What is causing the NMinimize error in my Mathematica calculation?

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Discussion Overview

The discussion revolves around an error encountered in a Mathematica calculation using the NMinimize function. Participants explore the nature of the error and the variables involved in the calculation, focusing on the function definition and the input data.

Discussion Character

  • Technical explanation

Main Points Raised

  • One participant reports an error message from NMinimize indicating that the function value is not a number at specific input values.
  • The same participant shares their code for the function XDDO154, which involves a summation of squared differences and uses several input tables.
  • Another participant asks for clarification on the contents of the tables DDO154vobs, DDO154pc, and DDO154err.
  • The original poster responds that the tables consist of one column with numerical values representing velocity, distance, and errors.
  • The original poster later indicates that the issue was due to a problem with their table, suggesting that the error was resolved.

Areas of Agreement / Disagreement

The discussion appears to be resolved as the original poster identifies the source of the error in their data tables, indicating a lack of ongoing disagreement.

gaby287
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What wrong with my calculation.the problem is from the attachment.
It keeps saying:
NMinimize::nnum: "The function value {10721.1} is not a number at {rs,x} = {1.91862,1.66351}. "

My code:

XDDO154[x_, rs_] :=
Sum[(DDO154vobs[] -
Sqrt[(4 Pi*(43.040600502)*x*
rs^(3)/(DDO154pc[]))*(-DDO154pc[]/(DDO154pc[] +
rs) + Log[((DDO154pc[] + rs)/rs)])])^2/
DDO154err[], {i, 1, 61}]

NMinimize[{XDDO154[x, rs], 0 < x && 0 < rs}, {x, rs}, Method -> "DifferentialEvolution"]

(DDO1254pc, DDO154err are tables)
 
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What do DDO154vobs, DDO154pc, and DDO154err look like?
 
They are tables of one column with numbers, like velocity, distance and errors.
 
Forget it¡ Something was wrong with my table. Thanks¡
 

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