####################################################################################################
#
# PySpice - A Spice Package for Python
# Copyright (C) 2017 Fabrice Salvaire
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
####################################################################################################
# Note: This module should be outsourced, only code specific to SPICE must remain.
"""This module implements units.
Shortcuts are defined to build unit values easily :
* for each unit prefix, e.g. :func:`pico`, :func:`nano`, :func:`micro`, :func:`milli`, :func:`kilo`,
:func:`mega`, :func:`tera`. These shortcuts return unit less values.
* for each unit and prefix as the concatenation of *u_*, the unit prefix and the
unit suffix, e.g. :func:`u_pV`, :func:`u_nV`, :func:`u_uV` :func:`u_mV`, :func:`u_V`,
:func:`u_kV`, :func:`u_MV`, :func:`u_TV`.
Theses unit value constructors accept int, float, object that can be converted to float,
:class:`UnitValue` instance and an iterable on these types.
A shortcut is defined to check an unit value match a particular unit, e.g. :func:`as_V`. Theses
shortcuts return the value if the unit match else it raises the exception *UnitError*.
A shortcut is defined to access each unit, e.g. :func:`U_V`, :func:`U_A`, :func:`U_s`, :func:`U_Hz`,
:func:`U_Ω`, :func:`U_F`, :func:`U_H.`, as well as for prefixes e.g. :func:`U_mV`.
Some shortcuts have Unicode and ASCII variants:
* For micro, we have the prefix *μ* and *u*.
* For Ohm, we have :func:`u_Ω` and :func:`u_Ohm`.
Some examples of usage:
.. code-block:: python3
foo = kilo(1) # unit less
resistance_unit = U_Ω
resistance1 = u_kΩ(1)
resistance1 = u_kOhm(1) # ASCII variant
resistance1 = 1@u_kΩ # using Python 3.5 syntax
resistance1 = 1 @u_kΩ # space doesn't matter
resistance1 = 1 @ u_kΩ #
resistance2 = as_Ω(resistance1) # check unit
resistances = u_kΩ(range(1, 11)) # same as [u_kΩ(x) for x in range(1, 11)]
resistances = range(1, 11)@u_kΩ # using Python 3.5 syntax
capacitance = u_uF(200)
inductance = u_mH(1)
temperature = u_Degree(25)
voltage = resistance1 * u_mA(1) # compute unit
frequency = u_ms(20).frequency
period = u_Hz(50).period
pulsation = frequency.pulsation
pulsation = period.pulsation
.. warning::
According to the Python `operator precedence
<https://docs.python.org/3/reference/expressions.html#operator-precedence>`_, division operators
have a higher priority than the matrix multiplication operator. In consequence you must had
parenthesis to perform something like :code:`(10@u_s) / (2@_us)`.
"""
####################################################################################################
import logging
import sys
from . import Unit as _Unit
from . import SiUnits as _SiUnits
####################################################################################################
_module_logger = logging.getLogger(__name__)
####################################################################################################
_version_info = sys.version_info
_has_matmul = _version_info.major * 10 + _version_info.minor >= 35
if not _has_matmul:
_module_logger.warning("Your Python version doesn't implement @ operator")
####################################################################################################
[docs]class UnitValueShorcut:
##############################################
def __init__(self, prefixed_unit):
self._prefixed_unit = prefixed_unit
##############################################
def _new_value(self, other):
return self._prefixed_unit.new_value(other)
##############################################
def __call__(self, other):
"""self(other)"""
return self._new_value(other)
##############################################
def __rmatmul__(self, other):
"""other @ self"""
return self._new_value(other)
####################################################################################################
def _to_ascii(name):
ascii_name = name
for args in (
('μ', 'u'),
('Ω', 'Ohm'),
('°C', 'Degree'),
):
ascii_name = ascii_name.replace(*args)
return ascii_name
[docs]def define_shortcut(name, shortcut) :
# ° is illegal in Python 3.5
# see https://docs.python.org/3/reference/lexical_analysis.html#identifiers
# https://www.python.org/dev/peps/pep-3131/
if '°' not in name:
globals()[name] = shortcut
ascii_name = _to_ascii(name)
if ascii_name != name:
globals()[ascii_name] = shortcut
####################################################################################################
# Define shortcuts for unit prefixes : ..., micro, milli, kilo, mega, ...
def _build_prefix_shortcut(unit_prefix):
unit_cls_name = unit_prefix.__class__.__name__
name = unit_cls_name.lower()
prefixed_unit = _Unit.PrefixedUnit(power=unit_prefix)
_Unit.PrefixedUnit.register(prefixed_unit)
shortcut = lambda value: _Unit.UnitValue(prefixed_unit, value)
define_shortcut(name, shortcut)
for unit_prefix in _Unit.UnitPrefixMetaclass.prefix_iter():
if unit_prefix.__class__ != _Unit.ZeroPower:
_build_prefix_shortcut(unit_prefix) # capture unit_prefix
####################################################################################################
# Fixme: better ???
[docs]class FrequencyValue(_Unit.UnitValue, _Unit.FrequencyMixin):
pass
# Fixme:
[docs]class FrequencyValues(_Unit.UnitValues): # , _Unit.FrequencyMixin
pass
[docs]class PeriodValue(_Unit.UnitValue, _Unit.PeriodMixin):
pass
[docs]class PeriodValues(_Unit.UnitValues): # , _Unit.PeriodMixin
pass
####################################################################################################
# Define unit shortcuts
def _build_unit_type_shortcut(unit):
name = 'U_' + unit.unit_suffix
define_shortcut(name, unit)
def _build_as_unit_shortcut(unit):
name = 'as_' + unit.unit_suffix
shortcut = unit.validate
define_shortcut(name, shortcut)
def _exec_body(ns, unit_prefix):
ns['__power__'] = unit_prefix
def _build_unit_prefix_shortcut(unit, unit_prefix):
name = 'u_' + str(unit_prefix) + unit.unit_suffix
if unit.__class__ == _SiUnits.Hertz:
value_ctor = FrequencyValue
values_ctor = FrequencyValues
elif unit.__class__ == _SiUnits.Second:
value_ctor = PeriodValue
values_ctor = PeriodValues
else:
value_ctor = _Unit.UnitValue
values_ctor = _Unit.UnitValues
prefixed_unit = _Unit.PrefixedUnit(unit, unit_prefix, value_ctor, values_ctor)
_Unit.PrefixedUnit.register(prefixed_unit)
define_shortcut('U' + name[1:], prefixed_unit)
shortcut = UnitValueShorcut(prefixed_unit)
define_shortcut(name, shortcut)
def _build_unit_shortcut(unit):
_build_as_unit_shortcut(unit)
_build_unit_type_shortcut(unit)
for unit_prefix in _Unit.UnitPrefixMetaclass.prefix_iter():
if unit_prefix.is_defined_in_spice:
_build_unit_prefix_shortcut(unit, unit_prefix)
for unit in _Unit.UnitMetaclass.unit_iter():
if unit.unit_suffix and unit.__class__ not in (_SiUnits.Kilogram,):
# Fixme: kilogram
_build_unit_shortcut(unit)
####################################################################################################
unit_value = _Unit.UnitValue.simple_value
Frequency = u_Hz
Period = u_s