Ejemplo n.º 1
0
    def build(cls, m, wn, updater, index_over=None):
        """
        Adds a mass balance to the model for the specified junctions.

        Parameters
        ----------
        m: wntr.aml.aml.aml.Model
        wn: wntr.network.model.WaterNetworkModel
        updater: ModelUpdater
        index_over: list of str
            list of pipe names; default is all pipes in wn
        """
        if not hasattr(m, 'approx_hazen_williams_headloss'):
            m.approx_hazen_williams_headloss = aml.ConstraintDict()

        if index_over is None:
            index_over = wn.pipe_name_list

        for link_name in index_over:
            if link_name in m.approx_hazen_williams_headloss:
                del m.approx_hazen_williams_headloss[link_name]

            link = wn.get_link(link_name)
            f = m.flow[link_name]
            status = link.status

            if status == LinkStatus.Closed or link._is_isolated:
                con = aml.Constraint(f)
            else:
                eps = 1e-5  # Need to provide an options for this
                start_node_name = link.start_node_name
                end_node_name = link.end_node_name
                start_node = wn.get_node(start_node_name)
                end_node = wn.get_node(end_node_name)
                if isinstance(start_node, wntr.network.Junction):
                    start_h = m.head[start_node_name]
                else:
                    start_h = m.source_head[start_node_name]
                if isinstance(end_node, wntr.network.Junction):
                    end_h = m.head[end_node_name]
                else:
                    end_h = m.source_head[end_node_name]
                k = m.hw_resistance[link_name]
                minor_k = m.minor_loss[link_name]

                con = aml.Constraint(
                    expr=-aml.sign(f) * k * aml.abs(f)**m.hw_exp -
                    eps * k**0.5 * f -
                    aml.sign(f) * minor_k * f**m.hw_minor_exp + start_h -
                    end_h)

            m.approx_hazen_williams_headloss[link_name] = con

            updater.add(link, 'status',
                        approx_hazen_williams_headloss_constraint.update)
            updater.add(link, '_is_isolated',
                        approx_hazen_williams_headloss_constraint.update)
Ejemplo n.º 2
0
    def build(cls, m, wn, updater, index_over=None):
        """
        Adds a mass balance to the model for the specified junctions.

        Parameters
        ----------
        m: wntr.aml.aml.aml.Model
        wn: wntr.network.model.WaterNetworkModel
        updater: ModelUpdater
        index_over: list of str
            list of pipe names; default is all pipes in wn
        """
        if not hasattr(m, 'piecewise_hazen_williams_headloss'):
            m.piecewise_hazen_williams_headloss = aml.ConstraintDict()

        if index_over is None:
            index_over = wn.pipe_name_list

        for link_name in index_over:
            if link_name in m.piecewise_hazen_williams_headloss:
                del m.piecewise_hazen_williams_headloss[link_name]

            link = wn.get_link(link_name)
            f = m.flow[link_name]
            status = link.status

            if status == LinkStatus.Closed or link._is_isolated:
                con = aml.Constraint(f)
            else:
                start_node_name = link.start_node_name
                end_node_name = link.end_node_name
                start_node = wn.get_node(start_node_name)
                end_node = wn.get_node(end_node_name)
                if isinstance(start_node, wntr.network.Junction):
                    start_h = m.head[start_node_name]
                else:
                    start_h = m.source_head[start_node_name]
                if isinstance(end_node, wntr.network.Junction):
                    end_h = m.head[end_node_name]
                else:
                    end_h = m.source_head[end_node_name]
                k = m.hw_resistance[link_name]
                minor_k = m.minor_loss[link_name]
                a = m.hw_a
                b = m.hw_b
                c = m.hw_c
                d = m.hw_d

                con = aml.ConditionalExpression()
                con.add_condition(
                    aml.inequality(body=aml.abs(f),
                                   ub=m.hw_q1), -k * m.hw_m * f -
                    aml.sign(f) * minor_k * f**m.hw_minor_exp + start_h -
                    end_h)
                con.add_condition(
                    aml.inequality(body=aml.abs(f), ub=m.hw_q2),
                    -k * (a * f**3 + aml.sign(f) * b * f**2 + c * f +
                          aml.sign(f) * d) -
                    aml.sign(f) * minor_k * f**m.hw_minor_exp + start_h -
                    end_h)
                con.add_final_expr(-aml.sign(f) * k * aml.abs(f)**m.hw_exp -
                                   aml.sign(f) * minor_k * f**m.hw_minor_exp +
                                   start_h - end_h)
                con = aml.Constraint(con)

            m.piecewise_hazen_williams_headloss[link_name] = con

            updater.add(link, 'status',
                        piecewise_hazen_williams_headloss_constraint.update)
            updater.add(link, '_is_isolated',
                        piecewise_hazen_williams_headloss_constraint.update)