def test_factor_and_dimension():
assert (3000, Dimension(1)) == Quantity._collect_factor_and_dimension(3000)
assert (1001, length) == Quantity._collect_factor_and_dimension(meter + km)
assert (2, length/time) == Quantity._collect_factor_and_dimension(
meter/second + 36*km/(10*hour))
x, y = symbols('x y')
assert (x + y/100, length) == Quantity._collect_factor_and_dimension(
x*m + y*centimeter)
cH = Quantity('cH', amount_of_substance/volume)
pH = -log(cH)
assert (1, volume/amount_of_substance) == Quantity._collect_factor_and_dimension(
exp(pH))
v_w1 = Quantity('v_w1', length/time, S(3)/2*meter/second)
v_w2 = Quantity('v_w2', length/time, 2*meter/second)
expr = Abs(v_w1/2 - v_w2)
assert (S(5)/4, length/time) == \
Quantity._collect_factor_and_dimension(expr)
expr = S(5)/2*second/meter*v_w1 - 3000
assert (-(2996 + S(1)/4), Dimension(1)) == \
Quantity._collect_factor_and_dimension(expr)
expr = v_w1**(v_w2/v_w1)
assert ((S(3)/2)**(S(4)/3), (length/time)**(S(4)/3)) == \
Quantity._collect_factor_and_dimension(expr)
def test_Quantity_eq():
u = Quantity("u", abbrev="dam")
v = Quantity("v1")
assert u != v
v = Quantity("v2", abbrev="ds")
assert u != v
v = Quantity("v3", abbrev="dm")
assert u != v
def test_print_unit_base():
with warnings.catch_warnings():
warnings.filterwarnings("ignore", category=SymPyDeprecationWarning)
A = Quantity("A", current, 1)
Js = Quantity("Js", action, 1)
mksa = UnitSystem((m, kg, s, A), (Js,))
assert mksa.print_unit_base(Js) == m**2*kg*s**-1/1000
def test_get_dimensional_expr_with_function():
v_w1 = Quantity('v_w1')
v_w2 = Quantity('v_w2')
v_w1.set_global_relative_scale_factor(1, meter / second)
v_w2.set_global_relative_scale_factor(1, meter / second)
assert SI.get_dimensional_expr(sin(v_w1)) == \
sin(SI.get_dimensional_expr(v_w1))
assert SI.get_dimensional_expr(sin(v_w1 / v_w2)) == 1
def test_convert_to():
A = Quantity("A")
A.set_global_relative_scale_factor(S.One, ampere)
Js = Quantity("Js")
Js.set_global_relative_scale_factor(S.One, joule * second)
mksa = UnitSystem((m, kg, s, A), (Js, ))
assert convert_to(Js, mksa._base_units) == m**2 * kg * s**-1 / 1000
def test_print_unit_base():
A = Quantity("A")
A.set_global_relative_scale_factor(S.One, ampere)
Js = Quantity("Js")
Js.set_global_relative_scale_factor(S.One, joule * second)
mksa = UnitSystem((m, kg, s, A), (Js, ))
with warns_deprecated_sympy():
assert mksa.print_unit_base(Js) == m**2 * kg * s**-1 / 1000
def test_Quantity_eq():
u = Quantity("u", length, 10, "dam")
v = Quantity("v1", length, 10)
assert u != v
v = Quantity("v2", time, 10, "ds")
assert u != v
v = Quantity("v3", length, 1, "dm")
assert u != v
def test_get_dimensional_expr_with_function():
v_w1 = Quantity('v_w1')
v_w2 = Quantity('v_w2')
v_w1.set_dimension(length/time)
v_w2.set_dimension(length/time)
v_w1.set_scale_factor(meter/second)
v_w2.set_scale_factor(meter/second)
assert Quantity.get_dimensional_expr(sin(v_w1)) == \
sin(Quantity.get_dimensional_expr(v_w1))
assert Quantity.get_dimensional_expr(sin(v_w1/v_w2)) == 1
def test_add_sub():
u = Quantity("u", length, 10)
v = Quantity("v", length, 5)
w = Quantity("w", time, 2)
assert isinstance(u + v, Add)
assert (u + v.convert_to(u)) == (1 + S.Half)*u
# TODO: eventually add this:
# assert (u + v).convert_to(u) == (1 + S.Half)*u
assert isinstance(u - v, Add)
assert (u - v.convert_to(u)) == S.Half*u
def test_issue_20288():
from sympy.core.numbers import E
from sympy.physics.units import energy
u = Quantity('u')
v = Quantity('v')
SI.set_quantity_dimension(u, energy)
SI.set_quantity_dimension(v, energy)
u.set_global_relative_scale_factor(1, joule)
v.set_global_relative_scale_factor(1, joule)
expr = 1 + exp(u**2 / v**2)
assert SI._collect_factor_and_dimension(expr) == (1 + E, Dimension(1))
def test_print_unit_base():
A = Quantity("A")
A.set_dimension(current)
A.set_scale_factor(S.One)
Js = Quantity("Js")
Js.set_dimension(action)
Js.set_scale_factor(S.One)
mksa = UnitSystem((m, kg, s, A), (Js, ))
with warns_deprecated_sympy():
assert mksa.print_unit_base(Js) == m**2 * kg * s**-1
def test_quantity_postprocessing():
q1 = Quantity('q1', length*pressure**2*temperature/time)
q2 = Quantity('q2', energy*pressure*temperature/(length**2*time))
assert q1 + q2
q = q1 + q2
Dq = Dimension(Quantity.get_dimensional_expr(q))
assert dimsys_default.get_dimensional_dependencies(Dq) == {
'length': -1,
'mass': 2,
'temperature': 1,
'time': -5,
}
def test_check_unit_consistency():
u = Quantity("u", length, 10)
v = Quantity("v", length, 5)
w = Quantity("w", time, 2)
def check_unit_consistency(expr):
Quantity._collect_factor_and_dimension(expr)
raises(ValueError, lambda: check_unit_consistency(u + w))
raises(ValueError, lambda: check_unit_consistency(u - w))
raises(ValueError, lambda: check_unit_consistency(u + 1))
raises(ValueError, lambda: check_unit_consistency(u - 1))
def test_quantity_abs():
v_w1 = Quantity('v_w1', length/time, meter/second)
v_w2 = Quantity('v_w2', length/time, meter/second)
v_w3 = Quantity('v_w3', length/time, meter/second)
expr = v_w3 - Abs(v_w1 - v_w2)
Dq = Dimension(Quantity.get_dimensional_expr(expr))
assert dimsys_default.get_dimensional_dependencies(Dq) == {
'length': 1,
'time': -1,
}
assert meter == sqrt(meter**2)
def test_abbrev():
u = Quantity("u", length, 1)
assert u.name == Symbol("u")
assert u.abbrev == Symbol("u")
u = Quantity("u", length, 2, "om")
assert u.name == Symbol("u")
assert u.abbrev == Symbol("om")
assert u.scale_factor == 2
assert isinstance(u.scale_factor, Number)
u = Quantity("u", length, 3*kilo, "ikm")
assert u.abbrev == Symbol("ikm")
assert u.scale_factor == 3000
def test_print_unit_base():
with warnings.catch_warnings():
warnings.filterwarnings("ignore", category=SymPyDeprecationWarning)
A = Quantity("A")
A.set_dimension(current)
A.set_scale_factor(S.One)
Js = Quantity("Js")
Js.set_dimension(action)
Js.set_scale_factor(S.One)
mksa = UnitSystem((m, kg, s, A), (Js,))
assert mksa.print_unit_base(Js) == m**2*kg*s**-1/1000
def test_issue_22164():
warnings.simplefilter("error")
dm = Quantity("dm")
SI.set_quantity_dimension(dm, length)
SI.set_quantity_scale_factor(dm, 1)
bad_exp = Quantity("bad_exp")
SI.set_quantity_dimension(bad_exp, length)
SI.set_quantity_scale_factor(bad_exp, 1)
expr = dm**bad_exp
# deprecation warning is not expected here
SI._collect_factor_and_dimension(expr)
def test_dimensional_expr_of_derivative():
l = Quantity('l', length, 36 * km)
t = Quantity('t', time, hour)
t1 = Quantity('t1', time, second)
x = Symbol('x')
y = Symbol('y')
f = Function('f')
dfdx = f(x, y).diff(x, y)
dl_dt = dfdx.subs({f(x, y): l, x: t, y: t1})
assert Quantity.get_dimensional_expr(dl_dt) ==\
Quantity.get_dimensional_expr(l / t / t1) ==\
Symbol("length")/Symbol("time")**2
assert Quantity._collect_factor_and_dimension(dl_dt) ==\
Quantity._collect_factor_and_dimension(l / t / t1) ==\
(10, length/time**2)
def test_add_sub():
u = Quantity("u")
v = Quantity("v")
w = Quantity("w")
u.set_global_relative_scale_factor(S(10), meter)
v.set_global_relative_scale_factor(S(5), meter)
w.set_global_relative_scale_factor(S(2), second)
assert isinstance(u + v, Add)
assert (u + v.convert_to(u)) == (1 + S.Half) * u
# TODO: eventually add this:
# assert (u + v).convert_to(u) == (1 + S.Half)*u
assert isinstance(u - v, Add)
assert (u - v.convert_to(u)) == S.Half * u
def test_quantity_postprocessing():
q1 = Quantity('q1')
q2 = Quantity('q2')
SI.set_quantity_dimension(q1, length*pressure**2*temperature/time)
SI.set_quantity_dimension(q2, energy*pressure*temperature/(length**2*time))
assert q1 + q2
q = q1 + q2
Dq = Dimension(SI.get_dimensional_expr(q))
assert SI.get_dimension_system().get_dimensional_dependencies(Dq) == {
'length': -1,
'mass': 2,
'temperature': 1,
'time': -5,
}
def test_deprecated_quantity_methods():
step = Quantity("step")
with warns_deprecated_sympy():
step.set_dimension(length)
step.set_scale_factor(2*meter)
assert convert_to(step, centimeter) == 200*centimeter
assert convert_to(1000*step/second, kilometer/second) == 2*kilometer/second
def test_factor_and_dimension_with_Abs():
with warns_deprecated_sympy():
v_w1 = Quantity('v_w1', length/time, S(3)/2*meter/second)
v_w1.set_dimension(length/time)
v_w1.set_scale_factor(S(3)/2*meter/second)
expr = v_w1 - Abs(v_w1)
assert (0, length/time) == Quantity._collect_factor_and_dimension(expr)
def prefix_unit(unit, prefixes):
"""
Return a list of all units formed by unit and the given prefixes.
You can use the predefined PREFIXES or BIN_PREFIXES, but you can also
pass as argument a subdict of them if you don't want all prefixed units.
>>> from sympy.physics.units.prefixes import (PREFIXES,
... prefix_unit)
>>> from sympy.physics.units.systems import MKS
>>> from sympy.physics.units import m
>>> pref = {"m": PREFIXES["m"], "c": PREFIXES["c"], "d": PREFIXES["d"]}
>>> prefix_unit(m, pref) #doctest: +SKIP
[cm, dm, mm]
"""
from sympy.physics.units.quantities import Quantity
prefixed_units = []
for prefix_abbr, prefix in prefixes.items():
quantity = Quantity("%s%s" % (prefix.name, unit.name),
abbrev=("%s%s" % (prefix.abbrev, unit.abbrev)))
quantity.set_dimension(unit.dimension)
quantity.set_scale_factor(unit.scale_factor * prefix)
prefixed_units.append(quantity)
return prefixed_units
def test_check_unit_consistency():
u = Quantity("u")
v = Quantity("v")
w = Quantity("w")
u.set_global_relative_scale_factor(S(10), meter)
v.set_global_relative_scale_factor(S(5), meter)
w.set_global_relative_scale_factor(S(2), second)
def check_unit_consistency(expr):
SI._collect_factor_and_dimension(expr)
raises(ValueError, lambda: check_unit_consistency(u + w))
raises(ValueError, lambda: check_unit_consistency(u - w))
raises(ValueError, lambda: check_unit_consistency(u + 1))
raises(ValueError, lambda: check_unit_consistency(u - 1))
raises(ValueError, lambda: check_unit_consistency(1 - exp(u / w)))
def test_factor_and_dimension_with_Abs():
with warns_deprecated_sympy():
v_w1 = Quantity('v_w1', length / time, Rational(3, 2) * meter / second)
v_w1.set_global_relative_scale_factor(Rational(3, 2), meter / second)
expr = v_w1 - Abs(v_w1)
with warns_deprecated_sympy():
assert (0,
length / time) == Quantity._collect_factor_and_dimension(expr)
def test_dimensional_expr_of_derivative():
l = Quantity("l")
t = Quantity("t")
t1 = Quantity("t1")
l.set_global_relative_scale_factor(36, km)
t.set_global_relative_scale_factor(1, hour)
t1.set_global_relative_scale_factor(1, second)
x = Symbol("x")
y = Symbol("y")
f = Function("f")
dfdx = f(x, y).diff(x, y)
dl_dt = dfdx.subs({f(x, y): l, x: t, y: t1})
assert (SI.get_dimensional_expr(dl_dt) == SI.get_dimensional_expr(
l / t / t1) == Symbol("length") / Symbol("time")**2)
assert (SI._collect_factor_and_dimension(dl_dt) ==
SI._collect_factor_and_dimension(l / t / t1) ==
(10, length / time**2))
def test_quantity_postprocessing():
q1 = Quantity("q1")
q2 = Quantity("q2")
SI.set_quantity_dimension(q1, length * pressure**2 * temperature / time)
SI.set_quantity_dimension(
q2, energy * pressure * temperature / (length**2 * time))
assert q1 + q2
q = q1 + q2
Dq = Dimension(SI.get_dimensional_expr(q))
assert SI.get_dimension_system().get_dimensional_dependencies(Dq) == {
"length": -1,
"mass": 2,
"temperature": 1,
"time": -5,
}
def test_extend():
ms = UnitSystem((m, s), (c,))
Js = Quantity("Js", action, 1)
mks = ms.extend((kg,), (Js,))
res = UnitSystem((m, s, kg), (c, Js))
assert set(mks._base_units) == set(res._base_units)
assert set(mks._units) == set(res._units)
def test_mul_div():
u = Quantity("u")
v = Quantity("v")
t = Quantity("t")
ut = Quantity("ut")
v2 = Quantity("v")
u.set_global_relative_scale_factor(S(10), meter)
v.set_global_relative_scale_factor(S(5), meter)
t.set_global_relative_scale_factor(S(2), second)
ut.set_global_relative_scale_factor(S(20), meter * second)
v2.set_global_relative_scale_factor(S(5), meter / second)
assert 1 / u == u**(-1)
assert u / 1 == u
v1 = u / t
v2 = v
# Pow only supports structural equality:
assert v1 != v2
assert v1 == v2.convert_to(v1)
# TODO: decide whether to allow such expression in the future
# (requires somehow manipulating the core).
# assert u / Quantity('l2', dimension=length, scale_factor=2) == 5
assert u * 1 == u
ut1 = u * t
ut2 = ut
# Mul only supports structural equality:
assert ut1 != ut2
assert ut1 == ut2.convert_to(ut1)
# Mul only supports structural equality:
lp1 = Quantity("lp1")
lp1.set_global_relative_scale_factor(S(2), 1 / meter)
assert u * lp1 != 20
assert u**0 == 1
assert u**1 == u
# TODO: Pow only support structural equality:
u2 = Quantity("u2")
u3 = Quantity("u3")
u2.set_global_relative_scale_factor(S(100), meter**2)
u3.set_global_relative_scale_factor(Rational(1, 10), 1 / meter)
assert u**2 != u2
assert u**-1 != u3
assert u**2 == u2.convert_to(u)
assert u**-1 == u3.convert_to(u)
def test_dimensional_expr_of_derivative():
l = Quantity('l')
t = Quantity('t')
t1 = Quantity('t1')
l.set_global_relative_scale_factor(36, km)
t.set_global_relative_scale_factor(1, hour)
t1.set_global_relative_scale_factor(1, second)
x = Symbol('x')
y = Symbol('y')
f = Function('f')
dfdx = f(x, y).diff(x, y)
dl_dt = dfdx.subs({f(x, y): l, x: t, y: t1})
assert SI.get_dimensional_expr(dl_dt) ==\
SI.get_dimensional_expr(l / t / t1) ==\
Symbol("length")/Symbol("time")**2
assert SI._collect_factor_and_dimension(dl_dt) ==\
SI._collect_factor_and_dimension(l / t / t1) ==\
(10, length/time**2)
