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GeezerVison is showing github.com — Complex matrices by lytex · Pull Request #376 · python-control/python-control

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@lytex

@lytex lytex commented Feb 29, 2020

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Now I've written new tests that use complex matrices without touching the old ones

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lytex added 5 commits February 9, 2020 21:52
@lytex
allow _ssmatrix to accept complex values
e6f2f60
@lytex
add new tests with complex state matrices
53dbfe4
@lytex
rename to test_evalfr_complex, use self.sysC332
05d730a
@lytex
missed one sys.evalfr in previous commit
a55165a
@lytex
missed one sys.evalfr in previous commit
2d231a8
bnavigator
bnavigator reviewed Mar 2, 2020
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Comment thread control/tests/statesp_test.py Outdated
def test_evalfr_complex(self):
"""Evaluate the frequency response at one frequency."""

resp = [[4.6799374736968655 -34.9854626345217383j,

@bnavigator bnavigator Mar 2, 2020

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Please be easier on the precision of your reference values. This will almost certainly fail on some build systems due to rounding errors or depending on the used BLAS/LAPACK implementation.

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@bnavigator

bnavigator commented Mar 2, 2020

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https://travis-ci.org/python-control/python-control/jobs/656662515#L1598-L1631

======================================================================
1599ERROR: test_multiply_ss_complex (control.tests.statesp_test.TestStateSpace)
1600Multiply two complex MIMO systems.
1601----------------------------------------------------------------------
1602Traceback (most recent call last):
1603  File "/home/travis/build/python-control/python-control/control/tests/statesp_test.py", line 690, in test_multiply_ss_complex
1604    np.testing.assert_array_almost_equal(sys.A, A)
1605  File "/home/travis/miniconda/envs/test-environment/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 1047, in assert_array_almost_equal
1606    precision=decimal)
1607  File "/home/travis/miniconda/envs/test-environment/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 834, in assert_array_compare
1608    max_rel_error = max(error[nonzero] / abs(y[nonzero]))
1609  File "/home/travis/miniconda/envs/test-environment/lib/python3.7/site-packages/numpy/matrixlib/defmatrix.py", line 195, in __getitem__
1610    out = N.ndarray.__getitem__(self, index)
1611IndexError: boolean index did not match indexed array along dimension 0; dimension is 1 but corresponding boolean dimension is 25
1612
1613======================================================================
1614FAIL: test_pole_complex (control.tests.statesp_test.TestStateSpace)
1615Evaluate the poles of a complex MIMO system.
1616----------------------------------------------------------------------
1617Traceback (most recent call last):
1618  File "/home/travis/build/python-control/python-control/control/tests/statesp_test.py", line 574, in test_pole_complex
1619    np.testing.assert_array_almost_equal(p, true_p)
1620  File "/home/travis/miniconda/envs/test-environment/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 1047, in assert_array_almost_equal
1621    precision=decimal)
1622  File "/home/travis/miniconda/envs/test-environment/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 765, in assert_array_compare
1623    raise AssertionError(msg)
1624AssertionError: 
1625Arrays are not almost equal to 6 decimals
1626
1627(shapes (3,), (2,) mismatch)
1628 x: array([-6.462073+2.870158j,  2.709877+6.291667j, 21.752196+7.838175j])
1629 y: array([ 2.709877 +6.291667j, 15.290123+10.708333j])
1630
1631----------------------------------------------------------------------
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@bnavigator

bnavigator commented Mar 2, 2020

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What happens if you call a function that uses slycot and give it a np.array(data, dtype=complex) (with imaginary part or without)? Will it fail gracefully, or will it give the wrong result without indication?
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@lytex

lytex commented Mar 3, 2020 •
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I've run statesp_test.py on my local machine, with slycot installed, I'm getting some complex casting warnings, but I don't know if there are more hidden cases failing without indication

slycot/transform.py:560: ComplexWarning: Casting complex values to real discards the imaginary part
  out = _wrapper.tb05ad_ng(n, m, p, jomega, A, B, C)
slycot/analysis.py:470: ComplexWarning: Casting complex values to real discards the imaginary part
  out = _wrapper.ab08nd(n,m,p,A,B,C,D,equil=equil,tol=tol,ldwork=ldwork)
slycot/transform.py:323: ComplexWarning: Casting complex values to real discards the imaginary part
  out = _wrapper.tb04ad_r(n,m,p,A,B,C,D,tol1,tol2,ldwork)

Regarding the second warning, there is a complex routine ab08nz in SLICOT we could use instead of ab08nd, so that should be pretty simple. No clue on the other ones, though.
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lytex added 2 commits March 3, 2020 05:09
@lytex
add complex to test_freq_resp
f1c9b9e
@lytex
remove warnings settings for debugging
e7a93ea
@lytex

lytex commented Mar 3, 2020 •
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I've made a more detailed traceback of the warnings:

======================================================================
ERROR: test_freq_resp_complex (__main__.TestStateSpace)
Evaluate the frequency response at multiple frequencies.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 732, in test_freq_resp_complex
    mag, phase, omega = self.sysC623.freqresp(true_omega)
  File "/home/julian/code/python/python-control/control/statesp.py", line 537, in freqresp
    self.B, self.C, job='NG')
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/slycot-0.3.5.21-py3.7-linux-x86_64.egg/slycot/transform.py", line 560, in tb05ad
    out = _wrapper.tb05ad_ng(n, m, p, jomega, A, B, C)
numpy.ComplexWarning: Casting complex values to real discards the imaginary part

======================================================================
ERROR: test_multiply_ss_complex (__main__.TestStateSpace)
Multiply two complex MIMO systems.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 692, in test_multiply_ss_complex
    np.testing.assert_array_almost_equal(sys.A, A)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 1047, in assert_array_almost_equal
    precision=decimal)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 834, in assert_array_compare
    max_rel_error = max(error[nonzero] / abs(y[nonzero]))
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/numpy/matrixlib/defmatrix.py", line 195, in __getitem__
    out = N.ndarray.__getitem__(self, index)
IndexError: boolean index did not match indexed array along dimension 0; dimension is 1 but corresponding boolean dimension is 25

======================================================================
ERROR: test_zero_mimo_sysC222_square_complex (__main__.TestStateSpace)
Evaluate the zeros of a square complex MIMO system.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 609, in test_zero_mimo_sysC222_square_complex
    z = np.sort(self.sysC222.zero())
  File "/home/julian/code/python/python-control/control/statesp.py", line 584, in zero
    self.A, self.B, self.C, self.D)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/slycot-0.3.5.21-py3.7-linux-x86_64.egg/slycot/analysis.py", line 470, in ab08nd
    out = _wrapper.ab08nd(n,m,p,A,B,C,D,equil=equil,tol=tol,ldwork=ldwork)
numpy.ComplexWarning: Casting complex values to real discards the imaginary part

======================================================================
ERROR: test_zero_mimo_sysC322_square_complex (__main__.TestStateSpace)
Evaluate the zeros of a square complex MIMO system.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 599, in test_zero_mimo_sysC322_square_complex
    z = np.sort(self.sysC322.zero())
  File "/home/julian/code/python/python-control/control/statesp.py", line 584, in zero
    self.A, self.B, self.C, self.D)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/slycot-0.3.5.21-py3.7-linux-x86_64.egg/slycot/analysis.py", line 470, in ab08nd
    out = _wrapper.ab08nd(n,m,p,A,B,C,D,equil=equil,tol=tol,ldwork=ldwork)
numpy.ComplexWarning: Casting complex values to real discards the imaginary part

======================================================================
ERROR: test_zero_mimo_sysC623_non_square_complex (__main__.TestStateSpace)
Evaluate the zeros of a non square complex MIMO system.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 618, in test_zero_mimo_sysC623_non_square_complex
    z = np.sort(self.sysC623.zero())
  File "/home/julian/code/python/python-control/control/statesp.py", line 584, in zero
    self.A, self.B, self.C, self.D)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/slycot-0.3.5.21-py3.7-linux-x86_64.egg/slycot/analysis.py", line 470, in ab08nd
    out = _wrapper.ab08nd(n,m,p,A,B,C,D,equil=equil,tol=tol,ldwork=ldwork)
numpy.ComplexWarning: Casting complex values to real discards the imaginary part

======================================================================
ERROR: test_zero_siso_complex (__main__.TestStateSpace)
Evaluate the zeros of a complex SISO system.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 584, in test_zero_siso_complex
    tfC111 = ss2tf(self.sysC222)
  File "/home/julian/code/python/python-control/control/xferfcn.py", line 1422, in ss2tf
    return _convert_to_transfer_function(sys)
  File "/home/julian/code/python/python-control/control/xferfcn.py", line 1184, in _convert_to_transfer_function
    array(sys.B), array(sys.C), array(sys.D), tol1=0.0)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/slycot-0.3.5.21-py3.7-linux-x86_64.egg/slycot/transform.py", line 323, in tb04ad
    out = _wrapper.tb04ad_r(n,m,p,A,B,C,D,tol1,tol2,ldwork)
numpy.ComplexWarning: Casting complex values to real discards the imaginary part

======================================================================
FAIL: test_pole_complex (__main__.TestStateSpace)
Evaluate the poles of a complex MIMO system.
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/julian/code/python/python-control/control/tests/statesp_test.py", line 576, in test_pole_complex
    np.testing.assert_array_almost_equal(p, true_p)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 1047, in assert_array_almost_equal
    precision=decimal)
  File "/home/julian/.virtualenvs/python-control/lib/python3.7/site-packages/numpy/testing/_private/utils.py", line 765, in assert_array_compare
    raise AssertionError(msg)
AssertionError: 
Arrays are not almost equal to 6 decimals

(shapes (3,), (2,) mismatch)
 x: array([-6.462073+2.870158j,  2.709877+6.291667j, 21.752196+7.838175j])
 y: array([ 2.709877 +6.291667j, 15.290123+10.708333j])

Tests failing with ComplexWarning

  • test_freq_resp_complex
  • test_zero_mimo_sysC222_square_complex
  • test_zero_mimo_sysC623_non_square_complex
  • test_zero_siso_complex

Test failing without ComplexWarning

  • test_multiply_ss_complex
  • test_pole_complex
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lytex added 4 commits March 3, 2020 05:24
@lytex
ease precision of reference values in test
bb44827
@lytex
Merge branch 'master' into complex
fc5c76b
@lytex
build an auxiliary system to compare against
5f58723 
If we compare sys.A against A we get a IndexError (not sure why), but
building a new auxiliary StateSpace seems to do the trick
@lytex
build an auxiliary system to compare against
1803d38 
If we compare sys.A against A we get a IndexError (not sure why), but
building a new auxiliary StateSpace seems to do the trick
@lytex

lytex commented Mar 31, 2020 •
edited
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Well, it seems that the current f2py interface doesn't support complex arrays as an argument. I've tried to use the complex routine ab08nz instead of ab08nd but I always get a SEGFAULT
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@bnavigator

bnavigator commented Mar 31, 2020

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So you wrote a wrapper for ab08nz? can you share that as PR in slycot and we see if the CI also segfaults?
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@bnavigator

bnavigator commented Mar 31, 2020

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According to the f2py typespec documentation, f2py signature files understand complex
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@lytex

lytex commented Apr 1, 2020

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Yes f2py does support complex, however I'm not sure if it supports a complex array

I'll do the pull request in a minute
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@lytex

lytex commented Apr 1, 2020

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This is the PR
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@lytex

lytex commented Apr 1, 2020

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So you wrote a wrapper for ab08nz? can you share that as PR in slycot and we see if the CI also segfaults?

Will the CI check a new function that it is just added or there is some config file to declare with functions will be teseted?
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@murrayrm

murrayrm commented Apr 1, 2020

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You need to write unit tests associated with any new functions that you add, otherwise they won't be checked. If you are adding something to slycot, the unit tests should go there, although I think the Travis CI builds for slycot also try running python-control unit tests, since python-control is the primary user of slycot (as far as I know).
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@lytex lytex mentioned this pull request Apr 1, 2020
Complex state matrices #371
Open
@lytex
add code to use slycot complex function ab08nz if any matrix is complex
84bc8ef
@lytex

lytex commented Apr 1, 2020

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I've changed control/statesp.py to use the complex-case function ab08nz in the complex branch.

The tests affected by this change should be test_zero_mimi_sysCXXX_square_complex, also new tests written in the complex branch
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@bnavigator

bnavigator commented Apr 1, 2020

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The PR here in python-control will only be able to access the new function in Slycot when your PR over there is merged, a new version is released and the CI in python-control/master is updated to use this new release. So please first amend python-control/Slycot#96 with a unit test, convince the maintainers to merge and wait for a release. The python-control unit tests which are run within Slycot's CI are also from master.

Of course you could also modify the CI scripts here and over at Slycot#96 to use your respective modified branches for development, but that won't be suitable for merging.

Thus I recommend to develop first in Slycot and as soon as that is done continue in python-control.
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@bnavigator bnavigator mentioned this pull request Apr 1, 2020
add ab08nz function to support complex state-space systems python-control/Slycot#96
Merged
@lytex

lytex commented Apr 3, 2020

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I've run statesp_test.py on my local machine, with slycot installed, I'm getting some complex casting warnings, but I don't know if there are more hidden cases failing without indication

slycot/transform.py:560: ComplexWarning: Casting complex values to real discards the imaginary part
  out = _wrapper.tb05ad_ng(n, m, p, jomega, A, B, C)
slycot/analysis.py:470: ComplexWarning: Casting complex values to real discards the imaginary part
  out = _wrapper.ab08nd(n,m,p,A,B,C,D,equil=equil,tol=tol,ldwork=ldwork)
slycot/transform.py:323: ComplexWarning: Casting complex values to real discards the imaginary part
  out = _wrapper.tb04ad_r(n,m,p,A,B,C,D,tol1,tol2,ldwork)

Regarding the second warning, there is a complex routine ab08nz in SLICOT we could use instead of ab08nd, so that should be pretty simple. No clue on the other ones, though.

ab08nd has been successfully changed to ab08nz thanks to @bnavigator
lytex/Slycot#1 and now the test_zero_mimo_sysCXXX_(non_)square_complex test pass.

tb05ad_ng and tb04ad_r are casting complex values to real, but as far as I know it seems there are no complex routine equivalents to these functions
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@bnavigator bnavigator mentioned this pull request Apr 5, 2020
Time to release a new version? python-control/Slycot#98
Closed
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bnavigator reviewed Jul 15, 2020
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So with the new Slycot out, I do not see a reason why python-control should not allow complex arrays. Through the "ComplexWarning", the user is informed that a function discarded the imaginary part and is thus not suitable for complex input (yet).

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Comment thread control/statesp.py
Comment on lines -96 to +104
arr = np.matrix(data, dtype=float)
if np.isrealobj(data):
arr = np.matrix(data, dtype=float)
elif np.iscomplexobj(data):
arr = np.matrix(data, dtype=complex)
else:
arr = np.array(data, dtype=float)
if np.isrealobj(data):
arr = np.array(data, dtype=float)
elif np.iscomplexobj(data):
arr = np.array(data, dtype=complex)

@bnavigator bnavigator Jul 15, 2020

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Is this really necessary? Why not just use matrix() and asarray() without dtype and figure out the dtype later?

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@bnavigator bnavigator Jul 29, 2020 •
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Turns out if dtype is omitted completely, it could still be int and trip operations later on.

The test suite already has complex casting warnings from Scipy and Slycot functions returning complex arrays (with 0 imaginary part), which are passed to _ssmatrix. Thus, my approach in #438 is to use dtype=np.result_type(np.float, arr), which ensures to cast from int to at least float and retains complex if arr is already complex.

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bnavigator added a commit to bnavigator/python-control that referenced this pull request Jul 29, 2020
@bnavigator
remove dtype from _ssmatrix conversion.
b65b719 
It is not necessary to enforce float and can raise
ComplexWarning during casting; cf. python-control#376
bnavigator added a commit to bnavigator/python-control that referenced this pull request Jul 29, 2020
@bnavigator
Change _ssmatrix conversion: allow complex dtype, (cf. python-control…
da7d6c0 
…#376)
@bnavigator bnavigator mentioned this pull request Jul 31, 2020
Refactor the test suite using pytest for array and matrix types #438
Merged
@bnavigator bnavigator added this to the 0.9.0 milestone Aug 17, 2020
@bnavigator bnavigator linked an issue Aug 17, 2020 that may be closed by this pull request
Complex state matrices #371
Open
bnavigator added a commit to bnavigator/python-control that referenced this pull request Aug 20, 2020
@bnavigator
Change _ssmatrix conversion: allow complex dtype, (cf. python-control…
c27dc73 
…#376)
@bnavigator bnavigator mentioned this pull request Nov 12, 2020
fixed StateSpace for complex inputs #468
Closed
bnavigator added a commit to bnavigator/python-control that referenced this pull request Dec 29, 2020
@bnavigator
Change _ssmatrix conversion: allow complex dtype, (cf. python-control…
5cbd205 
…#376)
bnavigator added a commit to bnavigator/python-control that referenced this pull request Dec 29, 2020
@bnavigator
Change _ssmatrix conversion: allow complex dtype, (cf. python-control…
a644f59 
…#376)
bnavigator added a commit to bnavigator/python-control that referenced this pull request Dec 29, 2020
@bnavigator
Change _ssmatrix conversion: allow complex dtype, (cf. python-control…
cad6332 
…#376)
This was referenced Dec 29, 2020
allow complex statespace matrices #484
Closed
Release 0.8.4 and 0.9.0 sequencing #451
Closed
@bnavigator bnavigator added the needs rebase The PR needs a rebase to current master branch label Jan 4, 2021
@murrayrm murrayrm removed this from the 0.9.0 milestone Jan 13, 2021
@lytex lytex closed this Jul 4, 2022
@murrayrm murrayrm mentioned this pull request Aug 14, 2026
Preserve complex StateSpace matrices #1230
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@lytex @bnavigator @murrayrm
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