# Thread Subject: Equation solution with constrains

 Subject: Equation solution with constrains From: Javier Date: 19 Sep, 2011 15:03:28 Message: 1 of 4 Hi, I have a nonlinear system of 4 equations with 4 unknowns like: y1 = f(x1,x2,x3,x4) = 0; y2 = f(x1,x2,x3,x4) = 0; y3 = f(x1,x2,x3,x4) = 0; y4 = f(x1,x2,x3,x4) = 0; But I have 4 boundaries: x1-4 are inside [-2e-2, 2e-2] I want to find the x1-4 inside these boundaries that make y1-4 = 0 or at least that minimises them below 1e-13. Can I put these constraint in fsolve? Should I use another function? Thanks.
 Subject: Equation solution with constrains From: Matt J Date: 19 Sep, 2011 15:19:28 Message: 2 of 4 "Javier" wrote in message ... > > > Can I put these constraint in fsolve? Should I use another function? See LSQNONLIN
 Subject: Equation solution with constrains From: Greg Heath Date: 19 Sep, 2011 23:17:00 Message: 3 of 4 On Sep 19, 11:03 am, "Javier " wrote: > Hi, > > I have a nonlinear system of 4 equations with 4 unknowns like: > > y1 = f(x1,x2,x3,x4) = 0; > y2 = f(x1,x2,x3,x4) = 0; > y3 = f(x1,x2,x3,x4) = 0; > y4 = f(x1,x2,x3,x4) = 0; > > But I have 4 boundaries: x1-4 are inside [-2e-2, 2e-2] > I want to find the x1-4 inside these boundaries that make y1-4 = 0 or at least that minimises them below 1e-13. > > Can I put these constraint in fsolve? Should I use another function? > > Thanks. Did you mean to use 4 different functions f1,f2,f3 and f4? Hope this helps. Greg
 Subject: Equation solution with constrains From: Javier Date: 20 Sep, 2011 08:04:30 Message: 4 of 4 Greg Heath wrote in message ... > On Sep 19, 11:03 am, "Javier " wrote: > > Hi, > > > > I have a nonlinear system of 4 equations with 4 unknowns like: > > > > y1 = f(x1,x2,x3,x4) = 0; > > y2 = f(x1,x2,x3,x4) = 0; > > y3 = f(x1,x2,x3,x4) = 0; > > y4 = f(x1,x2,x3,x4) = 0; > > > > But I have 4 boundaries: x1-4 are inside [-2e-2, 2e-2] > > I want to find the x1-4 inside these boundaries that make y1-4 = 0 or at least that minimises them below 1e-13. > > > > Can I put these constraint in fsolve? Should I use another function? > > > > Thanks. > > Did you mean to use 4 different functions f1,f2,f3 and f4? > > Hope this helps. > > Greg Yes, I didn't write that clear, but I have different f1 to f4 functions.

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