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Re: Problem with NMaximize

  • To: mathgroup at smc.vnet.net
  • Subject: [mg90045] Re: Problem with NMaximize
  • From: DrMajorBob <drmajorbob at att.net>
  • Date: Fri, 27 Jun 2008 06:16:37 -0400 (EDT)
  • References: <g3vkvi$kio$1@smc.vnet.net> <4863CA88.5040100@gmail.com>
  • Reply-to: drmajorbob at longhorns.com

For instance,

likelihood1[t1_?NumberQ, t2_?NumberQ, t3_?NumberQ, t4_?NumberQ,
    t5_?NumberQ, t6_?NumberQ, t7_?NumberQ, t8_?NumberQ, t9_?NumberQ,
    t10_?NumberQ, t11_?NumberQ, t12_?NumberQ] =
   0.00001712341312000713` t1 + 5.648647024829866`*^-6 t10 +
    8.90597537441381`*^-6 t11 + 1.9727284288726167`*^-6 t12 +
    4.102725237468317`*^-6 t2 + 3.7864902508468615`*^-6 t3 +
    9.215772325326653`*^-7 t4 + 0.000057161484895917856` t5 +
    0.000012892953334779516` t6 + 8.646320198720343`*^-6 t7 +
    5.877910295858781`*^-6 t8 + 1.6837835562631724`*^-6 t9;
Sort@Cases[%, a_ b_Real :> {b, a}, 1]

{{9.21577*10^-7, t4}, {1.68378*10^-6, t9}, {1.97273*10^-6,
   t12}, {3.78649*10^-6, t3}, {4.10273*10^-6, t2}, {5.64865*10^-6,
   t10}, {5.87791*10^-6, t8}, {8.64632*10^-6, t7}, {8.90598*10^-6,
   t11}, {0.000012893, t6}, {0.0000171234, t1}, {0.0000571615, t5}}

NMaximize[{likelihood1[t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11,
    t12], t1 > 0, t2 > 0, t3 > 0, t4 > 0, t5 > 0, t6 > 0, t7 > 0,
   t8 > 0, t9 > 0, t10 > 0, t11 > 0, t12 > 0,
   t1 + t10 + t11 + t12 + t2 + t3 + t4 + t5 + t6 + t7 + t8 + t9 ==
    1}, {t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12}]

{0.0000571615, {t1 -> -2.73483*10^-8, t10 -> 0., t11 -> 0., t12 -> 0.,
    t2 -> 0., t3 -> 0., t4 -> 0., t5 -> 1., t6 -> 0., t7 -> 0.,
   t8 -> 0., t9 -> 0.}}

Notice the only non-zero t value, t5, is the one with the largest  
coefficient.

And that figures, doesn't it?

Bobby

On Thu, 26 Jun 2008 13:45:57 -0500, ramiro <ramiro.barrantes at uvm.edu>  
wrote:

> Thank you very much for your responses, Bobby and Jean-Marc.   I did try  
> changing the parametrization (thanks Bobby!) and I got an answer.  
> However, let me try again with a hopefully more clear example, as I  
> don't understand why this doesn't work, in particular, I don't  
> understand why is it evaluating negative numbers if I am putting as a  
> constraint that it shouldn't?
>
>
> Sample likelihood,
>
> In[196]:=
> logLikelihood1[t1_?NumberQ, t2_?NumberQ, t3_?NumberQ, t4_?NumberQ,
>    t5_?NumberQ, t6_?NumberQ, t7_?NumberQ, t8_?NumberQ, t9_?NumberQ,
>    t10_?NumberQ, t11_?NumberQ, t12_?NumberQ] :=
>   Log[0.00001712341312000713` t1 + 5.648647024829866`*^-6 t10 +
>     8.90597537441381`*^-6 t11 + 1.9727284288726167`*^-6 t12 +
>     4.102725237468317`*^-6 t2 + 3.7864902508468615`*^-6 t3 +
>     9.215772325326653`*^-7 t4 + 0.000057161484895917856` t5 +
>     0.000012892953334779516` t6 + 8.646320198720343`*^-6 t7 +
>     5.877910295858781`*^-6 t8 + 1.6837835562631724`*^-6 t9];
>
> Another version (without the NumberQ)...
>
> In[197]:=
> logLikelihood2[t1_, t2_, t3_, t4_, t5_, t6_, t7_, t8_, t9_, t10_,
>    t11_, t12_] :=
>   Log[0.00001712341312000713` t1 + 5.648647024829866`*^-6 t10 +
>     8.90597537441381`*^-6 t11 + 1.9727284288726167`*^-6 t12 +
>     4.102725237468317`*^-6 t2 + 3.7864902508468615`*^-6 t3 +
>     9.215772325326653`*^-7 t4 + 0.000057161484895917856` t5 +
>     0.000012892953334779516` t6 + 8.646320198720343`*^-6 t7 +
>     5.877910295858781`*^-6 t8 + 1.6837835562631724`*^-6 t9];
>
> In[198]:= NMaximize[{logLikelihood1[t1, t2, t3, t4, t5, t6, t7, t8,
>    t9, t10, t11, t12], t1 > 0, t2 > 0, t3 > 0, t4 > 0, t5 > 0, t6 > 0,
>    t7 > 0, t8 > 0, t9 > 0, t10 > 0, t11 > 0, t12 > 0,
>   t1 + t10 + t11 + t12 + t2 + t3 + t4 + t5 + t6 + t7 + t8 + t9 ==
>    1}, {t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12}]
>
> During evaluation of In[198]:= NMaximize::nrnum: The function value \
> 15.7729-3.14159 I is not a real number at \
> {t1,t10,t11,t12,t2,t3,t4,t5,t6,t7,<<2>>} = {-0.490249,<<9>>,<<2>>}. \
>  >>
>
> Out[198]= {-13.2945, {t1 -> 2.10942*10^-15, t10 -> -2.22045*10^-16,
>   t11 -> -2.22045*10^-16, t12 -> -2.22045*10^-16,
>   t2 -> -1.11022*10^-16, t3 -> -2.22045*10^-16, t4 -> -2.22045*10^-16,
>    t5 -> -6.93889*10^-18, t6 -> -2.22045*10^-16,
>   t7 -> -1.11022*10^-16, t8 -> -4.44089*10^-16, t9 -> 1.}}
>
> In[199]:= NMaximize[{logLikelihood2[t1, t2, t3, t4, t5, t6, t7, t8,
>    t9, t10, t11, t12], t1 > 0, t2 > 0, t3 > 0, t4 > 0, t5 > 0, t6 > 0,
>    t7 > 0, t8 > 0, t9 > 0, t10 > 0, t11 > 0, t12 > 0,
>   t1 + t2 + t3 + t4 + t5 + t6 + t7 + t8 + t9 + t10 + t11 + t12 ==
>    1}, {t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12}]
>
> During evaluation of In[199]:= NMaximize::nrnum: The function value \
> 15.7729-3.14159 I is not a real number at \
> {t1,t10,t11,t12,t2,t3,t4,t5,t6,t7,<<2>>} = {-0.490249,<<9>>,<<2>>}. \
>  >>
>
> Out[199]= {-13.2945, {t1 -> 2.10942*10^-15, t10 -> -2.22045*10^-16,
>   t11 -> -2.22045*10^-16, t12 -> -2.22045*10^-16,
>   t2 -> -1.11022*10^-16, t3 -> -2.22045*10^-16, t4 -> -2.22045*10^-16,
>    t5 -> -6.93889*10^-18, t6 -> -2.22045*10^-16,
>   t7 -> -1.11022*10^-16, t8 -> -4.44089*10^-16, t9 -> 1.}}
>



-- 
DrMajorBob at longhorns.com


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