These functions compute integer approximations to logarithms of x. They are  based on the IEEE function logb.

The ilog[b](x) function approximates the integer base b logarithm, where the default base is exp(1).

You can enter the command ilog[b] using either the 1-D or 2-D calling sequence. For example, ilog[2](50) is equivalent to ${\mathrm{ilog}}_2\left(50\right)$.

If x is real, ilog[b](x) returns r such that $b^r\le \left|x\right|<b^{r+1}$.

The ilog2(x) function returns the integer base 2 logarithm of x.

If x is real and r = ilog2(x), then r is either an exact integer or special symbolic value, and $2^r\le \left|x\right|<2^{r+1}$.

If x is a complex numeric, ilog2(x) returns  max(ilog2(Re(x)), ilog2(Im(x))).

If x is a special symbolic value, the indicated result is returned.

The ilog10(x) function returns the integer base 10 logarithm of x.

If x is real, ilog10(x) returns r such that r is either an exact integer or special symbolic value, and${10}^r\le \left|x\right|<{10}^{r+1}$.

If x is a complex numeric, ilog10(x) returns  max(ilog10(Re(x)), ilog10(Im(x))).

If x is a special symbolic value, the indicated result is returned.

The computation of ilog2(x) and ilog10(x) is more efficient than ilog[b](x), b <> 2, 10.

The ilog2 and ilog10 commands are thread-safe as of Maple 15.

For more information on thread safety, see index/threadsafe.

$\mathrm{ilog10}\left(x\right)$

$\mathrm{ilog10}\left(x\right)$

$\mathrm{ilog10}\left(150\right)$

$2$

$\mathrm{ilog10}\left({10}^{-37}\right)$

$\mathrm{-37}$

$\mathrm{ilog10}\left(2^{14}\&plus;3^{10}I\right)$

$4$

$\mathrm{ilog2}\left(50\right)$

$5$

${\mathrm{ilog}}_2\left(2^8\right)$

$8$

${\mathrm{ilog}}_3\left(10\right)$

$2$

${\mathrm{ilog}}_{\&ExponentialE;}\left(3\right)$

$1$