HP Forum Archive 20

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WP34s quadrature Message #1 Posted by hugh steers on 26 Apr 2011, 5:52 a.m. Hi, the manual says this works like the 15c, but i get no difference when changing (eg) FIX mode size. is there some way of specifying the accuracy - or am i doing something wrong. right now, im getting really appalling results. 2 figures correct, for example.

Re: WP34s quadrature Message #2 Posted by Paul Dale on 26 Apr 2011, 5:54 a.m., in response to message #1 by hugh steers There is no way to change the precision of the integration. We're using a Gauss/Kronrod quadrature with a fixed number of points. It won't be terribly good for "difficult" functions. - Pauli

Re: WP34s quadrature Message #3 Posted by Walter B on 26 Apr 2011, 6:40 a.m., in response to message #1 by hugh steers The manual clearly says "the user interface is as in HP-15C." Nothing more. Walter

Re: WP34s quadrature Message #4 Posted by Marcus von Cube, Germany on 26 Apr 2011, 6:56 a.m., in response to message #3 by Walter B We can add a more sophisticated approach as a user code routine. Any contributions are welcome.

Re: WP34s quadrature Message #5 Posted by Namir on 26 Apr 2011, 7:59 a.m., in response to message #1 by hugh steers If I am not mistaken, the SOLVE and INTEGRATE functions had Professor Kahan as it's mentor. Kahan's philosophy was to push the accuracy to the machine limits and not by a user-defined value. The HP-15C Advanced Functions Handbook has a section "Accuracy of the Function to be Integrated" that specifies the accuracy of the integral, which is basically the accuracy of the function you are integrating. This tells me that if you are integrating a function using an empirical approximation, then expect more error in the integral. Namir Edited: 26 Apr 2011, 8:35 a.m.

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