Re: Interpretation of subscripts

*To*: mathgroup at smc.vnet.net*Subject*: [mg48082] Re: Interpretation of subscripts*From*: drbob at bigfoot.com (Bobby R. Treat)*Date*: Tue, 11 May 2004 05:20:04 -0400 (EDT)*References*: <c7hrfh$bjb$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I rarely use subscripted symbols directly. Instead, I use the following function: subFunction[a_Symbol] := Block[{aa = ToString[a]}, MakeExpression[SubscriptBox[ ToString[a], i_], f_] := MakeExpression[RowBox[{ToString[a], "[", i, "]"}]]; MakeBoxes[a[i_], f_] := SubscriptBox[MakeBoxes[a, f], MakeBoxes[i, f]]] Invoke that on the symbol m with subFunction[m] Now if you type m[Sun], it looks like the subscripted form in output, and if you input the subscripted form it looks subscripted but is evaluated as m[Sun]. If you want it to have the subscripted look in an input line either input it subscripted or else highlight it, right-click, and select Evaluate in Place. (The latter method doesn't work if m[Sun] has a value, of course.) subFunction[m] Solve[m[Sun]^2 == m[Sun] + 1] {{m[Sun] -> (1/2)* (1 - Sqrt[5])}, {m[Sun] -> (1/2)* (1 + Sqrt[5])}} That's InputForm; in the actual output, m[Sun] is the subscripted form. Now enter m/@Range[10] or m/@{Sun,Moon,Earth} and check out the results. Bobby dquark at gmx.de (Guido) wrote in message news:<c7hrfh$bjb$1 at smc.vnet.net>... > I wanted to solve a differential equation via DSolve. When naming the > constants with subscripts (e.g. for the mass of the sun M_Sun with the > word Sun on the line), Mathematica 5 in some way misinterpreted this > and told me: > DSolve::bvfail : For some branches of the general solution, unable > to solve the conditions. > It works, when I leave out the subscripts and name the mass of the sun > simply M and the mass of a planet m, but for optical reasons it would > be nice to have subscripts for better understanding. > I also tried this with Mathematica 4.2 in university - and it worked > fine, but I only have version 5 in my office. > In help files it is said, that Mathematica wouldn't interprete > subscipts in any other way than as names, but obviously it does... > Is there any point in preferences to tell the programm how it should > handle these things? > > I'm grateful for any help > > Guido