Re: A problem with range objects and floating point numbers

[Daniel J Sebald]

I had a mistake in the example script.  The norm for the second example 
(result(i) = base + i*increment) actually has a smaller norm, but still 
greater than interpolating algorithm.

Dan


octave:106> range_test_benchmark = str2num(sprintf('%.1f ',linspace(-2, 
.1, 22)));
octave:107> range_test10 = linspace (-20, 1, 22) * .1;
octave:108> norm(range_test10 - range_test_benchmark)
ans =    4.7429e-16
octave:109> range_test11 = linspace (-2, .1, 22);
octave:110> norm(range_test11 - range_test_benchmark)
ans =    4.3088e-16
octave:111> A = -2;
octave:112> B = .1;
octave:113> N = 22;
octave:114> for (i=1:1:N)
>   range_test12(i)=(A*(N-i) + B*(i-1))/(N-1);
> endfor
octave:115> norm(range_test12 - range_test_benchmark)
ans =    3.3422e-16
octave:116> [range_test10' range_test11' range_test12'] - 
range_test_benchmark'*[1 1 1]
ans =

   0.0000e+00   0.0000e+00   0.0000e+00
  -2.2204e-16   0.0000e+00   0.0000e+00
   0.0000e+00   0.0000e+00   2.2204e-16
  -2.2204e-16   0.0000e+00  -2.2204e-16
   0.0000e+00   0.0000e+00   0.0000e+00
   0.0000e+00   0.0000e+00   0.0000e+00
  -2.2204e-16   0.0000e+00   0.0000e+00
   0.0000e+00   2.2204e-16   0.0000e+00
  -2.2204e-16   0.0000e+00   0.0000e+00
   0.0000e+00   0.0000e+00   0.0000e+00
   0.0000e+00   0.0000e+00   0.0000e+00
   0.0000e+00   1.1102e-16   1.1102e-16
   0.0000e+00   2.2204e-16   0.0000e+00
  -1.1102e-16   0.0000e+00   0.0000e+00
  -1.1102e-16   1.1102e-16   0.0000e+00
   0.0000e+00   0.0000e+00   0.0000e+00
   0.0000e+00   1.1102e-16   0.0000e+00
  -5.5511e-17   1.6653e-16   0.0000e+00
   0.0000e+00   5.5511e-17   0.0000e+00
   0.0000e+00   1.3878e-16   2.7756e-17
   0.0000e+00   0.0000e+00   0.0000e+00
   0.0000e+00   0.0000e+00   0.0000e+00