tools.py

        if gt(G.x * G.y * G.z, 0):
            # Procedure A3
            i = 2 * gt(G.x, 0) - 1
            j = 2 * gt(G.y, 0) - 1
            k = 2 * gt(G.z, 0) - 1
#            i = -1 if G.x < -G.epsilon else 1
#            j = -1 if G.y < -G.epsilon else 1
#            k = -1 if G.z < -G.epsilon else 1
        else:
            # Procedure A4
            i = 2 * lt(G.x, 0) - 1
            j = 2 * lt(G.y, 0) - 1
            k = 2 * lt(G.z, 0) - 1
#            i = -1 if 0 < G.x - G.epsilon else 1
#            j = -1 if 0 < G.y - G.epsilon else 1
#            k = -1 if 0 < G.z - G.epsilon else 1