def test_dimensions_of_expressions(self):
a = Quantity("a")
SI.set_quantity_dimension(a, length)
t = Quantity("t")
SI.set_quantity_dimension(t, time)
res = a**2 / t
# we can now determine the physical dimension of res
res_dim = SI.get_dimensional_expr(res)
self.assertTrue(dimsys_SI.equivalent_dims(res_dim, length**2 / time))
# In parameter dicts we can describe values along with units
a_val = Quantity("a_val")
SI.set_quantity_dimension(a_val, length)
SI.set_quantity_scale_factor(a_val, 5 * meter)
parameter_dict = {a: 5 * meter, t: 4 * second}
res_val = res.subs(parameter_dict)
# we can now determine the physical dimension of res_val
# and check it against the expected
print(SI.get_dimensional_expr(res_val))
self.assertTrue(
dimsys_SI.equivalent_dims(SI.get_dimensional_expr(res),
SI.get_dimensional_expr(res_val)))
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_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_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 v_unit(t):
# Note:
# At the moment t has to be a scalar
cond_1 = simplify(t) == 0
cond_2 = dimsys_SI.equivalent_dims(SI.get_dimensional_expr(t),
time)
assert cond_1 | cond_2
omega = 2 * pi / second
# phi = 0
phi = pi / 8
V_0 = 20 * meter / second
V_range = 5 * meter / second
return V_0 + V_range * sin(omega * t + phi)
def test_quantity_abs():
v_w1 = Quantity('v_w1')
v_w2 = Quantity('v_w2')
v_w3 = Quantity('v_w3')
v_w1.set_global_relative_scale_factor(1, meter / second)
v_w2.set_global_relative_scale_factor(1, meter / second)
v_w3.set_global_relative_scale_factor(1, meter / second)
expr = v_w3 - Abs(v_w1 - v_w2)
assert SI.get_dimensional_expr(v_w1) == (length / time).name
Dq = Dimension(SI.get_dimensional_expr(expr))
with warns_deprecated_sympy():
Dq1 = Dimension(Quantity.get_dimensional_expr(expr))
assert Dq == Dq1
assert SI.get_dimension_system().get_dimensional_dependencies(Dq) == {
'length': 1,
'time': -1,
}
assert meter == sqrt(meter**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_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,
}