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FindRoot migration question

  • To: mathgroup at smc.vnet.net
  • Subject: [mg79904] FindRoot migration question
  • From: "Guillermo Barrenetxea" <ilargia at gmail.com>
  • Date: Wed, 8 Aug 2007 04:55:43 -0400 (EDT)

Hi,

I have recently migrated form mathematica 4 to mathematica 6, and some of
the programs I was using are not correct any more.
One recurrent error occurs with functions including FindRoot. I enclose here
an example:

thanks for your help,
guillermo




quit;
cmin = 10^(-10); cmax = 1/100;
sigma1[n1_, nx_, cov_, L_] := (4 Pi^2 L^2 nx (1 - n1))/(Log[1/cov] - ((3 -
cov) (1 - cov)/2))
LL1[nx_, cov_] := FindRoot[nx L^2 Pi (Log[L^2 Pi] - (1 - (1/(Pi L^2)))) ==
Log[1/cov] - (1 - cov), {L, 1.0, 2.0}]
sigm1[n1_, nx_, cov_] := sigma1[n1, nx, cov, L /. LL1[nx, cov]]

sigm1[1/10000000000, 1/10000000000, 1/10000000000]  (* this works perfectly
*)


(* however, if I want to interpolate the sim1 function, it complains  *)

sig1 = FunctionInterpolation[sigm1[n1, nx, cov], {n1, cmin, cmax}, {nx,
cmin, cmax}, {cov, cmin,cmax}];



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