  We explain how to compute gradients of functions of the form $G = \frac{1}{2}
\sum_{i=1}^{m} (E y_i - C_i)^2$, which often appear in the calibration of
stochastic models, using Automatic Adjoint Differentiation and parallelization.
We expand on the work of arXiv:1901.04200 and give faster and easier to
implement approaches. We also provide an implementation of our methods and
apply the technique to calibrate European options.
