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MathGroup Archive 2001

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Re: Solve InterpolatingFunction problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31881] Re: Solve InterpolatingFunction problem
  • From: bghiggins at ucdavis.edu (Brian Higgins)
  • Date: Sun, 9 Dec 2001 06:07:04 -0500 (EST)
  • References: <9uss9d$cl6$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Jasem"  use FindRoot instead of Solve .  For example

mySin = Interpolation[Table[{x, Sin[x]}, {x, 0, 5, .2}]];

In[4]:=FindRoot[mySin[x] == .5, {x, 1}]

Out[4]={x -> 0.523618}

Cheers, 

Brian

"Jasem Mutlaq" <mutlaqja at ku.edu> wrote in message news:<9uss9d$cl6$1 at smc.vnet.net>...
> Hello. I obtained an interpolated function from a set of data representing a
> velocity curve (increasing & decreasing). I used the following
> 
> vr =Interpolation[data];
> Solve[vr[x]==0.6,x]
> 
> InverseFunction::ifun: Inverse functions are being used. Values may be lost
> for multivalued inverses.
> Out[221]={{x->1.
> InverseFunction[InterpolatingFunction[{{0.,0.95}},<>],1,1][0.6]}}
> I'm expecting something like x = 3 or x = 9 (two solutions).
> 
> Any suggestions are highly appreciated!
> 
> Jasem Mutlaq.


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