前端进度条性能优化、仿真结束后后处理优化；后端C代码生成流程优化：先识别来源，再按照已知未知量需求排序，最后局部求解

app/simulation/components/amesim/mechanical/pistons.py

@@ -8,6 +8,7 @@ from app.simulation.core.catalog import ComponentDisplaySpec, PortDisplaySpec
 from app.simulation.core.metadata import ParameterDefinition, ResultVariableDefinition
 from app.simulation.core.medium import GasMedium
 from app.simulation.core.ports import PortDefinition
+from app.simulation.core.port_computation import FLOW_SUPPLY
 AMESIM_REFERENCE_PRESSURE_PA = 101300.0
 
 class AmesimPnrp17(AlgebraicComponent):
@@ -19,7 +20,7 @@ class AmesimPnrp17(AlgebraicComponent):
     """
     MODEL_TYPE = 'amesim_pnrp17'
     MODEL_VERSION = '0.1.0'
-    PORTS = (PortDefinition.pneumatic('port_1', nominal_role='bidirectional'), PortDefinition.mechanical_translational('port_2'), PortDefinition.mechanical_translational('port_3'), PortDefinition.mechanical_translational('port_4'), PortDefinition.mechanical_translational('port_5'))
+    PORTS = (PortDefinition.pneumatic('port_1', computation=FLOW_SUPPLY), PortDefinition.mechanical_translational('port_2'), PortDefinition.mechanical_translational('port_3'), PortDefinition.mechanical_translational('port_4'), PortDefinition.mechanical_translational('port_5'))
     PARAMETERS = (AMESIM_GAS_INDEX_PARAMETER, ParameterDefinition('dp', 0.2, label='活塞直径', quantity='length', unit='m', minimum=0.0, minimum_exclusive=True, description='活塞外径；与活塞杆直径共同确定有效受压面积。'), ParameterDefinition('dr', 0.001, label='活塞杆直径', quantity='length', unit='m', minimum=0.0, description='穿过气室一侧的活塞杆直径，必须不大于活塞直径。'), ParameterDefinition('x0', 0.0, label='初始腔长', quantity='length', unit='m', description='机械端位移均为零时的气动腔长度。'))
     RESULT_VARIABLES = (ResultVariableDefinition('volume', '扫掠容积', 'volume', 'm3', 'derived', 10), ResultVariableDefinition('volume_flow', '扫掠容积变化率', 'volume_flow', 'm3/s', 'derived', 20), ResultVariableDefinition('length', '气动腔长度', 'length', 'm', 'derived', 30), ResultVariableDefinition('pressure_force', '气压力', 'force', 'N', 'derived', 40))
     DISPLAY = ComponentDisplaySpec(label='PNRP17 气动活塞', library_id='amesim', category_id='mechanical', symbol='amesim_pnrp17', ports=(PortDisplaySpec('port_1', 'left', order=10), PortDisplaySpec('port_3', 'left', order=20), PortDisplaySpec('port_2', 'left', order=30), PortDisplaySpec('port_4', 'right', order=40), PortDisplaySpec('port_5', 'right', order=50)), order=60)