• Re: Scipy curve_fit

    From Stefan Ram@21:1/5 to Jorge Conrado Conforte on Sun Mar 9 14:05:35 2025
    Jorge Conrado Conforte <jc2conforte@gmail.com> wrote or quoted: >OptimizeWarning: Covariance of the parameters could not be estimated
    Please how can I resolve this error.

    The OptimizeWarning you're running into isn't a full-blown error,
    but a heads-up that the covariance of the parameters couldn't be
    nailed down. This often crops up when the fit's all over the map or
    when there's something fishy with the model or data. To get around
    this and up your curve fitting game, give these tricks a whirl:

    1. Throw in some initial parameter guesstimates:

    # Tweak the number and values of initial guesses based on your model
    popt, _ = curve_fit(non_linear_model, preciamz, areaqamz, p0=[1, 1, 1])

    . 2. Set some guardrails for your parameters if you've got a ballpark
    idea of where they should land:

    # Adjust bounds based on your model and data
    popt, _ = curve_fit(non_linear_model, preciamz, areaqamz,
    bounds=([0, 0, 0], [100, 100, 100]))

    . 3. Make sure your `non_linear_model` function is on point and
    coughs up values for all input data:

    # Example function, tweak based on your specific model
    def non_linear_model(x, a, b, c):
    return a * np.exp(-b * x) + c

    . 4. Give your data a once-over for any oddball points or
    inconsistencies that might throw a wrench in the works.

    5. If you're still hitting a wall, try a different optimization
    method:

    popt, _ = curve_fit(non_linear_model, preciamz, areaqamz, method='trf')

    . 6. Think about using the lmfit library for more bells and whistles
    in fitting options and better handling of parameter uncertainties.

    If you're still stuck, double-check your model and data
    to make sure they're suitable for curve fitting. Keep in mind
    that curve_fit assumes continuous variables, so discrete or
    step-like data might gum up the works.

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