Numerical Search with 1-Bit Precision

[thetinman]

I'm trying to do a numerical search and I want to find the number exactly. Here is some code to illustrate my question:

long guessed_number, limit_number = 1000001;

guessed_number = (long)(sqrt(my_output_double) * (double)some_long_int / some_double +0.5);

I want to find the largest value of guessed_number that is not greater than limit_number. I need 1-bit of precision. I'm trying to do a bisection search, but I'm not sure how to maximize the precision. I'm guessing that this must be a classic/standard problem and that references exist, no?

[King Mir]

You just set your terminating condition to be if( abs(last_guess-current_guess) < 0.5).

[thetinman]

I think I phrease that poorly. I'm trying to find the largest possible value of my_output_double that results in a value of guessed_number <= limit_number

[King Mir]

If it's the input variable's precision that you are worried about, then you limit the number of times you loop directly. 1-bit of precision should mean that you do the bisection only once. Of course 1 bit precision is fairly useless. Perhalps you mean integer precision?