Log n Grows Slowly
The function log(n) grows so slowly that it can almost be considered to be the same as 1.
A good rule: log2(1000) ≈ 10, since 210 = 1024.
10 bits ≈ 3 decimal digits.
n | log2(n) | |
students in CS 314 | 240 | 8 |
students at UT | 50,000 | 16 |
people in US | 300,000,000 | 28 |
people on earth | 7,000,000,000 | 33 |
national debt | 19,500,000,000,000 | 45 |
Library of Congress, bytes | 20*1012 | 45 |
earth surface area, mm2 | 5*1020 | 69 |
atoms in universe | 1080 | 266 |
Thus, we can say that log2(n) < 300 for any problem that we are likely to see. If we simply wrote 300 instead of log2(n), our rule tells us to eliminate the constant 300.