Re: Debug program
- To: mathgroup@smc.vnet.net
- Subject: [mg10945] Re: [mg10866] Debug program
- From: seanross@worldnet.att.net
- Date: Sat, 14 Feb 1998 00:53:19 -0500
- References: <199802112332.SAA19012@smc.vnet.net.>
Chik Tai Wai David wrote:
>
> Dear,
>
> I am using mathematica to write a program that solves a differential
> equation by finite difference method ( one of numerical methods ). I
> use Table[] to generate a set of linear equations and try to use
> Table[Solve[]] to solve for the unknowns. But an error message of
> something like "general::ivar:X[1],X[2],X[3] is not an valid variable"
> appears. I don't know what is wrong so would any one can do me a favor
> ? My program file is attached as "trial.nb". Just read the last cell
> first to see my problem. Thank you very much !
>
> Regards,
> David Chik. (email:h9505865@hkusua.hku.hk)
>
soln=Solve[eqns,Table[Temp[i,j],{i,0,6},{j,0,4}]]
General::"ivar":
"({(Temp[(6, 0)]), (Temp[(6, 1)]), (Temp[(6, 2)]), (Temp[(6, 3)]),
(Temp[(6, 4)])}) is not a valid variable."
"Solve[eqns, vars] attempts to solve an equation or set of equations for
the variables vars. Solve[eqns, vars, elims] attempts to solve the
equations for vars, eliminating the variables elims."
name[0,0] is not a variable, it is a symbol evaluated at a certain point
0,0. Since it seems like you are dealing with a matrix problem, why
not use lists? Instead of having a function k and temp etc that are
defined at a myriad of specific points, why not have a list k and a
list temp that have many elements.
--
Remove the _nospam_ in the return address to respond.
- References:
- Debug program
- From: Chik Tai Wai David <h9505865@hkusua.hku.hk>
- Debug program