# log2

## Returns the log base 2 of n, the number 2 must
be powered by to equal n.

**Syntax:**

log2(n);

Argument |
Description |

n |
The input value. |

**Returns:** Real

### Description

This function basically asks "how many 2's do you need to
multiply to get n?". A common example of use in programming would
be to calculate the number of bits that are needed to represent a
number. To do this we calculate the `log2(x)` of the number,
round it down and add 1 - for example `log2(100)` returns
6.643856, which rounded down is 6, to which we add one and it gives
us 7. So we need 7 bits to represent 100. It can also be used for
describing exponential growth or decay, and is often called a
*binary logarithm*.

### Example:

colourbits = floor(log2(colour)) - 1;

The above code stores the number of bits needed to represent the
value stored in the variable "colour".

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