René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Casting complex number to float","articleBody":"Code to reproduce the problem:\n```python3\nsys = ctrl.zpk([], [1j], 1)\n\nplt.figure(figsize=(8, 6))\nctrl.root_locus(sys, color='red') #\u003c-- Problem is here\n\nplt.xlabel('Real Axis (σ)')\nplt.ylabel('Imaginary Axis (jω)')\nplt.grid(True)\nplt.show()\n```\n\nIn the diagram, you can see the pole is placed at the wrong location. but I looked into it and found a quick solution (though I am not familiar with the code, and it might be deeper than I found)\n\nin the files xferfcn.py (lines 1068, and 1072) there are two arrays that are created of type `float`, that could later assigned to complex numbers if the input is of type `complex`. the fix is to just change the type of the array to `complex`\n\nThen another issue arises in plocus.py (line 267), if the coefficients are complex, it is again casted into a float. I am not sure what this value is used for, but I believe this can be fixed by casting the input type to complex if it isn't already, then using the magnitude of the complex number instead of casting it, which I believe the abs() function will do for default python `complex` types.\n\nShould be an easy fix, hope this helps","author":{"url":"https://github.com/Master-Pr0grammer","@type":"Person","name":"Master-Pr0grammer"},"datePublished":"2025-03-21T03:56:39.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/1141/python-control/issues/1141"}