RE: Problems with FindMinimum

*To*: mathgroup at smc.vnet.net*Subject*: [mg90738] RE: Problems with FindMinimum*From*: "Teodoro Marinucci" <teodorom at hotmail.com>*Date*: Tue, 22 Jul 2008 03:57:11 -0400 (EDT)*References*: <g5v5mf$ia9$1@smc.vnet.net> <488371B2.3020604@gmail.com>

Merci Jean-Marc, unfortunately the exponential (Z0 in the following) is 3/2, not 2/3. When one is lucky ... because in the most general case the exponential is a real number (between 1 and 1.5). The function I'm trying to fit with the experimental data (that are supplied in Vgk[[i]] and Vak[[i]]) is is[Vgk_,Vak_,Z0_,G0_,G1_,G2_, G3_,mu0_,mu1_,mu2_,mu3_,H0_,H1_,H2_,H3_]:=(G0+G1 Vgk+G2 Vgk^2+G3 Vgk^3 ) (Vgk+Vak/(mu0+mu1 Vgk+mu2 Vgk^2+mu3 Vgk^3)+H0+H1 Vgk+H2 Vgk^2+H3 Vgk^3)^Z0 It has a lot of parameters, I know, but usually G0>>G1>>G2>>G3 and so on, so I could, in principle, attempt a perturbative approach. Unfortunately I get the same error even if I start from a enough good solution (enough near fit). Thanks again Teodoro Marinucci -----Original Message----- From: Jean-Marc Gulliet [mailto:jeanmarc.gulliet at gmail.com] Sent: domenica 20 luglio 2008 19.11 To: teodorom at hotmail.com; mathgroup at smc.vnet.net Subject: [mg90738] Re: Problems with FindMinimum teodorom at hotmail.com wrote: > I'm having problems with the FindMinimum. > I'm currently getting errors like this: > FindMinimum::nrlnum: The function value {0.335521+43899.8 \ > [ImaginaryI],0.376043+43899.8 \[ImaginaryI],0.424669+43899.8 \ > [ImaginaryI],<<6>>,0.311208+46311.9 \[ImaginaryI],<<27>>} is not a > list of real numbers with dimensions {37} at {x0,y0,x1,y1,hh0,hh1} > {0.00580647,-2.13969*10^20,-9.86301*10^-6,1.23875*10^20,-30574.3,19.6042}