Hi again, There were long discussion about the typesetting of partial derivatives in the new system, but I don't think we got to a conclusion yet. The previous thread is here:
http://groups.google.com/group/sage-devel/browse_thread/thread/7479c3eeb96348a2 I agree that this is annoying and trivial to typeset better: sage: version() 'Sage Version 4.0.1, Release Date: 2009-06-06' sage: f = function('f') sage: f(x).derivative(x,5) D[0, 0, 0, 0, 0](f)(x) However, how to typeset these is not so clear: sage: f(x+2*y).derivative(x,2) D[0, 0](f)(x + 2*y) sage: f(x+2*y).derivative(y,2) 4*D[0, 0](f)(x + 2*y) In these examples, keep in mind that we did not define what the first argument of the function is called, so we can't just replace D[0, 0] with d/dx. The power of this notation is seen mainly with more than one argument: sage: f(x+y, x-y).derivative(y) D[0](f)(x + y, x - y) - D[1](f)(x + y, x - y) Here is what MMA does: In[1]:= D[F[x], x] Out[1]= F'[x] In[2]:= TeXForm[%] Out[2]//TeXForm= F'(x) In[3]:= D[F[x], x, x, x, x, x] (5) Out[3]= F [x] In[4]:= TeXForm[%] Out[4]//TeXForm= F^{(5)}(x) In[5]:= D[F[x+2*y], x, x] Out[5]= F''[x + 2 y] In[6]:= TeXForm[%] Out[6]//TeXForm= F''(x+2 y) In[7]:= D[F[x+2*y], y, y] Out[7]= 4 F''[x + 2 y] In[8]:= TeXForm[%] Out[8]//TeXForm= 4 F''(x+2 y) In[9]:= D[F[x+y, x-y], y] (0,1) (1,0) Out[9]= -F [x + y, x - y] + F [x + y, x - y] In[10]:= TeXForm[%] Out[10]//TeXForm= F^{(1,0)}(x+y,x-y)-F^{(0,1)}(x+y,x-y) And Maple: > diff(f(x),x); d -- f(x) dx > diff(f(x),x$5); 5 d --- f(x) 5 dx > diff(f(x+2*y), y$2); (2) 4 (D )(f)(x + 2 y) > convert(%, diff); / 2 \| | d || 4 |---- f(t1)|| | 2 || \dt1 /|t1 = x + 2 y > diff(f(x+y, x-y), y); D[1](f)(x + y, x - y) - D[2](f)(x + y, x - y) > convert(%, diff); D[1](f)(x + y, x - y) - D[2](f)(x + y, x - y) I like the way MMA handles this. It's compact and consistent. So I suggest we change things to use the MMA convention. Comments? Cheers, Burcin --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
