Mathematical Operations: Mathematical Functions

## powoftwo, logbtwo

**powoftwo**(x) (init-rate or control-rate args only)
**logbtwo**(x) (init-rate or control-rate args only)

### Description

Power-of-two operations.

### Performance

**powoftwo**() function returns 2 ^ *x* and allows positive and negatives numbers as argument. The range of values admitted in **powoftwo**() is -5 to +5 allowing a precision more fine than one cent in a range of ten octaves. If a greater range of values is required, use the slower opcode **pow**.

**logbtwo**() returns the logarithm base two of *x*. The range of values admitted as argument is .25 to 4 (i.e. from -2 octave to +2 octave response). This function is the inverse of **powoftwo**().

These functions are fast, because they read values stored in tables. Also they are very useful when working with tuning ratios. They work at i- and k-rate.

### Authors

Gabriel Maldonado

Italy

June, 1998

John ffitch

University of Bath, Codemist, Ltd.

Bath, UK

July, 1999

New in Csound version 3.57

Mathematical Operations: Mathematical Functions