SWMM 5.2 App Python Code for the Interface

This code is a Python interface to the SWMM5 simulation engine. It provides functions to control and obtain information from the SWMM5 simulation engine using the SWMM5 API. The functions cover various aspects of the simulation, including opening and running the simulation, reporting the results, and accessing the properties of the simulation objects, such as nodes and links. The code also includes a function to decode the simulation date and time into a Python datetime object.

"""Python SWMM5 interface"""

import ctypes

import platform

import datetime

_plat= platform.system()

if _plat=='Linux':

    _lib = ctypes.CDLL("libswmm5.so")

elif _plat=='Windows':

    _lib = ctypes.WinDLL(".\swmm5.dll")

else:

    Exception('Platform '+ _plat +' unsupported')

def getVersion():

    return _lib.swmm_getVersion()

def run(f1, f2, f3 = ''):

    return _lib.swmm_run(ctypes.c_char_p(f1.encode()), 

                        ctypes.c_char_p(f2.encode()), 

                        ctypes.c_char_p(f3.encode()))

def open(f1, f2, f3 = ''):

    return _lib.swmm_open(ctypes.c_char_p(f1.encode()), 

                        ctypes.c_char_p(f2.encode()), 

                        ctypes.c_char_p(f3.encode()))

def start(saveFlag):

    return _lib.swmm_start(ctypes.c_int(saveFlag))

def step():

    elapsed_time = ctypes.c_double()

    _lib.swmm_step(ctypes.byref(elapsed_time))

    return elapsed_time.value

def stride(strideStep):

    elapsed_time = ctypes.c_double()

    _lib.swmm_stride(ctypes.c_int(strideStep), ctypes.byref(elapsed_time))

    return elapsed_time.value

def end():

    _lib.swmm_end()

def getMassBalErr():     

    runoff = ctypes.c_float()

    flow = ctypes.c_float()

    qual = ctypes.c_float()

    _lib.swmm_getMassBalErr(

        ctypes.byref(runoff), ctypes.byref(flow), ctypes.byref(qual))

    return runoff.value, flow.value, qual.value

def report():

    return _lib.swmm_report()

def close():

  _lib.swmm_close()

def getWarnings():

    return _lib.swmm_getWarnings()

def getError():

    errmsg = ctypes.create_string_buffer(240)

    _lib.swmm_getError(ctypes.byref(errmsg), ctypes.c_int(240))

    return errmsg.value.decode()

def getCount(objtype):

    return _lib.swmm_getCount(ctypes.c_int(objtype))

def getName(objtype, index, size):

    name = ctypes.create_string_buffer(size)

    _lib.swmm_getName(

        ctypes.c_int(objtype), ctypes.c_int(index), ctypes.byref(name), ctypes.c_int(size))

    return name.value.decode()

def getIndex(objtype, name):

    return _lib.swmm_getIndex(ctypes.c_int(objtype), ctypes.c_char_p(name.encode()))

def getValue(property, index):

    _lib.swmm_getValue.restype = ctypes.c_double   

    return _lib.swmm_getValue(ctypes.c_int(property), ctypes.c_int(index))

def getSavedValue(property, index, period):

    _lib.swmm_getSavedValue.restype = ctypes.c_double   

    return _lib.swmm_getSavedValue(

        ctypes.c_int(property), ctypes.c_int(index), ctypes.c_int(period))

def setValue(property, index, value):

    _lib.swmm_setValue(

        ctypes.c_int(property), ctypes.c_int(index), ctypes.c_double(value))

def writeLine(line):

    _lib.swmm_writeLine(ctypes.c_char_p(line.encode()))

def decodeDate(date):

    """  Decodes a SWMM DateTime value to a Python DateTime value. """

    """  Use Python's datetime.weekday()  method to get day of week """

    """  (where Monday = 0 and Sunday = 6) if needed. """

    year= ctypes.c_int()

    month= ctypes.c_int()

    day= ctypes.c_int()

    hour= ctypes.c_int()

    minute= ctypes.c_int()

    second= ctypes.c_int()

    dayofweek= ctypes.c_int()

    _lib.swmm_decodeDate(

        ctypes.c_double(date), ctypes.byref(year), ctypes.byref(month),

        ctypes.byref(day),  ctypes.byref(hour), ctypes.byref(minute),

        ctypes.byref(second), ctypes.byref(dayofweek))

    d = datetime.datetime(

        year.value, month.value, day.value, hour.value, minute.value, second.value)

    return d