Matthias,

I'm glad oct2py has proven useful to you. Have you tried running similar code directly in octave? I will try it both ways and let you know what I get. Yes, the tracebacks should be clearer as to where the error source is. I'll take that as a bug of its own.

Regards,

Steve Silvester

On Sep 27, 2012, at 8:23 AM, MatthiasKauer [email protected] wrote:

Hi,
I'm trying to use octave's c2d function to transfer a continuous time control system to a discrete one.
This seems to work fine as long as A, B are the same size. The code below however (where B is 2x1) fails however informing me that the numbers of columns must match (in the temporary .mat file, I assume)

I'm using scipy 0.9.0, python 2.7 (both installed from the ubuntu repos) and oct2py-0.3.5-py2.7.egg that I installed via easy-install (and that was working fine for solving the discrete algebraic Riccati equation - helped me out big time!)

Code:
from oct2py import Oct2Py
oc = Oct2Py()
import scipy as sp

A = sp.array([[1.0, 1.0],[0,1.0]])
B = sp.array([ [1.0], [0.0] ])
C =sp.eye(2)

sys = oc.ss(A,B,C,[])
print sys
dsys = oc.call('c2d', sys,0.5)
print dsys

OUTPUT:
{'a': array([[ 1., 1.],
[ 0., 1.]]), 'c': array([[ 1., 0.],
[ 0., 1.]]), 'b': array([[ 1.],
[ 0.]]), 'd': array([[ 0.],
[ 0.]]), 'stname': [u'x1', u'x_2'], 'tsam': 0.0, 'n': 2.0, 'sys': array([[ 2., 0., 0., 1.]]), 'nz': 0.0, 'outname': [u'y_1', u'y_2'], 'yd': array([[ 0., 0.]]), 'inname': u'u_1'}
Traceback (most recent call last):
File "/media/sf_Dropbox/Work_2012_07+/ConVerIterate/Python/oct2py_experiment/oct2py_c2d.py", line 21, in
dsys = oc.call('c2d', sys,0.5)
File "/usr/local/lib/python2.7/dist-packages/oct2py-0.3.5-py2.7.egg/oct2py/_oct2py.py", line 211, in call
resp = self._eval(cmd, verbose=verbose)
File "/usr/local/lib/python2.7/dist-packages/oct2py-0.3.5-py2.7.egg/oct2py/_oct2py.py", line 360, in _eval
raise Oct2PyError(msg)
oct2py.utils.Oct2PyError: """
load /tmp/tmpuBWU8L.mat "A" "B"
[a] = c2d(A, B)
save "-v6" /tmp/tmpHwjPoP.mat "a"
"""
number of columns must match (5 != 3)

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Matthias,

I fixed the bug in the latest repository. Cheers.

from oct2py.

Hi Steve,
I'm impressed that you could fix this so quickly.

Just to confirm: I can not get this fix via easy-install yet, can I? git clone -> setup.py or something similar is required, right?

from oct2py.

Correct, but I'll try to release 0.3.6 this weekend.

Regards,

Steve Silvester

On Oct 5, 2012, at 11:22 PM, MatthiasKauer [email protected] wrote:

Hi Steve,
I'm impressed that you could fix this so quickly.

Just to confirm: I can not get this fix via easy-install yet, can I? git clone -> setup.py or something similar is required, right?

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Sorry for the confusion if you had tried to use the git master repo, I had made the change in the 0.3.4 branch instead of the main. All changes have been merged to main, and I released 0.3.6, which should address your issue.

Cheers.

from oct2py.

hi, I just tried running easy_install oct2py and it told me that
"oct2py 0.3.5 is already the active version in easy-install.pth"

Am I doing something wrong? [Ubuntu 12.04, Python 2.7]

from oct2py.

Does this work?
easy_install --upgrade oct2py

Regards,

Steve Silvester

On Oct 15, 2012, at 6:59 PM, MatthiasKauer [email protected] wrote:

hi, I just tried running easy_install oct2py and it told me that
"oct2py 0.3.5 is already the active version in easy-install.pth"

Am I doing something wrong?

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I think the install worked now.
Bug is still the same however. Did you only change the error messages?

Should I start examining the temporary .mat files?

Traceback (most recent call last):
File "/media/sf_Forge/Work_2012_07+/ConVerIterate/Python/oct2py_experiment/oct2py_c2d.py", line 21, in
dsys = oc.call('c2d', sys,0.5)
File "/usr/local/lib/python2.7/dist-packages/oct2py-0.3.6-py2.7.egg/oct2py/oct2py.py", line 206, in call
resp = self.eval(cmd, verbose=verbose)
File "/usr/local/lib/python2.7/dist-packages/oct2py-0.3.6-py2.7.egg/oct2py/oct2py.py", line 355, in eval
raise Oct2PyError(msg)
oct2py.utils.Oct2PyError: Tried to run:
"""
load /tmp/tmpMSS6TN.mat "A" "B"
[a_] = c2d(A__, B__)
save "-v6" /tmp/tmpCYcTKT.mat "a__"
"""
Octave returned:
number of columns must match (5 != 3)

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Matthias, can you make the change below to your /usr/local/lib/python2.7/dist-packages/oct2py-0.3.6-py2.7.egg/oct2py/_matread.py and let me know if that fixes it? I made this change when addressing your bug, and then accidentally reverted it prior to release

diff --git a/oct2py/_matread.py b/oct2py/_matread.py
index dd28991..d30fd97 100644
--- a/oct2py/_matread.py
+++ b/oct2py/_matread.py
@@ -94,7 +94,7 @@ class MatRead(object):
                 if "'|O" in str(val.dtype):
                     val = self._get_data(val)
                 if val.size == 1:
-                    val = val.flatten()[0]
+                    val = val.flatten()
         if val.dtype == np.object:
             if len(val.shape) > 2:
                 val = val.T

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that was one small change with a huge effect. Seems to be working now.
I'll report back if I find other errors.

Thank you so much again :+1

{'a': array([[ 1., 1.],
[ 0., 1.]]), 'c': array([[ 1., 0.],
[ 0., 1.]]), 'b': array([[ 1.],
[ 0.]]), 'd': array([[ 0.],
[ 0.]]), 'stname': [u'x_1', u'x_2'], 'tsam': 0.0, 'n': 2.0, 'sys': array([[ 2., 0., 0., 1.]]), 'nz': 0.0, 'outname': [u'y_1', u'y_2'], 'yd': array([[ 0., 0.]]), 'inname': [u'u_1']}
{'a': array([[ 1.64872127, 0.82436064],
[ 0. , 1.64872127]]), 'c': array([[ 1., 0.],
[ 0., 1.]]), 'b': array([[ 0.64872127],
[ 0. ]]), 'd': array([[ 0.],
[ 0.]]), 'stname': [u'x_1_d', u'x_2_d'], 'tsam': 0.5, 'n': 0.0, 'sys': array([[ 2., 0., 0., 1.]]), 'nz': 2.0, 'outname': [u'y_1', u'y_2'], 'yd': array([[ 1., 1.]]), 'inname': [u'u_1']}
{'a': array([[ 1.64872127, 0.82436064],
[ 0. , 1.64872127]]), 'c': array([[ 1., 0.],
[ 0., 1.]]), 'b': array([[ 0.64872127],
[ 0. ]]), 'd': array([[ 0.],
[ 0.]]), 'stname': [u'x_1_d', u'x_2_d'], 'tsam': 0.5, 'n': 0.0, 'sys': array([[ 2., 0., 0., 1.]]), 'nz': 2.0, 'outname': [u'y_1', u'y_2'], 'yd': array([[ 1., 1.]]), 'inname': [u'u_1']}

from oct2py.

Thanks again @MatthiasKauer, this will be in oct2py 0.4.0, forthcoming this weekend.

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