Basic 1D Fit

This tutorial walks through the essential steps to perform a basic 1D fit using the Graphical Curve Fit for Python application. It is designed for first-time users to become familiar with the core workflow: loading data, defining a model, fitting, and analyzing the results.

Step 1 – Load Example Data

  1. Launch the application: bash gcfpy
  2. Go to File > Load Data
  3. Select the file: examples/data/linear.csv
  4. Two docks will appear:
  5. X/Y Data: showing the raw data
  6. Fit Control: tools to launch and manage fits

data

Step 2 – Enter a Fit Formula

A formula is automatically added to the fit formula dock:

y = a * x + b

The application automatically extracts the parameters (a, b) and sets them up for fitting.

You may also use built-in functions like sin, exp, log, and physical constants such as pi, e, h, etc.

Step 3 – Configure Fit Options (Optional)

Open the Fit Options dialog if you want to:

  • Set initial guesses for a and b
  • Define bounds
  • Choose a different optimizer (default is leastsq)

This step is optional – default values will work for most basic examples.

Step 4 – Run the Fit

Press the Run Fit button in the Fit Control dock

Upon completion, the following are updated:

  • Results Dock: fitted values, standard errors, and metrics (AIC, BIC, RMSE, etc.)
  • Plot: displays the best-fit line

fit