[MUG] 4 examples - an explanation?

[MUG] Re: 4 examples - an explanation?
Author: Maple User Group    Posted: Tue, 11 Jun 2002 17:30:57 -0400
>> From: Maple User Group "maple_gr" > >> From: Vladimir Bondarenko "vvb" > However, if I eliminate the multiplication operator, '*', > >1956(1+1)^2; > 3825936 # = 1956^2 > >1994(diff(aleph,a)+y(z)+ISSAC-2003)^2; > 3976036 # = 1994^2 > Could I hear an explanation? -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- Date: Wed, 5 Jun 2002 13:26:57 -0700 (PDT) From: Robert Israel "israel" To: "maple-list" Subject: 4 examples - an explanation? Eliminating the * in a*(...) gives you a(...), which is interpreted as the function a evaluated at "...". Numbers are considered as constant functions when necessary. This allows algebra to be performed on functions, e.g. > g:= f^2 + 3*f + 2: g(p); 2 f(p) + 3 f(p) + 2 Robert Israel "israel" Department of Mathematics http://www.math.ubc.ca/~israel University of British Columbia Vancouver, BC, Canada V6T 1Z2 -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- Date: Wed, 05 Jun 2002 13:34:48 -0700 To: "maple-list" From: David Harrington "dharr" Subject: 4 examples - an explanation? I think 1956() is a function that returns the constant 1956, no matter what its argument is. You can see that type('1956()',function); returns true. However, Maple immediately simplifies it to 1956 and it no longer behaves like a function: type(1956(),function); returns false. So 1956(1+1)^2; returns 1956^2 but 1956*(1+1)^2; returns 1956*4 (not 1956^2). -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- Date: Thu, 06 Jun 2002 09:33:38 +0200 From: Adri van der Meer "A.W.J.vanderMeer" To: "maple-list" Subject: 4 examples - an explanation? If the `*` operator is omitted, the syntax becomes "name(arguments)" that is a function call. Maple accepts a constant as a procedurename, as can be seen in: > f := x -> 1956; f := 1956 > 1956(x,y,z); 1956 This explains your results. -- A. van der Meer Dept. Applied Mathematics University of Twente Phone +31 (53) 4893427 P.O. Box 217 Fax +31 (53) 4894824 7500 AE Enschede -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- From: "Dr Francis J. Wright" "F.J.Wright" To: "\"Vladimir Bondarenko\"" "vvb" Subject: 4 examples - an explanation? Date: Thu, 6 Jun 2002 12:46:22 +0100 Maple treats the form `number(...)' as a constant function, which evaluates to `number' (ignoring what appears within the parentheses). It performs this calculation first, and then squares the result. Francis -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- Date: Thu, 6 Jun 2002 16:17:25 +0100 To: "maple-list" From: Nicolas PUECH "puech" Subject: 4 examples - an explanation? In the second series of examples, just as one uses to consider things in mathematical notation, MAPLE considers that 1956(1+1) is the application of the constant function x->1956 to the value 2 which leads to the result 1956. The same holds for 1994(diff.....)^2. Nicolas PUECH INFRES Ecole Nationale Superieure des Telecommunications -=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=-=*=- From: Stanley J Houghton "S.J.Houghton" Date: Fri, 7 Jun 2002 15:36:45 +0100 To: "maple-list" "vvb" Subject: 4 examples - an explanation? In Maple by definition <number>(<anything>) evaluates to <number>. Hence, 45(<anything>)= 45 I have encountered this as a rather involved bug (due to a mistyped expression) and would prefer that error checking could be switched on for this particular form (where a constant is in place of a function). However, other manipulations may rely on the convention. At least Maple is consistent in that x->45 evaluates to 45 as well! Can others help on this one? Regards Stan

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