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Performance improvements to _remove_useless_states routine in statesp.py #248

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Merged
merged 4 commits into from
Apr 7, 2019
Merged

Performance improvements to _remove_useless_states routine in statesp.py #248

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394fa27
Performance improvements to _remove_useless_states routine in statesp.py
Dec 12, 2018
c65d085
Minor update to comment string in _remove_useless_states.
Dec 24, 2018
de2fc39
Merge branch 'master' into statesp-performance-improvements
adm78 Jan 11, 2019
be53eb7
Replace np.concatenate with np.union1d in statesp._remove_useless_sta…
Mar 25, 2019
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23 changes: 9 additions & 14 deletions control/statesp.py
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Original file line number Diff line number Diff line change
Expand Up @@ -194,20 +194,15 @@ def _remove_useless_states(self):

"""

# Indices of useless states.
useless = []

# Search for useless states.
for i in range(self.states):
if (all(self.A[i, :] == zeros((1, self.states))) and
all(self.B[i, :] == zeros((1, self.inputs)))):
useless.append(i)
# To avoid duplicate indices in useless, jump to the next
# iteration.
continue
if (all(self.A[:, i] == zeros((self.states, 1))) and
all(self.C[:, i] == zeros((self.outputs, 1)))):
useless.append(i)
# Search for useless states and get the indices of these states
# as an array.
ax1_A = np.where(~self.A.any(axis=1))[0]
ax1_B = np.where(~self.B.any(axis=1))[0]
ax0_A = np.where(~self.A.any(axis=0))[1]
ax0_C = np.where(~self.C.any(axis=0))[1]
useless_1 = np.intersect1d(ax1_A, ax1_B, assume_unique=True)
useless_2 = np.intersect1d(ax0_A, ax0_C, assume_unique=True)
useless = np.union1d(useless_1, useless_2)

# Remove the useless states.
self.A = delete(self.A, useless, 0)
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