Hessian Diagonal

Estimate the diagonal of the Hessian of a scalar function: the second derivative along each coordinate axis.

Implement solve(f, x, h=1e-5).

Returns. Return a NumPy array of length $nn$. The values are finite-difference estimates, accurate to roughly three decimals.

Examples

Example 1

Input:

solve(lambda z: float(np.sum(z**2)), [1.0, 2.0])

Output:

[2.0, 2.0]

Example 2

Input:

solve(lambda z: float(np.sum(z**3)), [1.0, 2.0])

Output:

[6.0, 12.0]