def test_convert_gwp(units, metric, species_in, species_out, expected_value):
# Bare masses can be converted
qty = registry.Quantity(1.0, units.format(""))
expected = registry(f"{expected_value} {units}")
observed = convert_gwp(metric, qty, species_in, species_out)
assert observed.units == expected.units
np.testing.assert_almost_equal(observed.magnitude, expected.magnitude)
# '[mass] [speciesname] (/ [time])' can be converted; the input species is extracted
# from the *qty* argument
qty = "1.0 " + units.format(species_in)
expected = registry(f"{expected_value} {units}")
observed = convert_gwp(metric, qty, species_out)
assert observed.units == expected.units
np.testing.assert_almost_equal(observed.magnitude, expected.magnitude)
# Tuple of (vector magnitude, unit expression) can be converted where the
# the unit expression contains the input species name
arr = np.array([1.0, 2.5, 0.1])
qty = (arr, units.format(species_in))
expected = arr * expected_value
# Conversion works
result = convert_gwp(metric, qty, species_out)
# Magnitudes are as expected
assert_array_almost_equal(result.magnitude, expected)
def test_convert_gwp_carbon(context):
# CO2 can be converted to C
qty = (44.0 / 12, "tonne CO2")
result = convert_gwp(context, qty, "C")
assert result.units == registry("tonne")
assert_almost_equal(result.magnitude, 1.0)
# C can be converted to CO2
qty = (1, "tonne C")
expected = registry.Quantity(44.0 / 12, "tonne")
assert convert_gwp(context, qty, "CO2e") == expected
def test_convert_gwp_carbon():
# CO2 can be converted to C
qty = (44. / 12, 'tonne CO2')
result = convert_gwp('AR5GWP100', qty, 'C')
assert result.units == registry('tonne')
assert_almost_equal(result.magnitude, 1.0)
# C can be converted to CO2
qty = (1, 'tonne C')
expected = registry.Quantity(44. / 12, 'tonne')
assert convert_gwp('AR5GWP100', qty, 'CO2e') == expected
def convert_gwp(context, qty, to):
"""Helper for :meth:`convert_unit` to perform GWP conversions."""
# Remove a leading 'gwp_' to produce the metric name
metric = context.split('gwp_')[1] if context else context
# Extract the species from *qty* and *to*, allowing supported aliases
species_from, units_from = extract_species(qty[1])
species_to, units_to = extract_species(to)
try:
# Convert using a (magnitude, unit) tuple with only units, and explicit
# input and output units
result = iam_units.convert_gwp(metric, (qty[0], units_from),
species_from, species_to)
except (AttributeError, ValueError):
# Missing *metric*, or *species_to* contains invalid units. pyam
# promises UndefinedUnitError in these cases. Use a subclass (above) to
# add a usage hint.
raise UndefinedUnitError(species_to) from None
except pint.DimensionalityError:
# Provide an exception with the user's inputs
raise pint.DimensionalityError(qty[1], to) from None
# Other exceptions are not caught and will pass up through convert_unit()
if units_to:
# Also convert the units
result = result.to(units_to)
else:
# *to* was only a species name. Provide units based on input and the
# output species name.
to = iam_units.format_mass(result, species_to, spec=':~')
return result, to
def convert_gwp(context, qty, to):
"""Helper for :meth:`convert_unit` to perform GWP conversions."""
# Remove a leading 'gwp_' to produce the metric name
metric = context.split('gwp_')[1]
# Split *to* into a 1- or 3-tuple of str. This allows for *to* to be:
_to = iam_units.emissions.pattern.split(to, maxsplit=1)
if len(_to) == 1:
# Only a species name ('CO2e') without any unit
species_to = _to[0]
units_to = None
else:
# An expression with both units and species name ('kg CO2e / year');
# to[1] is the species
species_to = _to[1]
# Other elements are pre- and suffix, e.g. 'kg ' and ' / year'
units_to = _to[0] + _to[2]
# Convert GWP using the (magnitude, unit-and-species) tuple in *qty*
result = iam_units.convert_gwp(metric, qty, species_to)
if units_to:
# Also convert the units
result = result.to(units_to)
else:
# *to* was only a species name; provide units based on input and the
# output species name
to = iam_units.format_mass(result, species_to, spec=':~')
return result, to