Multiplier for inequality constraints

def factor_aug(z, DPhival, G, A):    
    M, N = G.shape
    P, N = A.shape
    """Multiplier for inequality constraints"""
    l = z[N+P:N+P+M]

    """Slacks"""
    s = z[N+P+M:]

    """Sigma matrix"""
    SIG = diags(l/s, 0)

    """Condensed system"""
    if issparse(DPhival):
        if not issparse(A):
            A = csr_matrix(A)        
        H = DPhival + mydot(G.T, mydot(SIG, G))
        J = bmat([[H, A.T], [A, None]])
    else:
        if issparse(A):
            A = A.toarray()
        J = np.zeros((N+P, N+P))
        J[0:N, 0:N] = DPhival + mydot(G.T, mydot(SIG, G))            
        J[0:N, N:] = A.T
        J[N:, 0:N] = A

    LU = myfactor(J)    
    return LU