This error occurs when trying to plot data using Matplotlib, and the x and y arrays have different lengths. In this specific case, the x array has a length of 1048576, while the y array has a length of 1048575.
To fix this error, you need to ensure that the x and y arrays have the same length. One way to do this is to truncate the longer array to match the length of the shorter array. For example, you can modify the code to:
```
t = t[:len(composite_index)]
ax1.plot(t, composite_index, color=color)
```
This will truncate the t array to match the length of the composite_index array, ensuring that both arrays have the same length and can be plotted together.