René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Compatibility issue with SciPy 1.0","articleBody":"The following snippet\r\n\r\n```python\r\nimport control as ctrl\r\nG = ctrl.tf(1, [1, 1])\r\nt, y = ctrl.step_response(G)\r\n ```\r\n\r\nexecuted under Python 3.5.4 with **SciPy 1.0**, NumPy 1.13.3 and python-control 0.7 and **SlyCot NOT installed** fails to run.\r\n\r\nAfter investigation it turns out that the problem arrises in the file `statesp.py`, function `_convertToStateSpace` line 641: python-control tries to solve the problem using SlyCot. Since SlyCot is not found, it falls back to the `ImportError` handling in which the SciPy's `lti` is called:\r\n```python\r\n            lti_sys = lti(squeeze(sys.num), squeeze(sys.den))\r\n            return StateSpace(lti_sys.A, lti_sys.B, lti_sys.C, lti_sys.D,\r\n                              sys.dt)\r\n```\r\nIn SciyPy versions PRIOR to 1.0 the lti_sys object had the attributes A, B, C, D. However, in SciPy 1.0 these attributes have been removed. Hence, the code fails to execute.\r\n\r\nPossible workaround would be (runs using SciPy 0.19 and 1.0):\r\n```python\r\n            from scipy.signal import tf2ss\r\n            A, B, C, D = tf2ss(squeeze(sys.num), squeeze(sys.den))\r\n            return StateSpace(A, B, C, D, sys.dt)\r\n```\r\n\r\nWhat do you think? Since many Windows user do not have Slycot available by default it would be nice to get this fixed.\r\n\r\nJan","author":{"url":"https://github.com/jcwinkler","@type":"Person","name":"jcwinkler"},"datePublished":"2017-11-15T11:02:46.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/164/python-control/issues/164"}