log, ln, ld

Compute the logarithm of the argument x element by element.

Usage

log(x , 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)

xa scalar, vector or matrix; all elements must be greater than 0

bthe 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

Note

For the inverse function the operater ^ can be used; e.g.: 10^x, e^x, ...

Example:

#a := eval vv(1,2,3,4,5)
#b := eval init(5,2,0)
#c := eval vmcol($#a, $#b, $#a) 
// -> $#c is a matrix with 4 rows and 5 columns:
//    $#c[*,*] = $#a,  #c[1,*] = $#b[*,0],  $#c[2,*] = $#b[*,1],  $#c[3,*] = $#a

<function list>