not shortcut anything compared to P.coefficients because we have tab completion. It even slows things down: if i want coefficients, i will write P.coe<TAB> and then it will not auto-complete fully because coeffs adds a breaking node between P.coe and P.coefficients (and symmetrically) so actually removing P.coeffs will speed things up. Second, from the new user point of view, the method is called coefficients not nonzero_coefficients so people use it the straightforward way and since it works on most tested example, they will not go further in reading the doc. I have observed the problem with coefficients default behaviour some times already, see for example : http://ask.sagemath.org/question/23920/polynomial-in-gfp2/?answer=23922#post-id-23922 The main issue here is that it somehow "fails silently". A common workflow is to tab-complete for what you are looking for, if something with the right name appears, try it and use it if it works, look at the documentation only if your example did not work as expected. A test polynomial basically looks like 1+2*x+5*x^3 tried with second coeff, unlikely 1+2*x^4. Note that everything is already coded as P.dict(), P.__getitem__() and P.__iter__() so the main question is about visibility and accessibility. A newcommer is unlikely to look at the P.dict() method while tab-completing (even less P.__getitem__([2,3]) nor P([2,3])), while the word "coefficients" immediately makes sense and deserves having a try. If i had two gifts "coefficients" and "dict" to offer to a developper and a newcommer, it is not clear i would have done the current choice, newcomers are not subscribed to sage-devel however. By the way, i found 'nonzero' much easier to understand than 'sparse' in this context. Ciao, Thierry On Wed, Nov 26, 2014 at 12:06:31PM -0800, john_perry_usm wrote: > Hello Sages > > Last week (?) I noticed that a program I wrote was making a mistake, > because f.coeffs() and f.coefficients() return very different results: the > former provides a dense representation (with 0's), the second a sparse one > (no 0's, correlating with f.exponents()). > > I like this OK, but the help string isn't clear on this: the latter states > merely, "Return the coefficients of the monomials appearing in self;" while > the former states, "Returns "self.list()." " The help on self.list() states > merely, "Returns a list with the coefficients of self." > > So the difference is that one states "monomials *appearing* in self," while > the other does not clarify that it gives the monomials appearing in self, > which presumably means it includes monomials *not* appearing in self. I'm > not good at these kinds of inferences, so this does not immediately convey > "dense" or "sparse representation," or not to me, anyway. > > I would propose the following: > > *f.coeffs?* should state something to the effect of, "Returns all the > coefficients of a dense representation of f." > > *f.coefficients?* should state something like, "Returns all the > coefficients of a sparse representation of f; that is, it returns only the > non-zero coefficients, in a list correlated with f.exponents." (Notice the > explicit statement of the correlation, reinforcing sparse representation.) > > *f.list?* should be mostly identical to f.coeffs? > > I'm willing to open a ticket & author a patch to this effect, if at least > one other person agrees here. > > john perry > > -- > You received this message because you are subscribed to the Google Groups > "sage-devel" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sage-devel+unsubscr...@googlegroups.com. > To post to this group, send email to sage-devel@googlegroups.com. > Visit this group at http://groups.google.com/group/sage-devel. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To unsubscribe from this group and stop receiving emails from it, send an email to sage-devel+unsubscr...@googlegroups.com. To post to this group, send email to sage-devel@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel. For more options, visit https://groups.google.com/d/optout.
