warning in pade - Printable Version +- HP Forums ( https://www.hpmuseum.org/forum)+-- Forum: HP Calculators (and very old HP Computers) ( /forum-3.html)+--- Forum: HP Prime ( /forum-5.html)+--- Thread: warning in pade ( /thread-2198.html) |

warning in pade - Alberto Candel - 09-28-2014 04:01 PM
Hi, I was working on finding a reasonable expression for a Pade approximation to sin(x). The HP Prime has pade(f(x),x,n,p) which outputs a rational function approximation to f(x) of order less than or equal to n+1 with numerator of degree <p. It works OK, for example pade(sin(x),x,5,4) returns (-7*x^3+60*x)/(3*x^2+60) as expected. But for some values of the parameters n, p, the Prime gives a warning before returning the answer. For example pade(sin(x),x,5,3) shows Solution may be wrong since a and b are not prime together. Does anyone know what is happening? What are a and b? Thanks A. RE: warning in pade - parisse - 09-29-2014 06:33 AM
It means that the extended euclidean algorithm used to solve for Pade approximation returns 2 polynomials that are not prime together, therefore the approxmant will probably loose one or more order. |