log, ln, ld

From STX Wiki
Jump to navigation Jump to search

Compute the logarithm of the argument x element by element.

Usage
log(x , b) general logarithm to base b
log(x) common logarithm (base 10)
ln(x) natural logarithm (base e) alias: log(x,e)
ld(x) logarithm to the base 2 alias: log(x,2)
x
a scalar, vector or matrix; all elements must be greater than 0
b
the base of the logarithm; must be a positive number
Result
The result r has the same type as x and contains the logarithm of x to the specified base b, computed element by element.
See also
npow2, exp, lin2log, log2lin
Note
For the inverse function use the operater ^ or the function exp; e.g.: 10^x, e^x, ...

<function list>


Example:

#a := eval 20*log(2)     // convert factor 2 to 6dB
#b := eval 20*log(2,10)  // same as above
#c := eval 20*log(vv(2,10,20,50,100))
// $#c = { 6.02, 20, 26.02, 33.98, 40 }