# exception.py - exception definitions for the control package

#

# Initial author: Richard M. Murray

# Creation date: 31 May 2010

"""Exception definitions for the control package."""

class ControlSlycot(ImportError):

"""Slycot import failed."""

pass

class ControlDimension(ValueError):

"""Raised when dimensions of system objects are not correct."""

pass

class ControlArgument(TypeError):

"""Raised when arguments to a function are not correct."""

pass

class ControlIndexError(IndexError):

"""Raised when arguments to an indexed object are not correct."""

pass

class ControlMIMONotImplemented(NotImplementedError):

"""Function is not currently implemented for MIMO systems."""

pass

class ControlNotImplemented(NotImplementedError):

"""Functionality is not yet implemented."""

pass

# Utility function to see if Slycot is installed

slycot_installed = None

def slycot_check():

"""Return True if Slycot is installed, otherwise False."""

global slycot_installed

if slycot_installed is None:

try:

import slycot # noqa: F401

slycot_installed = True

except:

slycot_installed = False

return slycot_installed

# Utility function to see if pandas is installed

pandas_installed = None

def pandas_check():

"""Return True if pandas is installed, otherwise False."""

global pandas_installed

if pandas_installed is None:

try:

import pandas # noqa: F401

pandas_installed = True

except:

pandas_installed = False

return pandas_installed

# Utility function to see if cvxopt is installed

cvxopt_installed = None

def cvxopt_check():

"""Return True if cvxopt is installed, otherwise False."""

global cvxopt_installed

if cvxopt_installed is None:

try:

import cvxopt # noqa: F401

cvxopt_installed = True

except:

cvxopt_installed = False

return cvxopt_installed