WP34S : is this result "zero" enough ?  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: WP34S : is this result "zero" enough ? (/thread192695.html) 
WP34S : is this result "zero" enough ?  Miguel Toro  09012011 Hola, I am still playing with the 15c examples and this time it is from the advanced functions handbook, page 78, calculating the nth roots of a complex number. I tried my best to translate the program, so here is my WP34s version:
001 LBL A to run it, I first set the ssize8, then 0 FILL and then follow the example in the book, using 1^1/100 as the value. Here are the results:
k = 0, z0 = 1 (check!) So, is this because the different precision between both machines and this is the good result? ... or am I that bad as a programer :) Saludos, Miguel
Edited: 1 Sept 2011, 8:41 p.m.
Re: WP34S : is this result "zero" enough ?  Marcus von Cube, Germany  09022011 Miguel, you could try the various rounding modes (RM) which affect how the internal high precision numbers are rounded. The e38 looks very much like a rounding artifact because the internal precision is in this range.
Looking more closely at your code I see you do calculate the inverse of the exponent and later multiply it by k. This may lead to different results then computing k/n. Edited: 2 Sept 2011, 2:27 a.m.
Re: WP34S : is this result "zero" enough ?  Paul Dale  09022011 Without having investigated specifically, the 10^{38} result you are seeing is around the internal precision used for calculations. My guess would be a slight rounding issue is present here. Probably in the polar to rectangular conversion.
Re: WP34S : is this result "zero" enough ?  Miguel Toro  09022011 I think the rounding issue may come from the y^x. I tried this simple example with (1+i)^2: 1, ENTER, 1, 0, ENTER, 2, CPX, Y^X = (7,5998)^39 + 2i In both cases the 15c and 42s give 2i as the result, either with y^x or x^2. I tried the RM command (thanks for calling me geek :))and it did not make any difference. As you say, it is close enough to zero. Thanks,
Migue
Re: WP34S : is this result "zero" enough ?  Paul Dale  09052011 Quote: The RM modes only change how an internal high precision number is rounded to a sixteen digit register, not how rounding takes place during internal high precision calculations.
