Solving the diophantine equation ax2+bxy+cy2=n, where b2-4ac > 0 and is not a perfect square, n non-zero, gcd(a,b,c)=1
This uses a continued fraction approach to find representatives of the equivalence classes of solutions (x,y) with gcd(x,y)=1. The method goes back to Lagrange 1770 and was rediscovered in 2001 by Keith Matthews.
If gcd(a,n)=1, the algorithm finds representatives with least positive y.
(See paper.)
The standard method is due to Gauss (See G.B. Mathews Number Theory, page 97 or note.)
E = 1 is verbose.
Last modified 1st October 2006
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