Weight Decay Penalty

Compute the L2 weight-decay penalty $\lambda {\sum }_i{w}_i^2\backslash lambda\backslash sum\_i\; w\_i^2$ of a weight vector (there is no factor $\frac{1}{2}\backslash tfrac12$).

Implement solve(w,lam).

Returns. Return a non-negative float.

Examples

Example 1

Input:

solve([1.0, 2.0, 3.0], 0.1)

Output:

1.4

Example 2

Input:

solve([0.0, 0.0], 5.0)

Output:

0.0