\nabla H (x,y,z) = 
\left(
\begin{array}{ccc}
 e^x+3 x^2 \sin\left(x^3+\frac{\pi z}{2}\right) & 0 & \frac{\pi}{2} \sin}\left(x^3+\frac{\pi z}{2}\right) \\
 0 & 4 y z & 2 y^2
\end{array}
\right)