ilogb

Calculates <code>logb(x, base=base) + eps</code> where <code>eps</code> is a user-supplied (small) value and
converts the result ala <code>as.integer</code>. The purpose of this function is to avoid
<code>logb</code> variations between platforms. As an example, it is conceivable that <code>logb(32, base=2)</code>
on one platform could return a value of <code>5</code> while on another platform it could return a slightly smaller value,
e.g., <code>4.999999999999999</code>. The difference is due to different compiler and platform-specific implementations of
the S-PLUS or R languages. If <code>logb</code> output is truncated (as is the case with <code>as.integer(logb(x))</code>) then the
result may be unexpected, leading to intractable errors. By adding an appropriate and small value to <code>logb(x)</code>,
subsequent truncation results in consistent value(s) across platforms.

utilities

Insightful Research Tools is a collection of signal processing,
image processing, and time series modeling routines written in the C
language for speed and efficiency. The routines were originally developed at
Insightful for use in S-PLUS.

Stephen Kaluzny

ifultools

Insightful Research Tools

William Constantine

R Core Team 

ilogb function

<dl><dt>x</dt>
<dd>a numeric or complex vector.</dd><dt>base</dt>
<dd>a positive or complex number: the base with respect to which logarithms are computed. Default: <code>2</code>.</dd>
<dt>eps</dt>
<dd>a small numeric value that is added to the <code>logb</code> result prior to truncation via <code>as.integer</code>.
Default: <code>.Machine\$double.eps * 1e9</code>.</dd></dl>

Arguments

Integer truncation of logb output — ilogb

<dl>

<dt>x</dt>
<dd>a numeric or complex vector.</dd>

<dt>base</dt>
<dd>a positive or complex number: the base with respect to which logarithms are computed. Default: <code>2</code>.</dd>


<dt>eps</dt>
<dd>a small numeric value that is added to the <code>logb</code> result prior to truncation via <code>as.integer</code>.
Default: <code>.Machine\$double.eps * 1e9</code>.</dd>

</dl>

ilogb: Integer truncation of logb output

Description

Usage

Value

Arguments

See Also

Examples