In Matlab/octave, when I add two numbers, I am losing some of my digits.
>>> 23.0 + 0.65850
ans = 23.659
How do I get back a double that is 23.65850?
The number is being rounded only for display purposes. Take a look at the format command if you wish to change it.
octave> 23 + 0.65850
ans = 23.659
octave> format free
octave> 23 + 0.65850
ans = 23.7
octave> format long g
octave> 23 + 0.65850
ans = 23.6585
Take a look at help format for the other options but remember, that this only affects the display. You are not losing any precision.
来源：https://stackoverflow.com/questions/13886821/matlab-octave-addition-losing-digits-of-precision