Skip to content

Handle t_eval for static systems in input_output_response #743

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jun 7, 2022
Merged

Handle t_eval for static systems in input_output_response #743

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
13 changes: 1 addition & 12 deletions control/iosys.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1762,19 +1762,8 @@ def input_output_response(
warn("initial state too short; padding with zeros")
X0 = np.hstack([X0, np.zeros(sys.nstates - X0.size)])

# Check to make sure this is not a static function
# Compute the number of states
nstates = _find_size(sys.nstates, X0)
if nstates == 0:
# No states => map input to output
u = U[0] if len(U.shape) == 1 else U[:, 0]
y = np.zeros((np.shape(sys._out(T[0], X0, u))[0], len(T)))
for i in range(len(T)):
u = U[i] if len(U.shape) == 1 else U[:, i]
y[:, i] = sys._out(T[i], [], u)
return TimeResponseData(
T, y, None, U, issiso=sys.issiso(),
output_labels=sys.output_index, input_labels=sys.input_index,
transpose=transpose, return_x=return_x, squeeze=squeeze)

# create X0 if not given, test if X0 has correct shape
X0 = _check_convert_array(X0, [(nstates,), (nstates, 1)],
Expand Down
31 changes: 22 additions & 9 deletions control/tests/iosys_test.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1763,27 +1763,40 @@ def test_input_output_broadcasting():
resp_bad = ct.input_output_response(
sys, T, (U[0, :], U[:2, :-1]), [X0, P0])


def test_nonuniform_timepts():
@pytest.mark.parametrize("nstates, ninputs, noutputs", [
[2, 1, 1],
[4, 2, 3],
[0, 1, 1], # static function
[0, 3, 2], # static function
])
def test_nonuniform_timepts(nstates, noutputs, ninputs):
"""Test non-uniform time points for simulations"""
sys = ct.LinearIOSystem(ct.rss(2, 1, 1))
if nstates:
sys = ct.rss(nstates, noutputs, ninputs)
else:
sys = ct.ss(
[], np.zeros((0, ninputs)), np.zeros((noutputs, 0)),
np.random.rand(noutputs, ninputs))

# Start with a uniform set of times
unifpts = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
uniform = [1, 2, 3, 2, 1, -1, -3, -5, -7, -3, 1]
t_unif, y_unif = ct.input_output_response(sys, unifpts, uniform)
uniform = np.outer(
np.ones(ninputs), [1, 2, 3, 2, 1, -1, -3, -5, -7, -3, 1])
t_unif, y_unif = ct.input_output_response(
sys, unifpts, uniform, squeeze=False)

# Create a non-uniform set of inputs
noufpts = [0, 2, 4, 8, 10]
nonunif = [1, 3, 1, -7, 1]
t_nouf, y_nouf = ct.input_output_response(sys, noufpts, nonunif)
nonunif = np.outer(np.ones(ninputs), [1, 3, 1, -7, 1])
t_nouf, y_nouf = ct.input_output_response(
sys, noufpts, nonunif, squeeze=False)

# Make sure the outputs agree at common times
np.testing.assert_almost_equal(y_unif[noufpts], y_nouf, decimal=6)
np.testing.assert_almost_equal(y_unif[:, noufpts], y_nouf, decimal=6)

# Resimulate using a new set of evaluation points
t_even, y_even = ct.input_output_response(
sys, noufpts, nonunif, t_eval=unifpts)
sys, noufpts, nonunif, t_eval=unifpts, squeeze=False)
np.testing.assert_almost_equal(y_unif, y_even, decimal=6)


Expand Down