Re: Plot in function
- To: mathgroup at smc.vnet.net
- Subject: [mg128435] Re: Plot in function
- From: Daniel <dosadchy at its.jnj.com>
- Date: Fri, 19 Oct 2012 02:42:43 -0400 (EDT)
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- Delivered-to: l-mathgroup@wolfram.com
- Delivered-to: mathgroup-newout@smc.vnet.net
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>
> I would like to make a function that plots a variable
> over a parameter range. I tried:
>
> test[f_, sol_] :=
> Table[Plot[
> f /. DeleteCases[sol, i], {i[[1]], 0.9 i[[2]], 1.1
> 1.1 i[[2]]}], {i,
> sol}]
>
> But this gives the error:
>
> test[x^2 + y^2, {x -> 0, y -> 0}]
>
> During evaluation of In[108]:= Plot::write: Tag Part
> in i[[1]] is Protected. >>
>
> I see that i cannot define a part in the variable of
> a plotfunction, but also if I first assign i[[1]] to
> a variable, I get a problem with the bounds.
>
> test[f_, sol_] :=
> Table[a = i[[1]];
> Plot[f /. DeleteCases[sol, i], {a, 0.9 i[[2]], 1.1
> .1 i[[2]]}], {i,
> sol}]
>
> I don't know of a good solution. Thanks in advance.
>
First, the expression {i[[1]], 0.9 i[[2]], 1.1 i[[2]]} is not good in your case as both limits evaluate to 0.
Other that this, you're missing Evaluate[]:
test[f_, sol_] :=
Table[Plot[f /. DeleteCases[sol, i], {i[[1]], i[[2]] - 1, i[[2]] + 1}//Evaluate], {i, sol}]
test[x^2 + y^2, {x -> 0, y -> 0}] - draws 2 plots