"""

PDE1IVP - Base class for 1st-order partial differential equation initial-

value problems

This module provides the base functionality for all 1st-order partial

differential equation initial-value problem objects used in the nnode software.

Example:

Create an empty PDE1IVP object.

pde1ivp = PDE1IVP()

Create an PDE1IVP object from a Python module.

pde1ivp = PDE1IVP(modname)

The solution is assumed to be a function of m independent variables. In the

methods below, x is a vector of independent variables, and delY is the

Jacobian of the solution wrt the independent variables.

Attributes:

name - String containing name of equation definition module

G - Function for equation

bc[] - Vector of boundary condition functions for each variable;

only first element in each row is used since IVP

dG_dY - Function for derivative of Gf wrt Y

dG_ddelY - Array of function for derivative of Gf wrt dY/dx[j]

Ya - (Optional) function for analytical solution Ya(x)

delYa - (Optional) Array of functions for analytical Jacobian of solution

Methods:

Todo:

"""

from importlib import import_module

from pde1 import PDE1

class PDE1IVP(PDE1):

"""Base class for all 1st-order partial differential equation initial-

value problem objects"""

def __init__(self, diffeqmod=None):

"""

Constructor

Parameters:

diffeqmod - The name of the Python module containing the problem definition.

"""

super().__init__()

self.name = None

self.G = None

self.bc = None

self.dG_dY = None

self.dG_ddelY = None

self.Ya = None

self.delYa = None

if diffeqmod:

self.name = diffeqmod

pdemod = import_module(diffeqmod)

assert pdemod.G

assert pdemod.bc is not None

assert pdemod.dG_dY

assert pdemod.dG_ddelY

self.G = pdemod.G

self.bc = pdemod.bc

self.dG_dY = pdemod.dG_dY

self.dG_ddelY = pdemod.dG_ddelY

if pdemod.Ya:

self.Ya = pdemod.Ya

if pdemod.delYa:

self.delYa = pdemod.delYa

if __name__ == '__main__':

pde1ivp = PDE1IVP()

print(pde1ivp)