Will Galway on Wed, 2 Aug 2000 14:02:31 -0500 (CDT)


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Inefficient "solve" in Pari 2.0.18 (beta) ?


The online documentation for "solve" says that Brent's method is used, 
but the behavior is more like simple bisection, even for what I would
consider to be very nice functions.  Try, for example

 testfunc(x) = print(x); sin(x)
 solve(x= -0.1, 0.2, testfunc(x))

or

 testfunc(x) = print(x); x^2-1
 solve(x= 0.8, 1.1, testfunc(x))

working with (default) 28-digit precision.

Thanks.

--Will
( mailto:galway@math.uiuc.edu  http://www.math.uiuc.edu/~galway )