when set two flows with different periods,cant get the reult,which log the "The specified constraints MIGHT NOT be satisfiable"

[Glory-Yin]

here is the test code,which overwrites the SmallScenario.java the network is 4 devices and 6 switches and 2 flows,when flow1 send at 2ms, flow2 send at 2ms，the result is ok when flow1 send at 2ms, flow2 send at 3ms，the result is NOT be satisfiable. but i dont know why,becasue the z3 just give the final result,but which constraint is unknown.

package com.tsnsched.generated_scenarios; import java.util.; import java.io.; import com.tsnsched.core.nodes.; import com.tsnsched.core.components.Cycle; import com.tsnsched.core.components.Flow; import com.tsnsched.core.components.PathNode; import com.tsnsched.core.network.; import com.tsnsched.core.schedule_generator.*; import com.tsnsched.core.components.Port;

public class SmallScenario { public void runTestCase(){

    /*
     * GENERATING DEVICES
     */
    Device ccu = new Device(1000, 0, 1000, 1500);
    ccu.setName("ccu");

    Device ccu2 = new Device(1000, 0, 1000, 1500);
    ccu2.setName("ccu2");

    Device tcu = new Device(1000, 0, 1000, 1500);
    tcu.setName("tcu");

    Device bcu = new Device(1000, 0, 1000, 1500);
    bcu.setName("bcu");

    /*
     * GENERATING SWITCHES
     */
    TSNSwitch switch0 = new TSNSwitch("switch0", 100, 1, 125, 1, 400, 3000);
    TSNSwitch switch1 = new TSNSwitch("switch1", 100, 1, 125, 1, 400, 3000);
    TSNSwitch switch2 = new TSNSwitch("switch2", 100, 1, 125, 1, 400, 3000);
    TSNSwitch switch3 = new TSNSwitch("switch3", 100, 1, 125, 1, 400, 3000);
    TSNSwitch switch4 = new TSNSwitch("switch4", 100, 1, 125, 1, 400, 3000);
    TSNSwitch switch5 = new TSNSwitch("switch5", 100, 1, 125, 1, 400, 3000);

    /*
     * GENERATING SWITCH CONNECTION PORTS
     */
    Cycle cycle0 = new Cycle(50);
    Port port0 = switch0.createPort(switch1, cycle0);//switch0 use x11 to connect switch1 
    port0.setPortNum(11);
    port0.setName(port0.getName()+ "Port"+ "11");

    Cycle cycle1 = new Cycle(50);
    Port port1 = switch1.createPort(switch0, cycle1);
    port1.setPortNum(4);
    port1.setName(port1.getName()+ "Port"+ "4");

    Cycle cycle2 = new Cycle(50);
    Port port2 = switch1.createPort(switch2, cycle2);   
    port2.setPortNum(1);
    port2.setName(port2.getName()+ "Port"+ "1");

    Cycle cycle3 = new Cycle(50);
    Port port3 = switch2.createPort(switch1, cycle3);
    port3.setPortNum(2);
    port3.setName(port3.getName()+ "Port"+ "2");

    Cycle cycle4 = new Cycle(50);
    Port port4 = switch2.createPort(switch3, cycle4);
    port4.setPortNum(1);
    port4.setName(port4.getName()+ "Port"+ "1");

    Cycle cycle5 = new Cycle(50);
    Port port5 = switch3.createPort(switch2, cycle5);
    port5.setPortNum(2);
    port5.setName(port5.getName()+ "Port"+ "2");

    Cycle cycle6 = new Cycle(50);
    Port port6 = switch3.createPort(switch4, cycle6);
    port6.setPortNum(1);
    port6.setName(port6.getName()+ "Port"+ "1");

    Cycle cycle7 = new Cycle(50);
    Port port7 = switch4.createPort(switch3, cycle7);
    port7.setPortNum(2);
    port7.setName(port7.getName()+ "Port"+ "2");

    Cycle cycle8 = new Cycle(50);
    Port port8 = switch4.createPort(switch5, cycle8);
    port8.setPortNum(4);
    port8.setName(port8.getName()+ "Port"+ "4");

    Cycle cycle9 = new Cycle(50);
    Port port9 = switch5.createPort(switch4, cycle9);   
    port9.setPortNum(11);
    port9.setName(port9.getName()+ "Port"+ "11");

    /*
     * LINKING SWITCHES TO DEVICES
     */
    Cycle cycle10 = new Cycle(50);
    Port port10 = switch0.createPort(ccu, cycle10);
    port10.setPortNum(9);
    port10.setName(port10.getName()+ "Port"+ "9");

    Cycle cycle11 = new Cycle(50);
    Port port11 = switch5.createPort(tcu, cycle11);
    port11.setPortNum(9);
    port11.setName(port11.getName()+ "Port"+ "9");

    Cycle cycle12 = new Cycle(50);
    Port port12 = switch2.createPort(ccu2, cycle12);
    port12.setPortNum(9);
    port12.setName(port12.getName()+ "Port"+ "9");

    Cycle cycle13 = new Cycle(50);
    Port port13 = switch4.createPort(bcu, cycle13);
    port13.setPortNum(9);
    port13.setName(port13.getName()+ "Port"+ "9");

    /*
     * GENERATING FLOWS
     */
    LinkedList<PathNode> nodeList;

    Flow flow1 = new Flow(1,0,2000);
    //Flow flow1 = new Flow(Flow.UNICAST);
    flow1.setStartDevice(ccu);
    flow1.addToPath(ccu,switch0);
    flow1.addToPath(switch0,switch1);
    flow1.addToPath(switch1,switch2);
    flow1.addToPath(switch2,ccu2);
    flow1.addToPath(switch2,switch3);
    flow1.addToPath(switch3,switch4);
    flow1.addToPath(switch4,bcu);
    flow1.addToPath(switch4,switch5);
    flow1.addToPath(switch5,tcu);

    flow1.setPriorityValue(5);
    flow1.setFixedPriority(true);
    //flow1.setPacketSize(1500);
    //flow1.setFlowMaximumLatency(1000);
    flow1.setFlowSendingPeriodicity(2000);

    Flow flow2 = new Flow(1,0,2000);
    //Flow flow2 = new Flow(Flow.UNICAST);
    flow2.setStartDevice(ccu);
    flow2.addToPath(ccu,switch0);
    flow2.addToPath(switch0,switch1);
    flow2.addToPath(switch1,switch2);
    flow2.addToPath(switch2,ccu2);
    flow2.addToPath(switch2,switch3);
    flow2.addToPath(switch3,switch4);
    flow2.addToPath(switch4,bcu);
    flow2.addToPath(switch4,switch5);
    flow2.addToPath(switch5,tcu);
    flow2.setPriorityValue(5);
    flow2.setFixedPriority(true);   
    //flow2.setPacketSize(1500);
    flow2.setFlowSendingPeriodicity(2000);//when set it to 3ms，the result is not satisfied
    //flow2.setFlowMaximumLatency(1000);

    /*
     * GENERATING THE NETWORK
     */
    Network net = new Network(25);
    net.addDevice(ccu);
    net.addDevice(ccu2);
    net.addDevice(tcu);
    net.addDevice(bcu);

    net.addSwitch(switch0);
    net.addSwitch(switch1);
    net.addSwitch(switch2);
    net.addSwitch(switch3);
    net.addSwitch(switch4);
    net.addSwitch(switch5);

    net.addFlow(flow1);
    net.addFlow(flow2);

    ScheduleGenerator scheduleGenerator = new ScheduleGenerator(false);
    scheduleGenerator.generateSchedule(net);

}

}