log, ln, ld

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

Example:

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

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