def test_eval_partial_derivative_expr1():
tau, alpha = symbols("tau alpha")
# this is only some special expression
# tested: vector derivative
# tested: scalar derivative
# tested: tensor derivative
base_expr1 = A(i) * H(-i, j) + A(i) * A(-i) * A(j) + tau**alpha * A(j)
tensor_derivative = PartialDerivative(base_expr1,
H(k, m))._perform_derivative()
vector_derivative = PartialDerivative(base_expr1,
A(k))._perform_derivative()
scalar_derivative = PartialDerivative(base_expr1,
tau)._perform_derivative()
assert (
tensor_derivative -
A(L_0) * L.metric(-L_0, -L_1) * L.delta(L_1, -k) * L.delta(j, -m)) == 0
assert (vector_derivative -
(tau**alpha * L.delta(j, -k) + L.delta(L_0, -k) * A(-L_0) * A(j) +
A(L_0) * L.metric(-L_0, -L_1) * L.delta(L_1, -k) * A(j) +
A(L_0) * A(-L_0) * L.delta(j, -k) +
L.delta(L_0, -k) * H(-L_0, j))).expand() == 0
assert (
vector_derivative.contract_metric(L.metric).contract_delta(L.delta) -
(tau**alpha * L.delta(j, -k) + A(L_0) * A(-L_0) * L.delta(j, -k) +
H(-k, j) + 2 * A(j) * A(-k))).expand() == 0
assert scalar_derivative - alpha * 1 / tau * tau**alpha * A(j) == 0
def test_tensor_partial_deriv():
# Test flatten:
expr = PartialDerivative(PartialDerivative(A(i), A(j)), A(i))
assert expr.expr == A(L_0)
assert expr.variables == (A(j), A(L_0))
expr1 = PartialDerivative(A(i), A(j))
assert expr1.expr == A(i)
assert expr1.variables == (A(j), )
expr2 = A(i) * PartialDerivative(H(k, -i), A(j))
assert expr2.get_indices() == [L_0, k, -L_0, -j]
expr2b = A(i) * PartialDerivative(H(k, -i), A(-j))
assert expr2b.get_indices() == [L_0, k, -L_0, j]
expr3 = A(i) * PartialDerivative(B(k) * C(-i) + 3 * H(k, -i), A(j))
assert expr3.get_indices() == [L_0, k, -L_0, -j]
expr4 = (A(i) + B(i)) * PartialDerivative(C(j), D(j))
assert expr4.get_indices() == [i, L_0, -L_0]
expr4b = (A(i) + B(i)) * PartialDerivative(C(-j), D(-j))
assert expr4b.get_indices() == [i, -L_0, L_0]
expr5 = (A(i) + B(i)) * PartialDerivative(C(-i), D(j))
assert expr5.get_indices() == [L_0, -L_0, -j]
def test_eval_partial_derivative_mixed_scalar_tensor_expr2():
tau, alpha = symbols("tau alpha")
base_expr2 = A(i)*A(-i) + tau**2
vector_expression = PartialDerivative(base_expr2, A(k))._perform_derivative()
assert (vector_expression -
(L.delta(L_0, -k)*A(-L_0) + A(L_0)*L.metric(-L_0, -L_1)*L.delta(L_1, -k))).expand() == 0
scalar_expression = PartialDerivative(base_expr2, tau)._perform_derivative()
assert scalar_expression == 2*tau
def test_eval_partial_derivative_expr_by_symbol():
tau, alpha = symbols("tau alpha")
expr1 = PartialDerivative(tau**alpha, tau)
assert expr1._perform_derivative() == alpha * 1 / tau * tau**alpha
expr2 = PartialDerivative(2 * tau + 3 * tau**4, tau)
assert expr2._perform_derivative() == 2 + 12 * tau**3
expr3 = PartialDerivative(2 * tau + 3 * tau**4, alpha)
assert expr3._perform_derivative() == 0
def test_replace_arrays_partial_derivative():
x, y, z, t = symbols("x y z t")
expr = PartialDerivative(A(i), A(j))
assert expr.replace_with_arrays({A(i): [x, y]}, [i, j]) == Array([[1, 0], [0, 1]])
expr = PartialDerivative(A(i), A(-i))
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 0
expr = PartialDerivative(A(-i), A(i))
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 0
def test_eval_partial_derivative_single_1st_rank_tensors_by_tensor():
expr1 = PartialDerivative(A(i), A(j))
assert expr1._perform_derivative() - L.delta(i, -j) == 0
expr2 = PartialDerivative(A(i), A(-j))
assert expr2._perform_derivative() - L.metric(i, L_0) * L.delta(-L_0,
j) == 0
expr3 = PartialDerivative(A(-i), A(-j))
assert expr3._perform_derivative() - L.delta(-i, j) == 0
expr4 = PartialDerivative(A(-i), A(j))
assert expr4._perform_derivative() - L.metric(-i, -L_0) * L.delta(L_0,
-j) == 0
expr5 = PartialDerivative(A(i), B(j))
expr6 = PartialDerivative(A(i), C(j))
expr7 = PartialDerivative(A(i), D(j))
expr8 = PartialDerivative(A(i), H(j, k))
assert expr5._perform_derivative() == 0
assert expr6._perform_derivative() == 0
assert expr7._perform_derivative() == 0
assert expr8._perform_derivative() == 0
expr9 = PartialDerivative(A(i), A(i))
assert expr9._perform_derivative() - L.delta(L_0, -L_0) == 0
expr10 = PartialDerivative(A(-i), A(-i))
assert expr10._perform_derivative() - L.delta(-L_0, L_0) == 0
def test_eval_partial_derivative_single_tensors_by_scalar():
tau, mu = symbols("tau mu")
expr = PartialDerivative(tau**mu, tau)
assert expr._perform_derivative() == mu * tau**mu / tau
expr1a = PartialDerivative(A(i), tau)
assert expr1a._perform_derivative() == 0
expr1b = PartialDerivative(A(-i), tau)
assert expr1b._perform_derivative() == 0
expr2a = PartialDerivative(H(i, j), tau)
assert expr2a._perform_derivative() == 0
expr2b = PartialDerivative(H(i, -j), tau)
assert expr2b._perform_derivative() == 0
expr2c = PartialDerivative(H(-i, j), tau)
assert expr2c._perform_derivative() == 0
expr2d = PartialDerivative(H(-i, -j), tau)
assert expr2d._perform_derivative() == 0
def test_expand_partial_derivative_product_rule():
# check product rule
expr4a = PartialDerivative(A(i) * B(j), D(k))
assert expr4a._expand_partial_derivative() == \
PartialDerivative(A(i), D(k))*B(j)\
+ A(i)*PartialDerivative(B(j), D(k))
expr4b = PartialDerivative(A(i) * B(j) * C(k), D(m))
assert expr4b._expand_partial_derivative() ==\
PartialDerivative(A(i), D(m))*B(j)*C(k)\
+ A(i)*PartialDerivative(B(j), D(m))*C(k)\
+ A(i)*B(j)*PartialDerivative(C(k), D(m))
expr4c = PartialDerivative(A(i) * B(j), C(k), D(m))
assert expr4c._expand_partial_derivative() ==\
PartialDerivative(A(i), C(k), D(m))*B(j) \
+ PartialDerivative(A(i), C(k))*PartialDerivative(B(j), D(m))\
+ PartialDerivative(A(i), D(m))*PartialDerivative(B(j), C(k))\
+ A(i)*PartialDerivative(B(j), C(k), D(m))
def test_expand_partial_derivative_full_linearity():
nneg = randint(0, 1000)
pos = randint(1, 1000)
neg = -randint(1, 1000)
c1 = Rational(nneg, pos)
c2 = Rational(neg, pos)
c3 = Rational(nneg, neg)
# check full linearity
p = PartialDerivative(42, D(j))
assert p and not p._expand_partial_derivative()
expr3a = PartialDerivative(nneg * A(i) + pos * B(i), D(j))
assert expr3a._expand_partial_derivative() ==\
nneg*PartialDerivative(A(i), D(j))\
+ pos*PartialDerivative(B(i), D(j))
expr3b = PartialDerivative(nneg * A(i) + neg * B(i), D(j))
assert expr3b._expand_partial_derivative() ==\
nneg*PartialDerivative(A(i), D(j))\
+ neg*PartialDerivative(B(i), D(j))
expr3c = PartialDerivative(neg * A(i) + pos * B(i), D(j))
assert expr3c._expand_partial_derivative() ==\
neg*PartialDerivative(A(i), D(j))\
+ pos*PartialDerivative(B(i), D(j))
expr3d = PartialDerivative(c1 * A(i) + c2 * B(i), D(j))
assert expr3d._expand_partial_derivative() ==\
c1*PartialDerivative(A(i), D(j))\
+ c2*PartialDerivative(B(i), D(j))
expr3e = PartialDerivative(c2 * A(i) + c1 * B(i), D(j))
assert expr3e._expand_partial_derivative() ==\
c2*PartialDerivative(A(i), D(j))\
+ c1*PartialDerivative(B(i), D(j))
expr3f = PartialDerivative(c2 * A(i) + c3 * B(i), D(j))
assert expr3f._expand_partial_derivative() ==\
c2*PartialDerivative(A(i), D(j))\
+ c3*PartialDerivative(B(i), D(j))
expr3g = PartialDerivative(c3 * A(i) + c2 * B(i), D(j))
assert expr3g._expand_partial_derivative() ==\
c3*PartialDerivative(A(i), D(j))\
+ c2*PartialDerivative(B(i), D(j))
expr3h = PartialDerivative(c3 * A(i) + c1 * B(i), D(j))
assert expr3h._expand_partial_derivative() ==\
c3*PartialDerivative(A(i), D(j))\
+ c1*PartialDerivative(B(i), D(j))
expr3i = PartialDerivative(c1 * A(i) + c3 * B(i), D(j))
assert expr3i._expand_partial_derivative() ==\
c1*PartialDerivative(A(i), D(j))\
+ c3*PartialDerivative(B(i), D(j))
def test_expand_partial_derivative_full_linearity():
pos_random_int1 = sympify(randint(0, 1000))
pos_random_int2 = sympify(randint(0, 1000))
neg_random_int = sympify(randint(-1000, -1))
c1 = Rational(pos_random_int1, pos_random_int2)
c2 = Rational(neg_random_int, pos_random_int2)
c3 = Rational(pos_random_int1, neg_random_int)
# check full linearity
expr3a = PartialDerivative(pos_random_int1 * A(i) + pos_random_int2 * B(i),
D(j))
assert expr3a._expand_partial_derivative() ==\
pos_random_int1*PartialDerivative(A(i), D(j))\
+ pos_random_int2*PartialDerivative(B(i), D(j))
expr3b = PartialDerivative(pos_random_int1 * A(i) + neg_random_int * B(i),
D(j))
assert expr3b._expand_partial_derivative() ==\
pos_random_int1*PartialDerivative(A(i), D(j))\
+ neg_random_int*PartialDerivative(B(i), D(j))
expr3c = PartialDerivative(neg_random_int * A(i) + pos_random_int2 * B(i),
D(j))
assert expr3c._expand_partial_derivative() ==\
neg_random_int*PartialDerivative(A(i), D(j))\
+ pos_random_int2*PartialDerivative(B(i), D(j))
expr3d = PartialDerivative(c1 * A(i) + c2 * B(i), D(j))
assert expr3d._expand_partial_derivative() ==\
c1*PartialDerivative(A(i), D(j))\
+ c2*PartialDerivative(B(i), D(j))
expr3e = PartialDerivative(c2 * A(i) + c1 * B(i), D(j))
assert expr3e._expand_partial_derivative() ==\
c2*PartialDerivative(A(i), D(j))\
+ c1*PartialDerivative(B(i), D(j))
expr3f = PartialDerivative(c2 * A(i) + c3 * B(i), D(j))
assert expr3f._expand_partial_derivative() ==\
c2*PartialDerivative(A(i), D(j))\
+ c3*PartialDerivative(B(i), D(j))
expr3g = PartialDerivative(c3 * A(i) + c2 * B(i), D(j))
assert expr3g._expand_partial_derivative() ==\
c3*PartialDerivative(A(i), D(j))\
+ c2*PartialDerivative(B(i), D(j))
expr3h = PartialDerivative(c3 * A(i) + c1 * B(i), D(j))
assert expr3h._expand_partial_derivative() ==\
c3*PartialDerivative(A(i), D(j))\
+ c1*PartialDerivative(B(i), D(j))
expr3i = PartialDerivative(c1 * A(i) + c3 * B(i), D(j))
assert expr3i._expand_partial_derivative() ==\
c1*PartialDerivative(A(i), D(j))\
+ c3*PartialDerivative(B(i), D(j))
def test_invalid_partial_derivative_valence():
raises(ValueError, lambda: PartialDerivative(C(j), D(-j)))
raises(ValueError, lambda: PartialDerivative(C(-j), D(j)))
def test_expand_partial_derivative_sum_rule():
tau = symbols("tau")
# check sum rule for D(tensor, symbol)
expr1aa = PartialDerivative(A(i), tau)
assert expr1aa._expand_partial_derivative() == PartialDerivative(A(i), tau)
expr1ab = PartialDerivative(A(i) + B(i), tau)
assert (
expr1ab._expand_partial_derivative() == PartialDerivative(A(i), tau) +
PartialDerivative(B(i), tau))
expr1ac = PartialDerivative(A(i) + B(i) + C(i), tau)
assert (
expr1ac._expand_partial_derivative() == PartialDerivative(A(i), tau) +
PartialDerivative(B(i), tau) + PartialDerivative(C(i), tau))
# check sum rule for D(tensor, D(j))
expr1ba = PartialDerivative(A(i), D(j))
assert expr1ba._expand_partial_derivative() ==\
PartialDerivative(A(i), D(j))
expr1bb = PartialDerivative(A(i) + B(i), D(j))
assert (
expr1bb._expand_partial_derivative() == PartialDerivative(A(i), D(j)) +
PartialDerivative(B(i), D(j)))
expr1bc = PartialDerivative(A(i) + B(i) + C(i), D(j))
assert expr1bc._expand_partial_derivative() ==\
PartialDerivative(A(i), D(j))\
+ PartialDerivative(B(i), D(j))\
+ PartialDerivative(C(i), D(j))
# check sum rule for D(tensor, H(j, k))
expr1ca = PartialDerivative(A(i), H(j, k))
assert expr1ca._expand_partial_derivative() ==\
PartialDerivative(A(i), H(j, k))
expr1cb = PartialDerivative(A(i) + B(i), H(j, k))
assert (expr1cb._expand_partial_derivative() == PartialDerivative(
A(i), H(j, k)) + PartialDerivative(B(i), H(j, k)))
expr1cc = PartialDerivative(A(i) + B(i) + C(i), H(j, k))
assert (expr1cc._expand_partial_derivative() == PartialDerivative(
A(i), H(j, k)) + PartialDerivative(B(i), H(j, k)) +
PartialDerivative(C(i), H(j, k)))
# check sum rule for D(D(tensor, D(j)), H(k, m))
expr1da = PartialDerivative(A(i), (D(j), H(k, m)))
assert expr1da._expand_partial_derivative() ==\
PartialDerivative(A(i), (D(j), H(k, m)))
expr1db = PartialDerivative(A(i) + B(i), (D(j), H(k, m)))
assert expr1db._expand_partial_derivative() ==\
PartialDerivative(A(i), (D(j), H(k, m)))\
+ PartialDerivative(B(i), (D(j), H(k, m)))
expr1dc = PartialDerivative(A(i) + B(i) + C(i), (D(j), H(k, m)))
assert expr1dc._expand_partial_derivative() ==\
PartialDerivative(A(i), (D(j), H(k, m)))\
+ PartialDerivative(B(i), (D(j), H(k, m)))\
+ PartialDerivative(C(i), (D(j), H(k, m)))
def test_replace_arrays_partial_derivative():
x, y, z, t = symbols("x y z t")
# d(A^i)/d(A_j) = d(g^ik A_k)/d(A_j) = g^ik delta_jk
expr = PartialDerivative(A(i), A(-j))
assert expr.get_free_indices() == [i, j]
assert expr.get_indices() == [i, j]
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, [i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, [i, j]) == Array([[1, 0], [0, -1]])
assert expr.replace_with_arrays({A(-i): [x, y], L: diag(1, 1)}, [i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(-i): [x, y], L: diag(1, -1)}, [i, j]) == Array([[1, 0], [0, -1]])
expr = PartialDerivative(A(i), A(j))
assert expr.get_free_indices() == [i, -j]
assert expr.get_indices() == [i, -j]
assert expr.replace_with_arrays({A(i): [x, y]}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(-i): [x, y], L: diag(1, 1)}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(-i): [x, y], L: diag(1, -1)}, [i, -j]) == Array([[1, 0], [0, 1]])
expr = PartialDerivative(A(-i), A(-j))
expr.get_free_indices() == [-i, j]
expr.get_indices() == [-i, j]
assert expr.replace_with_arrays({A(-i): [x, y]}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(-i): [x, y], L: diag(1, 1)}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(-i): [x, y], L: diag(1, -1)}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, [-i, j]) == Array([[1, 0], [0, 1]])
expr = PartialDerivative(A(i), A(i))
assert expr.get_free_indices() == []
assert expr.get_indices() == [L_0, -L_0]
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 2
expr = PartialDerivative(A(-i), A(-i))
assert expr.get_free_indices() == []
assert expr.get_indices() == [-L_0, L_0]
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 2
def test_replace_arrays_partial_derivative():
x, y, z, t = symbols("x y z t")
expr = PartialDerivative(A(i), A(j))
assert expr.replace_with_arrays({A(i): [x, y]}, [i, j]) == Array([[1, 0],
[0, 1]])
expr = PartialDerivative(A(i), A(-i))
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 0
expr = PartialDerivative(A(-i), A(i))
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 0
def test_eval_partial_derivative_single_2nd_rank_tensors_by_tensor():
expr1 = PartialDerivative(H(i, j), H(m, m1))
assert expr1._perform_derivative() - L.delta(i, -m) * L.delta(j, -m1) == 0
expr2 = PartialDerivative(H(i, j), H(-m, m1))
assert expr2._perform_derivative() - L.metric(i, L_0) * L.delta(
-L_0, m) * L.delta(j, -m1) == 0
expr3 = PartialDerivative(H(i, j), H(m, -m1))
assert expr3._perform_derivative() - L.delta(i, -m) * L.metric(
j, L_0) * L.delta(-L_0, m1) == 0
expr4 = PartialDerivative(H(i, j), H(-m, -m1))
assert expr4._perform_derivative() - L.metric(i, L_0) * L.delta(
-L_0, m) * L.metric(j, L_1) * L.delta(-L_1, m1) == 0
def test_eval_partial_derivative_divergence_type():
expr1a = PartialDerivative(A(i), A(i))
expr1b = PartialDerivative(A(i), A(k))
expr1c = PartialDerivative(L.delta(-i, k) * A(i), A(k))
assert (expr1a._perform_derivative() -
(L.delta(-i, k) * expr1b._perform_derivative())).contract_delta(
L.delta) == 0
assert (expr1a._perform_derivative() -
expr1c._perform_derivative()).contract_delta(L.delta) == 0
expr2a = PartialDerivative(H(i, j), H(i, j))
expr2b = PartialDerivative(H(i, j), H(k, m))
expr2c = PartialDerivative(
L.delta(-i, k) * L.delta(-j, m) * H(i, j), H(k, m))
assert (expr2a._perform_derivative() -
(L.delta(-i, k) * L.delta(-j, m) *
expr2b._perform_derivative())).contract_delta(L.delta) == 0
assert (expr2a._perform_derivative() -
expr2c._perform_derivative()).contract_delta(L.delta) == 0
def test_expand_partial_derivative_constant_factor_rule():
nneg = randint(0, 1000)
pos = randint(1, 1000)
neg = -randint(1, 1000)
c1 = Rational(nneg, pos)
c2 = Rational(neg, pos)
c3 = Rational(nneg, neg)
expr2a = PartialDerivative(nneg * A(i), D(j))
assert expr2a._expand_partial_derivative() ==\
nneg*PartialDerivative(A(i), D(j))
expr2b = PartialDerivative(neg * A(i), D(j))
assert expr2b._expand_partial_derivative() ==\
neg*PartialDerivative(A(i), D(j))
expr2ca = PartialDerivative(c1 * A(i), D(j))
assert expr2ca._expand_partial_derivative() ==\
c1*PartialDerivative(A(i), D(j))
expr2cb = PartialDerivative(c2 * A(i), D(j))
assert expr2cb._expand_partial_derivative() ==\
c2*PartialDerivative(A(i), D(j))
expr2cc = PartialDerivative(c3 * A(i), D(j))
assert expr2cc._expand_partial_derivative() ==\
c3*PartialDerivative(A(i), D(j))
def test_replace_arrays_partial_derivative():
x, y, z, t = symbols("x y z t")
# d(A^i)/d(A_j) = d(g^ik A_k)/d(A_j) = g^ik delta_jk
expr = PartialDerivative(A(i), A(-j))
assert expr.get_free_indices() == [i, j]
assert expr.get_indices() == [i, j]
assert expr.replace_with_arrays({
A(i): [x, y],
L: diag(1, 1)
}, [i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(i): [x, y],
L: diag(1, -1)
}, [i, j]) == Array([[1, 0], [0, -1]])
assert expr.replace_with_arrays({
A(-i): [x, y],
L: diag(1, 1)
}, [i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(-i): [x, y],
L: diag(1, -1)
}, [i, j]) == Array([[1, 0], [0, -1]])
expr = PartialDerivative(A(i), A(j))
assert expr.get_free_indices() == [i, -j]
assert expr.get_indices() == [i, -j]
assert expr.replace_with_arrays({A(i): [x, y]}, [i, -j]) == Array([[1, 0],
[0, 1]])
assert expr.replace_with_arrays({
A(i): [x, y],
L: diag(1, 1)
}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(i): [x, y],
L: diag(1, -1)
}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(-i): [x, y],
L: diag(1, 1)
}, [i, -j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(-i): [x, y],
L: diag(1, -1)
}, [i, -j]) == Array([[1, 0], [0, 1]])
expr = PartialDerivative(A(-i), A(-j))
expr.get_free_indices() == [-i, j]
expr.get_indices() == [-i, j]
assert expr.replace_with_arrays({A(-i): [x, y]}, [-i, j]) == Array([[1, 0],
[0,
1]])
assert expr.replace_with_arrays({
A(-i): [x, y],
L: diag(1, 1)
}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(-i): [x, y],
L: diag(1, -1)
}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(i): [x, y],
L: diag(1, 1)
}, [-i, j]) == Array([[1, 0], [0, 1]])
assert expr.replace_with_arrays({
A(i): [x, y],
L: diag(1, -1)
}, [-i, j]) == Array([[1, 0], [0, 1]])
expr = PartialDerivative(A(i), A(i))
assert expr.get_free_indices() == []
assert expr.get_indices() == [L_0, -L_0]
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 2
expr = PartialDerivative(A(-i), A(-i))
assert expr.get_free_indices() == []
assert expr.get_indices() == [-L_0, L_0]
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, 1)}, []) == 2
assert expr.replace_with_arrays({A(i): [x, y], L: diag(1, -1)}, []) == 2
expr = PartialDerivative(H(i, j) + H(j, i), A(i))
assert expr.get_indices() == [L_0, j, -L_0]
assert expr.get_free_indices() == [j]
expr = PartialDerivative(H(i, j) + H(j, i), A(k)) * B(-i)
assert expr.get_indices() == [L_0, j, -k, -L_0]
assert expr.get_free_indices() == [j, -k]
expr = PartialDerivative(A(i) * (H(-i, j) + H(j, -i)), A(j))
assert expr.get_indices() == [L_0, -L_0, L_1, -L_1]
assert expr.get_free_indices() == []
expr = A(j) * A(-j) + expr
assert expr.get_indices() == [L_0, -L_0, L_1, -L_1]
assert expr.get_free_indices() == []
expr = A(i) * (B(j) * PartialDerivative(C(-j), D(i)) +
C(j) * PartialDerivative(D(-j), B(i)))
assert expr.get_indices() == [L_0, L_1, -L_1, -L_0]
assert expr.get_free_indices() == []
expr = A(i) * PartialDerivative(C(-j), D(i))
assert expr.get_indices() == [L_0, -j, -L_0]
assert expr.get_free_indices() == [-j]
def test_expand_partial_derivative_constant_factor_rule():
pos_random_int1 = sympify(randint(0, 1000))
pos_random_int2 = sympify(randint(0, 1000))
neg_random_int = sympify(randint(-1000, -1))
c1 = Rational(pos_random_int1, pos_random_int2)
c2 = Rational(neg_random_int, pos_random_int2)
c3 = Rational(pos_random_int1, neg_random_int)
expr2a = PartialDerivative(pos_random_int1 * A(i), D(j))
assert expr2a._expand_partial_derivative() ==\
pos_random_int1*PartialDerivative(A(i), D(j))
expr2b = PartialDerivative(neg_random_int * A(i), D(j))
assert expr2b._expand_partial_derivative() ==\
neg_random_int*PartialDerivative(A(i), D(j))
expr2ca = PartialDerivative(c1 * A(i), D(j))
assert expr2ca._expand_partial_derivative() ==\
c1*PartialDerivative(A(i), D(j))
expr2cb = PartialDerivative(c2 * A(i), D(j))
assert expr2cb._expand_partial_derivative() ==\
c2*PartialDerivative(A(i), D(j))
expr2cc = PartialDerivative(c3 * A(i), D(j))
assert expr2cc._expand_partial_derivative() ==\
c3*PartialDerivative(A(i), D(j))