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Re: squared norm in Mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg85778] Re: [mg85764] squared norm in Mathematica
  • From: Curtis Osterhoudt <cfo at lanl.gov>
  • Date: Fri, 22 Feb 2008 04:58:48 -0500 (EST)
  • Organization: LANL
  • References: <200802212302.SAA18356@smc.vnet.net>
  • Reply-to: cfo at lanl.gov

  Hi, Syed,

       Though I can't necessarily read your FindMinimum command (it seems to
contain some non-standard characters), I think I see what the problem is.
That error message almost always crops up when you've tried to assign a value
to something which isn't allowed to be assigned to.
    In other words, I suspect you have to replace the single equals sign ( = )
in "-4+x12+x22+x32+x42=0"  with a double one ( == ).

                    I hope that helps!
                            C.O.


On Thursday 21 February 2008 16:02:29 syed qasim Ali wrote:
>   Dear Sir,
>   My problem was  actually
>
>   ||SX||^2
>
>   i was trying it as multiobjective optimiztaion in Mathematica but i got
> to know that it can be programmed as single objective ....
>
>   ||SX||^2=(a11*x1 + a12*x2 + a13*x3)^2 + (a21*x1 + a22*x2 +
>
> a23*x3)^2 + (a31*x1 + a32*x2 + a33*x3)^2.
>
>
>   therefore my problem becomes
>
>    x1 >= 0.52, <= 1.47;
>  x2 >= 0.52, <= 1.47;
>  x3 >= 0.52, <= 1.47;
>  x4 >= 0.52, <= 1.47;
>
>
>
>   minimize : ( ((-0.22*x1)+(0.13*x2)+(-0.09*x3)+(0.07*x4))^2 +
> ((-0.13*x1)+(0.09*x2)+(-0.07*x3)+(0.058*x4))^2 +((-0.09*x1)+(0.07*x2)+
> (-0.058*x3)+(0.049*x4))^2);
>
>
> subject to:
>           -4+x1^2+x2^2+x3^2+x4^2=0;
>
>
>   IN Mathematica it becomes
>
>   FindMinimum[{(-0.22 g1+0.13 g2-0.09 g3+0.07 g4)2+(-0.13 x1+0.09 x2-0.07
> x3+0.058 x4)2+(-0.09 x1+0.07 x2-0.058 x3+0.049
> x4)2,-4+x12+x22+x32+x42=0&&0.52=A3x1=A31.47,0.52=A3x2=A31.47,0.52=A3x3=A31.47,0.5
>2=A3x4=A31.47},{x1,x2,x3,x4}]
>
>
>   i have this  result when i tried this problem in Mathematica ....i guess
> Mathematica can handle this problem
>
>   Set::write : Tag Plus in
>   -4+x12+x22+x32+x42 is Protected
>   FindMinimum::eqineq : Constraints in
> {0,0.52=A3x1,0.52=A3x2,0.52=A3x3,0.52=A3x4,x1=A31.47,x2=A31.47,x3=A31.47,x4=A31.47}
> are not all equality or inequality constraints. With the exception of
> integer domain constraints for linear programming, domain constraints or
> constraints with Unequal (!=) are not supported.
>
>   i donot understand where the fault lies ...when i have only one objective
> function
>
>
>   thanx



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Curtis Osterhoudt
cfo at remove_this.lanl.and_this.gov
PGP Key ID: 0x4DCA2A10
Please avoid sending me Word or PowerPoint attachments
See http://www.gnu.org/philosophy/no-word-attachments.html
==========================
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