Gradient of a Quadratic

Return the gradient of the quadratic function $f(x)=\frac{1}{2}{x}^{\mathrm{\top }}Ax+b^{\mathrm{\top }}xf(x)=\backslash tfrac12\; x^\backslash top\; A\; x+b^\backslash top\; x$. The matrix $AA$ does not have to be symmetric.

Implement solve(A, x, b).

Returns. Return a NumPy array of length $nn$.

Examples

Example 1

Input:

solve([[2.0, 0.0], [0.0, 2.0]], [1.0, 1.0], [0.0, 0.0])

Output:

[2.0, 2.0]

Example 2

Input:

solve([[0.0, 1.0], [0.0, 0.0]], [1.0, 2.0], [0.0, 0.0])

Output:

[1.0, 0.5]