def test_pow():
v1 = ad.create_vector('v', [2, 5])
v2 = v1 ** 2
assert(v2[0].getValue() == 4)
assert(v2[1].getValue() == 25)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[4, 0], [0, 10]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 5)
v1 = np.array([x, y])
v2 = v1 ** 2
assert(v2[0].getValue() == 4)
assert(v2[1].getValue() == 25)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[4, 0], [0, 10]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = np.array([x, y])
v2 = (v1 ** 2) ** 3
assert(v2[0].getValue() == 64)
assert(v2[1].getValue() == 729)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[6 * (2 ** 5), 0], [0, 6 * (3 ** 5)]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = np.array([x, y])
v2 = np.array([y, 2])
v3 = v1 ** v2
assert(v3[0].getValue() == 8)
assert(v3[1].getValue() == 9)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[12, np.log(2) * 8], [0, 6]])))
def test_sin():
v1 = ad.create_vector('v', [0, 100])
v2 = ad.sin(v1)
assert(v2[0].getValue() == 0)
assert(np.isclose(v2[1].getValue(), np.sin(100)))
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, np.cos(100)]])))
v1 = ad.Scalar('x', 4)
v2 = ad.Scalar('y', 10)
v3 = ad.sin(np.array([v1, v2])) / ad.sin(np.array([v1, v2]))
assert(np.isclose(v3[0].getValue(), 1))
assert(np.isclose(v3[1].getValue(), 1))
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.isclose(jacobian, np.array([[0, 0], [0, 0]])).all())
v1 = ad.Scalar('x', 4)
v2 = ad.Scalar('y', 10)
v3 = ad.sin(np.array([v1, v2])) ** 2
assert(np.isclose(v3[0].getValue(), np.sin(4) ** 2))
assert(np.isclose(v3[1].getValue(), np.sin(10) ** 2))
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.isclose(jacobian, np.array([[2 * np.sin(4) * np.cos(4), 0], [0, 2 * np.sin(10) * np.cos(10)]])).all())
v1 = ad.Scalar('x', 4)
v2 = ad.Scalar('y', 10)
v3 = ad.sin(np.array([v1 * v2, v1 + v2])) ** 2
assert(np.isclose(v3[0].getValue(), np.sin(40) ** 2))
assert(np.isclose(v3[1].getValue(), np.sin(14) ** 2))
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.isclose(jacobian, np.array([[2 * np.sin(40) * np.cos(40) * 10, 2 * np.sin(40) * np.cos(40) * 4],
[2 * np.sin(14) * np.cos(14), 2 * np.sin(14) * np.cos(14)]])).all())
def test_create_vector():
v = ad.create_vector('v', [1, 2])
assert(v[0].getValue() == 1)
assert(v[1].getValue() == 2)
derivs = ad.get_deriv(v)
assert(np.array_equal(np.array([deriv.get('v1', 0) for deriv in derivs]), np.array([1, 0])))
assert(np.array_equal(np.array([deriv.get('v2', 0) for deriv in derivs]), np.array([0, 1])))
jacobian = ad.get_jacobian(v, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
jacobian = ad.get_jacobian(v, ['v1', 'v2', 'hello'])
assert(np.array_equal(jacobian, np.array([[1, 0, 0], [0, 1, 0]])))
v = ad.create_vector('v', [1, 2], [3, 4])
assert(v[0].getValue() == 1)
assert(v[1].getValue() == 2)
derivs = ad.get_deriv(v)
assert(np.array_equal(np.array([deriv.get('v1', 0) for deriv in derivs]), np.array([3, 0])))
assert(np.array_equal(np.array([deriv.get('v2', 0) for deriv in derivs]), np.array([0, 4])))
jacobian = ad.get_jacobian(v, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[3, 0], [0, 4]])))
jacobian = ad.get_jacobian(v, ['v1', 'v2', 'hello'])
assert(np.array_equal(jacobian, np.array([[3, 0, 0], [0, 4, 0]])))
with pytest.raises(Exception):
v = ad.create_vector('v', [1, 2], [3, 4, 5])
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v = np.array([x, y])
assert(np.array_equal(ad.get_value(v), np.array([1, 2])))
jacobian = ad.get_jacobian(v, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[0, 0], [0, 0]])))
jacobian = ad.get_jacobian(v, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v = np.array([x, 2 * y])
assert(np.array_equal(ad.get_value(v), np.array([1, 4])))
jacobian = ad.get_jacobian(v, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 2]])))
jacobian = ad.get_jacobian(v, ['y', 'x'])
assert(np.array_equal(jacobian, np.array([[0, 1], [2, 0]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v = np.array([x + y, 2 * y])
assert(np.array_equal(ad.get_value(v), np.array([3, 4])))
jacobian = ad.get_jacobian(v, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, 1], [0, 2]])))
jacobian = ad.get_jacobian(v, ['y', 'x'])
assert(np.array_equal(jacobian, np.array([[1, 1], [2, 0]])))
def test_tan():
v1 = ad.create_vector('v', [0, 100])
v2 = ad.tan(v1)
assert(v2[0].getValue() == 0)
assert(np.isclose(v2[1].getValue(), np.tan(100)))
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.isclose(jacobian, np.array([[1, 0], [0, 1 / (np.cos(100) ** 2)]])).all())
def test_cos():
#Similar to sin.
v1 = ad.create_vector('v', [0, 100])
v2 = ad.cos(v1)
assert(v2[0].getValue() == 1)
assert(np.isclose(v2[1].getValue(), np.cos(100)))
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.isclose(jacobian, np.array([[0, 0], [0, -np.sin(100)]])).all())
def test_neg():
v1 = ad.create_vector('v', [1, 2])
v2 = -v1
assert(v2[0].getValue() == -1)
assert(v2[1].getValue() == -2)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[-1, 0], [0, -1]])))
v3 = -v2
assert(v3[0].getValue() == 1)
assert(v3[1].getValue() == 2)
jacobian = ad.get_jacobian(v3, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
v1 = ad.create_vector('v', [1, 2])
v2 = -1 * -v1
assert(v2[0].getValue() == 1)
assert(v2[1].getValue() == 2)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
def test_exp():
v1 = ad.create_vector('v', [2, 5])
v2 = ad.exp(v1)
assert(np.isclose(v2[0].getValue(), np.exp(2)))
assert(np.isclose(v2[1].getValue(), np.exp(5)))
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[np.exp(2), 0], [0, np.exp(5)]])))
v1 = ad.create_vector('v', [2, 5])
v2 = ad.exp(2 * v1)
assert(np.isclose(v2[0].getValue(), np.exp(4)))
assert(np.isclose(v2[1].getValue(), np.exp(10)))
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, 2 * np.array([[np.exp(4), 0], [0, np.exp(10)]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = ad.exp(np.array([x + y, x * y]))
assert(np.isclose(v1[0].getValue(), np.exp(5)))
assert(np.isclose(v1[1].getValue(), np.exp(6)))
jacobian = ad.get_jacobian(v1, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[np.exp(5), np.exp(5)], [3 * np.exp(6), 2 * np.exp(6)]])))
def test_sub():
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = np.array([y, x])
v3 = v1 - v2
assert(v3[0].getValue() == -1)
assert(v3[1].getValue() == 1)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, -1], [-1, 1]])))
v1 = ad.create_vector('v', [1, 2])
v2 = v1 - 10
assert(v2[0].getValue() == -9)
assert(v2[1].getValue() == -8)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = ad.create_vector('v', [1, 5])
v3 = v1 - v2
assert(v3[0].getValue() == 0)
assert(v3[1].getValue() == -3)
jacobian = ad.get_jacobian(v3, ['x', 'y', 'v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0, -1, 0], [0, 1, 0, -1]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = np.array([y, 10])
v3 = v1 - v2
assert(v3[0].getValue() == -1)
assert(v3[1].getValue() == -8)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, -1], [0, 1]])))
def test_mul():
v1 = ad.create_vector('v', [1, 2])
v2 = ad.create_vector('w', [3, 5])
v3 = v1 * v2
assert(v3[0].getValue() == 3)
assert(v3[1].getValue() == 10)
jacobian = ad.get_jacobian(v3, ['v1', 'v2', 'w1', 'w2'])
assert(np.array_equal(jacobian, np.array([[3, 0, 1, 0], [0, 5, 0, 2]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v = ad.Scalar('v', 3)
v1 = np.array([x, y])
v2 = np.array([v, 3 * v])
v3 = v1 * v2
assert(v3[0].getValue() == 3)
assert(v3[1].getValue() == 18)
jacobian = ad.get_jacobian(v3, ['x', 'y', 'v'])
assert(np.array_equal(jacobian, np.array([[3, 0, 1], [0, 9, 6]])))
v1 = ad.create_vector('v', [2, 3])
v3 = v1 * v1
assert(v3[0].getValue() == 4)
assert(v3[1].getValue() == 9)
jacobian = ad.get_jacobian(v3, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[4, 0], [0, 6]])))
v1 = ad.create_vector('v', [1, 2])
v2 = v1 * 10
assert(v2[0].getValue() == 10)
assert(v2[1].getValue() == 20)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[10, 0], [0, 10]])))
x = ad.Scalar('x', 5)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = np.array([x * y, (x + y)])
v3 = v1 * v2
assert(v3[0].getValue() == 50)
assert(v3[1].getValue() == 14)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[20, 25], [2, 9]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = np.array([y, 10])
v3 = v1 * v2
assert(v3[0].getValue() == 2)
assert(v3[1].getValue() == 20)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[2, 1], [0, 10]])))
def test_add():
v1 = ad.create_vector('v', [1, 2])
v2 = ad.create_vector('v', [1, 5])
v3 = v1 + v2
assert(v3[0].getValue() == 2)
assert(v3[1].getValue() == 7)
jacobian = ad.get_jacobian(v3, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[2, 0], [0, 2]])))
v1 = ad.create_vector('v', [1, 2])
v2 = v1 + 10
assert(v2[0].getValue() == 11)
assert(v2[1].getValue() == 12)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
v1 = ad.create_vector('v', [1, 2])
v2 = ad.Scalar('v2', 4)
v3 = ad.Scalar('v1', 7)
v4 = v1 + np.array([v2, v3])
assert(v4[0].getValue() == 5)
assert(v4[1].getValue() == 9)
jacobian = ad.get_jacobian(v4, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[1, 1], [1, 1]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = ad.create_vector('v', [1, 5])
v3 = v1 + v2
assert(v3[0].getValue() == 2)
assert(v3[1].getValue() == 7)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, 0], [0, 1]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = np.array([x + y, x])
v3 = v1 + v2
assert(v3[0].getValue() == 4)
assert(v3[1].getValue() == 3)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[2, 1], [1, 1]])))
x = ad.Scalar('x', 1)
y = ad.Scalar('y', 2)
v1 = np.array([x, y])
v2 = np.array([y, 10])
v3 = v1 + v2
assert(v3[0].getValue() == 3)
assert(v3[1].getValue() == 12)
jacobian = ad.get_jacobian(v3, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[1, 1], [0, 1]])))
def test_rpow():
v1 = ad.create_vector('v', [2, 5])
v2 = 2 ** v1
assert(v2[0].getValue() == 4)
assert(v2[1].getValue() == 32)
jacobian = ad.get_jacobian(v2, ['v1', 'v2'])
assert(np.array_equal(jacobian, np.array([[np.log(2) * 4, 0], [0, np.log(2) * 32]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 5)
v1 = np.array([x, y])
v2 = 2 ** v1
assert(v2[0].getValue() == 4)
assert(v2[1].getValue() == 32)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[np.log(2) * 4, 0], [0, np.log(2) * 32]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = np.array([x, y])
v2 = 2 ** (2 * v1)
assert(v2[0].getValue() == 16)
assert(v2[1].getValue() == 64)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[np.log(2) * 32, 0], [0, np.log(2) * 128]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = np.array([x, y])
v2 = (2 ** 2) ** v1
assert(v2[0].getValue() == 16)
assert(v2[1].getValue() == 64)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[np.log(2) * (2 ** 4) * 2, 0], [0, np.log(2) * (2 ** 6) * 2]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = np.array([x + y, x])
v2 = (2 ** 2) ** v1
assert(v2[0].getValue() == 2 ** 10)
assert(v2[1].getValue() == 16)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[np.log(2) * (2 ** 10) * 2, np.log(2) * (2 ** 10) * 2], [np.log(2) * (2 ** 4) * 2, 0]])))
x = ad.Scalar('x', 2)
y = ad.Scalar('y', 3)
v1 = np.array([x + y, x])
v2 = 2 ** (2 * v1)
assert(v2[0].getValue() == 2 ** 10)
assert(v2[1].getValue() == 16)
jacobian = ad.get_jacobian(v2, ['x', 'y'])
assert(np.array_equal(jacobian, np.array([[np.log(2) * (2 ** 10) * 2, np.log(2) * (2 ** 10) * 2], [np.log(2) * (2 ** 4) * 2, 0]])))
def newtons_method(f, initial_guess, max_iter=1000, method='exact', tol=1e-12):
"""
Implements Newton's method for root-finding with different methods to find the step at each iteration
INPUTS
=======
f: Function
The function that we are trying to find a root of. The function must take in single list/array that has the same dimension as len(initial_guess).
initial_guess: List or array of ints/floats
The initial position to begin the search for the roots of the function 'f'.
max_iter: int
The max number of iterations
method: String
The method to solve Ax=b to find the step 'x' at each iteration.
Options:
'inverse' : calculate (A^-1)*b = x
'exact' : Use np.linalg.solve(A, b)
'gmres" : Use scipy.sparse.linalg.gmres(A, b), which finds a solution iteratively
'gmres_action' : Use np.linalg.gmres(L, b), where 'L' is a linear operator used to efficiently calculate A*x. Works well for functions with sparse Jacobian matrices.
tol: float
The tolerance. If the abs value of the steps for one iteration are less than the tol, then the algorithm stops
RETURNS
========
Tuple
A tuple with first entry which maps to the position of the minimum and second entry which maps to the number of iterations it took for the algorithm to stop.
NOTES
=====
POST:
- Returns a tuple. The first entry maps to the position of the minimum, and the second entry is the number of iterations it took for the algorithm to stop.
- If the convergence is not reached by 'max_iter', then a RuntimeError is thrown to alert the user.
"""
if method not in ['inverse', 'exact', 'gmres', 'gmres_action']:
raise Exception("Not a valid method.")
if len(f(initial_guess)) != len(initial_guess):
raise Exception(
'Output dimension of f should be the same as the input dimension of f.'
)
if method == 'gmres_action':
return _newtons_method_gmres_action(f, initial_guess, max_iter, tol)
x0 = ad.create_vector('x0', initial_guess)
for iter_num in range(max_iter):
fn = np.array(f(x0))
#need convert the list/array that is passed back from function, so downstream autodiff functions for vectors work properly
jacob = ad.get_jacobian(
fn, ['x0{}'.format(i) for i in range(1,
len(fn) + 1)])
if method == 'inverse':
step = np.linalg.inv(-jacob).dot(ad.get_value(fn))
if method == 'exact':
step = np.linalg.solve(-jacob, ad.get_value(fn))
elif method == 'gmres':
step, _ = gmres(jacob, -ad.get_value(fn), tol=tol, atol='legacy')
xnext = x0 + step
#check if we have converged
if np.all(np.abs(ad.get_value(xnext) - ad.get_value(x0)) < tol):
return (ad.get_value(xnext), iter_num + 1)
#update x0 because we have not converged yet
x0 = xnext
raise RuntimeError(
"Failed to converge after {0} iterations, value is {1}".format(
max_iter, ad.get_value(x0)))
