Messages from Usenet group comp.lang.idl-pvwave, compiled by Paulo Penteado
Hi I have to fit a modell function to given data and thought curvefit() would be a nice tool for doing that. In order to test curvefit() I ran the examples given in the online help. And no surprise curvefit calculated the 'right' fit. However when I slightly changed one of the starting values the fit was way off. I am aware that curvefit() finds local minimae only, but for such a _simple_ example it should be able to converge to the proper fit. Did anybody encounter similar problems with curvefit(). Is there a workaround? Or is there another general fitting routine around? ( I know that there is a routine curfit() in the user_contrib/windt directory, but that one is most similar to curvefit and does not work either ). To be specific I used the example given in the online help for curvefit() under the math section. When I changed the starting value from a=[10.0,-0.1,2.0] to a=[.0,-0.1,2.0] the fit failed ..... Any help is appreciated, Andreas