[Maxima] proposal to cut out romberg and quanc8 functions
raymond.toy at ericsson.com
Wed Jan 3 10:08:11 CST 2007
>>>>> "Robert" == Robert Dodier <robert.dodier at gmail.com> writes:
Robert> On 1/3/07, Michel Van den Bergh <michel.vandenbergh at uhasselt.be> wrote:
>> I assume the nesting can be achieved with the new functions using some
>> kind of lambda construct...
Robert> Yes, a lambda expression has the expected effect here.
Robert> quad_qags (lambda ([y], quad_qags (lambda ([x], x^2 + y^2), x, 0,
Robert> y)), y, 0, 1);
Robert> => [.3333333333333333, 3.70074341541719E-15, 21, 0]
Just a note for the unwary: The error estimate produced here
(3.7e-15) is probably way off because it doesn't take into account the
error produced by the inner quad_qags.
One nice thing about having converted the code to Lisp instead of
using an FFI: You might not be able to do nested calls like this with
the original Fortran code because recursive calls like this are
unspecified or forbidden in Fortran 77. I think the quadpack manual
actually gives an example of this, but specifically mentions that two
different integrators are used.
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