Hi there! I've got a really simple task of finding the rank of a matrix of *integers*. NumPy's matrix_rank() appeared to use floats internally (and gave a clearly wrong answers when the matrix contained both small and huge coefficients like 1 and 10**16), so I decided to try SymPy instead. Unfortunately, I found it pretty much impossible to find the rank of a dense matrix of size 30×30 (and above), since it took forever. I timed it and found out that runtime grows *exponentially* (which is really mysterious for me).
Am I doing something wrong? Is there a better way? Here's a trivial example of what I do. PS C:\> python -m timeit -s "import sympy" "sympy.*randMatrix(10).rank()*" 20 loops, best of 5: *13 msec* per loop PS C:\> python -m timeit -s "import sympy" "sympy.*randMatrix(15).rank()*" 5 loops, best of 5: *47.7 msec* per loop PS C:\> python -m timeit -s "import sympy" "sympy.*randMatrix(20).rank()*" 1 loop, best of 5: *2.26 sec* per loop And here's the plot for matrix sizes up to 20 (horizontal axis) with time in seconds. [image: ranktime.png] Thanks for any help or explanation! Cheers! Oleg -- You received this message because you are subscribed to the Google Groups "sympy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sympy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sympy/8922d16f-6771-434e-8cb0-dc1825c6f2a9n%40googlegroups.com.
