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From |
Austin Nichols <[email protected]> |

To |
[email protected] |

Subject |
Re: st: Optimize |

Date |
Mon, 23 Jul 2012 10:25:57 -0400 |

Mohamud Hussein <[email protected]>: Looks like you are trying to maximize the unbounded quadratic rather than find its zeros. Use a root finder instead e.g. http://www.stata.com/statalist/archive/2007-12/msg00551.html http://www.stata.com/statalist/archive/2009-01/msg01140.html but note first that the particular example you gave has no zeros (so no interior solution). On Sun, Jul 22, 2012 at 9:59 AM, Mohamud Hussein <[email protected]> wrote: > Hi there, > > I am trying to run a model for a marginal cost curve equation based on the traditional cubic total cost curve function (i.e. y= x^3+X^2+X+c) using Stata's optimize() command. The goal is to estimate the value of x which minimises y subject to a number of constraints. > > When I tried to specify the marginal cost curve function in mata directly as y=3x^2+2x+1 (i.e. first derivative of the total cost equation) I got the following message: > > Iteration 0: f(p) = 1 (not concave) > Iteration 1: f(p) = 7.911e+71 (not concave) > Iteration 2: f(p) = 1.95e+169 (not concave) > Iteration 3: f(p) = 8.32e+250 (not concave) > Iteration 4: f(p) = 1.62e+288 (not concave) > Iteration 5: f(p) = 2.34e+306 > Hessian is not negative semidefinite > > I have never used Stata's mata programming language before and am not quite sure of what do here? Grateful if someone can help me on this. > > Thanks, > Mohamud * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**RE: st: Optimize***From:*Mohamud Hussein <[email protected]>

**References**:**st: Optimize***From:*Mohamud Hussein <[email protected]>

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