integrating trig functions with large constants, exponent out of range
Subject: integrating trig functions with large constants, exponent out of range
From: Raymond Toy
Date: Tue, 09 Jan 2007 09:50:44 -0500
>>>>> "Neilen" == Neilen Marais <nmarais at sun.ac.za> writes:
Neilen> Richard,
Neilen> On Fri, 05 Jan 2007 21:05:51 -0800, Richard Fateman wrote:
>> The Risch algorithm, which should not be called here, is apparently being
>> called. It would perhaps not happen if %i were not there.
Neilen> Removing %i results in a similarly slow integration. Is there any other
Neilen> way I can force Maxima not to use the Risch algorithm?
Maxima calls the Risch integrator when the arg of the trig function is
not a plain variable.
It might be possible to add another test to MONSTERTRIG (responsible
for handling messy trig integrands) so that if the trig arg is of the
form a*x to try the substitution y = a*x and integrate that. If it
succeeds, we're done; if not, call the Risch integrator.
This requires knowledge of Lisp to do, though.
Ray