"""Definition of the Add/Subtract Component."""
import collections
import numpy as np
from scipy import sparse as sp
from six import string_types
from openmdao.core.explicitcomponent import ExplicitComponent
[docs]class AddSubtractComp(ExplicitComponent):
r"""
Compute a vectorized element-wise addition or subtraction.
Use the add_equation method to define any number of add/subtract relations
User defines the names of the input and output variables using
add_equation(output_name='my_output', input_names=['a','b', 'c', ...])
.. math::
result = a * \textrm{scaling factor}_a + b * \textrm{scaling factor}_b +
c * \textrm{scaling factor}_c + ...
where:
- all inputs shape (vec_size, n)
- b is of shape (vec_size, n)
- c is of shape (vec_size, n)
Result is of shape (vec_size, n)
All input vectors must be of the same shape, specified by the options 'vec_size' and 'length'.
Use scaling factor -1 for subtraction.
Attributes
----------
_add_systems : list
List of equation systems to be initialized with the system.
"""
[docs] def __init__(self, output_name=None, input_names=None, vec_size=1, length=1,
val=1.0, scaling_factors=None, **kwargs):
"""
Allow user to create an addition/subtracton system with one-liner.
Parameters
----------
output_name : str
(required) name of the result variable in this component's namespace.
input_names : iterable of str
(required) names of the input variables for this system
vec_size : int
Length of the first dimension of the input and output vectors
(i.e number of rows, or vector length for a 1D vector)
Default is 1
length : int
Length of the second dimension of the input and ouptut vectors (i.e. number of columns)
Default is 1 which results in input/output vectors of size (vec_size,)
scaling_factors : iterable of numeric
Scaling factors to apply to each input.
Use [1,1,...] for addition, [1,-1,...] for subtraction
Must be same length as input_names
Default is None which results in a scaling factor of 1 on
each input (element-wise addition)
val : float or list or tuple or ndarray
The initial value of the variable being added in user-defined units. Default is 1.0.
**kwargs : str
Any other arguments to pass to the addition system
(same as add_output method for ExplicitComponent)
Examples include units (str or None), desc (str)
"""
complexify = kwargs.pop('complex',False)
super(AddSubtractComp, self).__init__(complex=complexify)
self._add_systems = []
if isinstance(output_name, string_types):
self._add_systems.append((output_name, input_names, vec_size, length, val,
scaling_factors, kwargs))
elif isinstance(output_name, collections.Iterable):
raise NotImplementedError('Declaring multiple addition systems '
'on initiation is not implemented.'
'Use a string to name a single addition relationship or use '
'multiple add_output calls')
elif output_name is None:
pass
else:
raise ValueError(
"first argument to adder init must be either of type "
"`str' or 'None'")
[docs] def initialize(self):
"""
Declare options.
Parameters
----------
complex : Boolean
Set True to enable complex math (e.g. for complex step verification)
"""
self.options.declare('complex', default=False,
desc="Allocate as complex (e.g. for complex-step verification)")
[docs] def add_equation(self, output_name, input_names, vec_size=1, length=1, val=1.0,
units=None, res_units=None, desc='', lower=None, upper=None, ref=1.0,
ref0=0.0, res_ref=None, var_set=0, scaling_factors=None):
"""
Add an addition/subtraction relation.
Parameters
----------
output_name : str
(required) name of the result variable in this component's namespace.
input_names : iterable of str
(required) names of the input variables for this system
vec_size : int
Length of the first dimension of the input and output vectors
(i.e number of rows, or vector length for a 1D vector)
Default is 1
length : int
Length of the second dimension of the input and ouptut vectors (i.e. number of columns)
Default is 1 which results in input/output vectors of size (vec_size,)
scaling_factors : iterable of numeric
Scaling factors to apply to each input.
Use [1,1,...] for addition, [1,-1,...] for subtraction
Must be same length as input_names
Default is None which results in a scaling factor of 1 on
each input (element-wise addition)
val : float or list or tuple or ndarray
The initial value of the variable being added in user-defined units. Default is 1.0.
units : str or None
Units in which the output variables will be provided to the component during execution.
Default is None, which means it has no units.
res_units : str or None
Units in which the residuals of this output will be given to the user when requested.
Default is None, which means it has no units.
desc : str
description of the variable.
lower : float or list or tuple or ndarray or Iterable or None
lower bound(s) in user-defined units. It can be (1) a float, (2) an array_like
consistent with the shape arg (if given), or (3) an array_like matching the shape of
val, if val is array_like. A value of None means this output has no lower bound.
Default is None.
upper : float or list or tuple or ndarray or or Iterable None
upper bound(s) in user-defined units. It can be (1) a float, (2) an array_like
consistent with the shape arg (if given), or (3) an array_like matching the shape of
val, if val is array_like. A value of None means this output has no upper bound.
Default is None.
ref : float or ndarray
Scaling parameter. The value in the user-defined units of this output variable when
the scaled value is 1. Default is 1.
ref0 : float or ndarray
Scaling parameter. The value in the user-defined units of this output variable when
the scaled value is 0. Default is 0.
res_ref : float or ndarray
Scaling parameter. The value in the user-defined res_units of this output's residual
when the scaled value is 1. Default is 1.
var_set : hashable object
For advanced users only. ID or color for this variable, relevant for reconfigurability.
Default is 0.
"""
kwargs = {'units': units, 'res_units': res_units, 'desc': desc,
'lower': lower, 'upper': upper, 'ref': ref, 'ref0': ref0,
'res_ref': res_ref, 'var_set': var_set}
self._add_systems.append((output_name, input_names, vec_size, length, val,
scaling_factors, kwargs))
[docs] def add_output(self):
"""
Use add_equation instead of add_output to define equation systems.
"""
raise NotImplementedError('Use add_equation method, not add_output method'
'to create an addition/subtraction relation')
[docs] def setup(self):
"""
Set up the addition/subtraction system at run time.
"""
for (output_name, input_names, vec_size, length, val,
scaling_factors, kwargs) in self._add_systems:
if isinstance(input_names, string_types):
input_names = [input_names]
if scaling_factors is None:
scaling_factors = np.ones(len(input_names))
if len(scaling_factors) != len(input_names):
raise ValueError('Scaling factors list needs to be same length as input names')
if length == 1:
shape = (vec_size,)
else:
shape = (vec_size, length)
super(AddSubtractComp, self).add_output(output_name, val, shape=shape, **kwargs)
units = kwargs.pop('units', None)
desc = kwargs.pop('desc', '')
var_set = kwargs.pop('var_set', 0)
for i, input_name in enumerate(input_names):
self.add_input(input_name, shape=shape, units=units,
desc=desc + '_inp_' + input_name, var_set=var_set)
sf = scaling_factors[i]
self.declare_partials([output_name], [input_name],
val=sf * sp.eye(vec_size * length, format='csc'))
[docs] def compute(self, inputs, outputs):
"""
Compute the element wise addition or subtraction of inputs using numpy + operator.
Parameters
----------
inputs : Vector
unscaled, dimensional input variables read via inputs[key]
outputs : Vector
unscaled, dimensional output variables read via outputs[key]
"""
complexify = self.options['complex']
for (output_name, input_names, vec_size, length, val, scaling_factors,
kwargs) in self._add_systems:
if isinstance(input_names, string_types):
input_names = [input_names]
if scaling_factors is None:
scaling_factors = np.ones(len(input_names))
if length == 1:
shape = (vec_size,)
else:
shape = (vec_size, length)
if complexify:
temp = np.zeros(shape, dtype=np.complex_)
else:
temp = np.zeros(shape)
for i, input_name in enumerate(input_names):
sf = scaling_factors[i]
temp = temp + inputs[input_name] * sf
outputs[output_name] = temp