f_df_drsc

Function value and derivative with respect to last projection vector (column) of W
[F, DF] = F_DF_DRSC(DATA, W, SIGMA, U, DEGS)

 Inputs:
    (DATA): N-by-D data matrix
    (W): Projection matrix
    (SIGMA): scale parameter for Gaussian kernel used to 
        estimate similarity matrix (K)
    (U): First (K) eigenvectors of D^{-1/2} *K*D^{-1/2}
    (DEGS): Vector of degrees of each vertex: D = diag(degs)

 Output:
    (F): Function value
    (DF): Derivative