On Mon, 18 Jun 2001, Christian Bauer wrote:
On Mon, Jun 18, 2001 at 03:36:39PM +0200, Do Hoang Son wrote:
c=subs(b,log($1)==Log($1)); unknown function 'Log' ... Of course, Log() is undefined one.
Correct. So?
It would be nice if such a substitution is accepted in ginsh.
But there is no function named "Log" in GiNaC. What is ginsh supposed to do? Modify inifcns.h/.cpp and recompile GiNaC?
Hmmm, I don't know. Just look at Maple
c:=ln(x*y)*z; subs(ln=foo,c); foo(x*y)*z
or in Mathematica In[1]:= c=Log[x*y]*z Out[1]= z Log[x y] In[2]:= c//. Log[a__]-> foo[a] Out[2]= z foo[x y] There is not any problem there. One offent uses this trick to get rid of troubles that caused by a difined/internal functions. Don't tell me if it is stupid or not. Just want to know if this well known feature is possible to be implemented in ginsh? Son