Re: problem with FindRoot

*To*: mathgroup at smc.vnet.net*Subject*: [mg54066] Re: [mg54035] problem with FindRoot*From*: "Janos D. Pinter" <jdpinter at hfx.eastlink.ca>*Date*: Wed, 9 Feb 2005 09:27:49 -0500 (EST)*References*: <200502081031.FAA17745@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Mr/Ms qfwfq, You can write y1<=y2<=y3<=y4 as separate constraints (notice the <= relations). Then use the built-in function NMInimize with the modified constraints, or the [commercial] packages MathOptimizer / Pro. Regards, Janos D. Pinter, PhD, DSc President & Research Scientist, PCS Inc. Adjunct Professor, Dalhousie University, Halifax, NS, Canada Research Fellow, University of Ballarat, Vic., Australia 129 Glenforest Drive, Halifax, NS, Canada B3M 1J2 Telephone: +1-(902)-443-5910 Fax: +1-(902)-431-5100; +1-(902)-443-5910 E-mail: jdpinter at hfx.eastlink.ca Web: www.pinterconsulting.com www.dal.ca/~jdpinter Software products: http://www.pinterconsulting.com/Software_Sum_Info.pdf At 06:31 AM 2/8/2005, qfwfq wrote: >Hi all! > >I have four equations (eq1=0, ..., eq4=0) with the the four unknowns >(y1, y2, y3, y4) in exponentials. I know the interval where the >solutions are, and I solve this equation set by means of FindRoot by >obtaining set of solutions. Then, I make a selection between the >obtained results. > >However, I have a dependency between variables: y1<y2<y3<y4 > > >mR = Table[FindRoot[{eqn1 == 0, eqn2 == 0, eqn3 == 0, eqn4 == 0}, {y1, >Random[Real, {a, b}]}, {y2, Random[Real, {a, b}]}, {y3, Random[Real, >{a, b}]}, {y4, Random[Real, {a, b}]}], {24}]; > >My question is > >Is there any way of include the relation between y1, ..., y4 in the >selection of them by Random. Something like {y2, Random[Real, {y1, >b}]}, {y3, Random[Real, {y2, b}]}, ... > >I hope I have clearly explained my problem. > >Thanks

**References**:**problem with FindRoot***From:*"qfwfq" <qfwfq_0@yahoo.com>