Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Fminsearch- Matlab help

  1. Jul 27, 2009 #1
    Hi there,

    I am getting confused trying to use fminsearch. I have looked at the help on Matlab but can't seem to understand how to get it to work.

    I would like to find the minimum chi squared values of two parameters H and omega. I have written a function that will find the min chi squared value of H keeping omega constant, and thought that I could put this into a loop for varying values of omega, so find best H value for each value of omega. Could I use fminsearch instead to find the best fit of both values at once?
    I am confused about what I need to do and any help would be greatly appreciated.

    Many thanks
  2. jcsd
  3. Jul 29, 2009 #2


    User Avatar
    Science Advisor
    Gold Member

    Sure, you can use fminsearch to find where the function is a minimum, but it will not necessarily be a global minimum - fminsearch can get stuck in a local minimum so your answer will depend on your initial conditions. I'm not sure what information I can provide outside of MATLAB's help - I assume you know how to define a function. Without using any of the options, fminsearch takes a function and an initial condition vector as inputs (yours is a function of 2 variables, so xo [the initial condition] will be a vector).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook