John Cremona on Fri, 06 Nov 2015 12:13:37 +0100 |
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real polynomials |
I am using the library functions sturm() and sturmpart() to get the number of real roots of a real polynomial in the whole real line or just the positive or negative half-lines. But occasionally it fails with *** domain error in polsturm: issquarefree(pol) = 0 which I expect is only happening if the discriminant is exactly 0. Is that right? Is there a reliable way of taking the squarefreepart, or the radical, or a real polynomial? It is in fact true that in my program the polynomial coefficients are always rational with denominator a power of 2, so will be known exactly. I would like to avoid having to keep track of the denominators and using (scaled) integer coefficients. John