(For some reason, plt.bar was used instead of plt.plot, so the y axis would start at 0 by default, making all results look the same. But when the log scale is applied, the lower y limit becomes the data’s minimum. So, because the dynamic range is so low, the end result is visually identical to having just set y limits using the original linear scale).

Anyhow for anyone interested the values for those 3 points are 2.0000 (exact), 1.9671 (trapezoid), and 1.9998 (gaussian). The relatives errors are 1.6% vs. 0.01%.