I have been generating some figures for some profile measurements; however, I am finding that the flatness does not seem to work for “smaller” field sizes.

It works perfectly fine for larger than 10x10, just not for smaller field sizes (such as a 10x10 electron field).

Update: As shown in the plot, the lower value for tthe flatness is incorrect as it should reside on the profile. The result in getting is 14% (it should be less than 1%).

Any thoughts?

Some of my code below (taken from an excel file).

df = pd.read_csv('{}/{}.csv'.format(path, fn))
# Convert the Dataframe into a numpy array
a = df.to_numpy()
# Create the profile data using PyLinac functions (FFF)
profile1 = InflectionDerivativeProfilePhysical(values = a[:,1], x_values = a[:,0])
profile1.compute(metrics=[FlatnessDifferenceMetric(in_field_ratio=0.2)])
# Extra small field ratio to show the confusion

I do not understand what your Question actually is. What results do you get for your Flatness? Did you compare the pylinac results to calculations done by hand? According to the plot I would assume the Flatness is excellent?
Formula: Profiles & 1D Metrics - pylinac 3.28.0 documentation

Hi,
I tested with some watertank scans of a 4x4 field. I don’t get the same results from pylinac compared to a calculation without pylinac but I get resonable results (1.64 with pylinac and 1.48 when doing the calculation “by hand”).
I tested with pylinac 3.28 and 3.25
I also see no difference between in_field_ratios of 0.8 and 0.2.

What happens if you don’t give x_values and instead use the dpmm option?