Members of the Forum -

If I'm approximating, e.g. the square root of 3, with a matrix method which
returns an extended precision numerator and denominator, when I work out the
decimal equivalent of this, at what point do I run out of significant
digits?

For example,

   (1 3,:1 1)&(+/ .*)^:(5+i.5)],.1 0  NB. Successive approximations of %:3
  76
  44

 208
 120

 568
 328

1552
 896

4240
2448
   (%:3)-%/(1 3,:1 1)&(+/ .*)^:10],.x: 1 0  NB. How far off are successive
approximations?
_6.6086991e_6
   (%:3)-%/(1 3,:1 1)&(+/ .*)^:20],.x: 1 0
_1.2607915e_11
   (%:3)-%/(1 3,:1 1)&(+/ .*)^:30],.x: 1 0
_2.220446e_16
   (%:3)-%/(1 3,:1 1)&(+/ .*)^:40],.x: 1 0  NB. More than 16 digits
0
   (1 3,:1 1)&(+/ .*)^:40],.x: 1 0    NB. How precise is this in decimal?
144052522725670912
 83168762773110784
   2^.(1 3,:1 1)&(+/ .*)^:40],.x: 1 0 NB. Bits/number - relevant?
56.999373
56.206891

>From the progression of exponents in the cases for 10, 20, and 30
iterations, I'm guessing the answer should be about 21 significant digits
but is there a way to better quantify this?

Thanks,

Devon
-- 
Devon McCormick, CFA
^me^ at acm.
org is my
preferred e-mail
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