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NMaximize gives wrong result

Thanasis Mnt
Posted 11 years ago

Hi, i am experiencing this issue with NMaximize function. The function returns a maximum value 0.999985, but in graph shows that the maximum is 0.999706. Does anyone knows why is this happening?

Availability
POSTED BY: Thanasis Mnt
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POSTED BY: Sean Clarke

A notebook file with all the code and information to needed to duplicate the result would be the straight-forward method.

Please include 

$Version

and its output.
POSTED BY: Bruce Miller
Thanasis Mnt
Thanasis Mnt
Posted 11 years ago

Hi again, i solved my problem including Method -> "NelderMead" to my NMaximize function and the result is rigth now.
POSTED BY: Thanasis Mnt

Sorry, I was unclear. Run Availability on the actual value returned by NMaximize.

Mathematica clips numbers when displaying them. This is so that the output stays readable. For example:

N[Pi]
3.14159

InputForm@%
3.141592653589793

InputForm shows you the actual output of a command. Try using it to see what the rest of the decimal values are in (5193.6.....)

InputForm[NMaximize[Availability[...],....]]

Is the value for Availability different when these digits are used?

I'm guessing that this difference in value is a numerical instability in the definition of Availability. Are you expecting availability to be smooth or jagged?
POSTED BY: Sean Clarke
Thanasis Mnt
Thanasis Mnt
Posted 11 years ago

NMaximize returns 0.999985 for T1 = 5193.6 Availability[5193.6] returns 0.999706 I am running now Table[Availability[T1], {T1, 8760}] to see which value is maximum
POSTED BY: Thanasis Mnt
Jim Baldwin
Jim Baldwin, Retired
Posted 11 years ago

Sorry, I should have been more specific. Given the form of your function, the complete definition is necessary. What are all of the v, h, and sumsp functions?
POSTED BY: Jim Baldwin
Thanasis Mnt
Thanasis Mnt
Posted 11 years ago 
Availability[T1_] = (v0[T1]*h0[T1] + v1[T1]*h1[T1] + v2[T1]*h2[T1] + v3[T1]*h3[T1] + v9[T1]*h9[T1] + v10[T1]*h10[T1] + v11[T1]*h11[T1] + v12[T1]*h12[T1] + v19[T1]*h19[T1] + v20[T1]*h20[T1] + v21[T1]*h21[T1] + v22[T1]*h22[T1] + v23[T1]*h23[T1] + v29[T1]*h29[T1] + v30[T1]*h30[T1] + v31[T1]*h31[T1])/sumssp[T1];
POSTED BY: Thanasis Mnt
Jim Baldwin
Jim Baldwin, Retired
Posted 11 years ago

Prior to sending in a bug report I would think that providing the definition of your function Availability would need to be supplied. Would you share the definition of that function?
POSTED BY: Jim Baldwin
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