# Copyright 2018 The dm_control Authors.

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# http://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

# ============================================================================

"""Meta-variations that modify original values by a specified variation."""

from dm_control.composer.variation import base

from dm_control.composer.variation import variation_values

class Additive(base.Variation):

"""A variation that adds to an existing value.

This variation takes a value generated by another variation and adds it to an

existing value. In cumulative mode, the generated value is added to the

current value being varied. In non-cumulative mode, the generated value is

added to a fixed initial value.

"""

def __init__(self, variation, cumulative=False):

self._variation = variation

self._cumulative = cumulative

def __call__(self, initial_value=None, current_value=None, random_state=None):

base_value = current_value if self._cumulative else initial_value

return base_value + (

variation_values.evaluate(self._variation, initial_value, current_value,

random_state))

def __eq__(self, other):

if not isinstance(other, Additive):

return False

return (

self._variation == other._variation

and self._cumulative == other._cumulative

)

def __repr__(self):

return (

f"Additive(variation={self._variation}, cumulative={self._cumulative})"

)

class Multiplicative(base.Variation):

"""A variation that multiplies to an existing value.

This variation takes a value generated by another variation and multiplies it

to an existing value. In cumulative mode, the generated value is multiplied to

the current value being varied. In non-cumulative mode, the generated value is

multiplied to a fixed initial value.

"""

def __init__(self, variation, cumulative=False):

self._variation = variation

self._cumulative = cumulative

def __call__(self, initial_value=None, current_value=None, random_state=None):

base_value = current_value if self._cumulative else initial_value

return base_value * (

variation_values.evaluate(self._variation, initial_value, current_value,

random_state))

def __eq__(self, other):

if not isinstance(other, Multiplicative):

return False

return (

self._variation == other._variation

and self._cumulative == other._cumulative

)

def __repr__(self):

return (

f"Multiplicative(variation={self._variation}, "

f"cumulative={self._cumulative})"

)