Oops. Make that croots3.py (<http://www.rcblue.com/Python/croots3.py>). I forgot a couple of abs's. For example,
"if n.imag < 1e-13:" is changed to "if abs(n.imag) < 1e-13:"
Dick
Dick Moores wrote at 07:38 12/10/2004:
I've modified croots.py to croots2.py (<http://www.rcblue.com/Python/croots2.py>)
The only changes are in the testCrootsResult function. It will ignore very small .imag or .real when printing.
Thus this result: ================================ Enter either a complex number in form x + yj, or a real number: 4 Enter an integer n, to find the n'th roots of that number: 3 c is (4+0j); n is 3
root1 is 1.58740105197, adjusted from (1.58740105197+0j) root1 to the 3 power is 4.0, adjusted from (4+0j)
root2 is (-0.793700525984+1.374729637j) root2 to the 3 power is 4.0, adjusted from (4-2.6645352591e-015j)
root3 is (-0.793700525984-1.374729637j) root3 to the 3 power is 4.0, adjusted from (4-5.55111512313e-015j) ====================================
Dick
Dick Moores wrote at 02:15 12/10/2004:Aw, that's just amazing.
I put your function in http://www.rcblue.com/Python/croots.py, which gets c and n from user and adds a test function.
Here's what one run produces:
==================================== Enter either a complex number in form x + yj, or a real number: 3.1 -1j Enter an integer n, to find the n'th roots: 5 c is (3.1-1j); n is 5
root1 is (1.26393645827-0.0789828505298j) root1 to the 5 power is (3.1-1j)
root2 is (0.465695000088+1.17766796174j) root2 to the 5 power is (3.1-1j)
root3 is (-0.976121119826+0.806821678349j) root3 to the 5 power is (3.1-1j)
root4 is (-1.06897102928-0.679024741664j) root4 to the 5 power is (3.1-1j)
root5 is (0.315460690744-1.2264820479j) root5 to the 5 power is (3.1-1j) ======================================
Actually, I'm trying to write a Python script that computes all 3 roots of a cubic equation. Do you happen to have one tucked away in your store of wisdom and tricks? (One for real coefficients will do).
Anyway, thought it wouldn't hurt to ask..
Dick
Tim Peters wrote at 07:41 12/9/2004:Try this instead:
def croots(c, n): """Return list of the n n'th roots of complex c.""" from math import sin, cos, atan2, pi
arg = abs(c)**(1.0/n) theta = atan2(c.imag, c.real) result = [] for i in range(n): theta2 = (theta + 2*pi*i)/n x = arg * cos(theta2) y = arg * sin(theta2) result.append(complex(x, y)) return result
_______________________________________________ Tutor maillist - [EMAIL PROTECTED] http://mail.python.org/mailman/listinfo/tutor
_______________________________________________ Tutor maillist - [EMAIL PROTECTED] http://mail.python.org/mailman/listinfo/tutor
