The Complete SPRLIB & ANNLIB

derf_bfgs: - compute the derivative of the objective function as needed by the BFGS method (LOCAL)

void derf_bfgs

(p, df)

`double`	*`p`**	Vector containing the current weight values.
`double`	*`df`**	Gradient of the MSE of the net and data set under investigation; computed using `grad_net_mse`.

Nothing; the derivative is calculated and returned through df.

`derf_bfgs`