Re: FindMinimum

*To*: mathgroup at smc.vnet.net*Subject*: [mg15866] Re: FindMinimum*From*: "Hossein Kazemi" <kazemi at som.umass.edu>*Date*: Fri, 12 Feb 1999 18:40:27 -0500 (EST)*Organization*: University of Massachusetts, Amherst*References*: <79m6o0$3at@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Sorry, I just noticed an error in my presentation of the problem. The correct for is: f=Sign[4.35x-13.57y +Sqrt[1-x^2-y^2]] - Sign[2.49x-11.18y+ Sqrt[1-x^2-y^2]]+... Hossein Kazemi wrote in message <79m6o0$3at at smc.vnet.net>... >I have an expression that involves the Sign[] function. For example, >consider > >f=Sign[4.35x-13.57y +(1-x^2-y^2)]-Sign[2.49x-11.18y+(1-x^2-y^2)]+... > >I need to find the minimum of this function. Since the symbolic >derivatives with respect to x and y do not exist, I have to use > >FindMinimum[f,{x,{x0,x1}},{y,{y0,y1}}] > >But this does not restrict Mathematica not look outside (-1,1) range for >solutions, >where (1 - x^2 - y^2) will not be real. > >Is there anyway to find the minimum of a function when symbolic >derivatives of >the function do not exist and values outside a range should not be used. > >Thank you. >kazemi at som.umass.edi > > >