René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Unsupported NumPy datatype complex128","articleBody":"Dear developers,\n\nI've encountered what could be an unintentional exception (TypeError). This MWE codesnippet:\n```\nimport numpy as np\nimport control as cm\n\nP = cm.rss(5)\nq1 = cm.zpk(zeros=P.zeros().astype(np.complex64), \n            poles=P.poles().astype(np.complex64), \n            gain=1, dt=0)\n\nq2 = cm.zpk(zeros=P.zeros().astype(np.complex128),\n            poles=P.poles().astype(np.complex128),\n            gain=1, dt=0)\n```\noutputs (sometimes only on the 2nd execution):\n```\nTraceback (most recent call last):\n  File \"...\\scratch.py\", line 9, in \u003cmodule\u003e\n    q2 = cm.zpk(zeros=P.zeros().astype(np.complex128),\n                poles=P.poles().astype(np.complex128),\n                gain=1, dt=0)\n  File \"...\\Local\\Programs\\Python\\Python313\\Lib\\site-packages\\control\\xferfcn.py\", line 1819, in zpk\n    return TransferFunction(num, den, *args, **kwargs)\n  File \"...\\Local\\Programs\\Python\\Python313\\Lib\\site-packages\\control\\xferfcn.py\", line 207, in __init__\n    num = _clean_part(num, \"numerator\")\n  File \"...\\Local\\Programs\\Python\\Python313\\Lib\\site-packages\\control\\xferfcn.py\", line 2005, in _clean_part\n    raise TypeError(\n        f\"unsupported data type: {type(out[i, j][k])}\")\nTypeError: unsupported data type: \u003cclass 'numpy.complex128'\u003e\n```\n\nFrom the top of my head, I can't think of a reason why 4 byte complex numbers are allowed, but 8 bytes aren't. If there is, please enlighten me!\n\nHowever, I think there are more incompatibilities between NumPy and this xferfcn.py file, because executing\n`print(q1)`\nyields\n```\nFile \"...\\scratch.py\", line 13, in \u003cmodule\u003e\n    print(q1)\n    ~~~~~^^^^\n  File \"...\\Local\\Programs\\Python\\Python313\\Lib\\site-packages\\control\\xferfcn.py\", line 447, in __str__\n    denstr = _tf_polynomial_to_string(\n        self.den_array[no, ni], var=var)\n  File \"...\\Local\\Programs\\Python\\Python313\\Lib\\site-packages\\control\\xferfcn.py\", line 1366, in _tf_polynomial_to_string\n    coeffs = eval(repr(coeffs))\n  File \"\u003cstring\u003e\", line 2, in \u003cmodule\u003e\nNameError: name 'float32' is not defined. Did you mean: 'float64'?\n```\n\nPackage versions:\nnumpy==2.2.6\ncontrol==0.10.2\n\nKind regards,\nSachin\n","author":{"url":"https://github.com/sachinumans","@type":"Person","name":"sachinumans"},"datePublished":"2025-11-24T09:07:49.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/1188/python-control/issues/1188"}