===== Natural Logarithm ======

==== ln( a ) ====

Return the natural logarithm of a.

=== Description ===

<code>ln( a )</code>

Returns the natural logarithm (base-e logarithm) of a.

=== Parameters ===

| ''a'' | Value |

=== Return value ===

This function returns natural logarithm of a.

=== Example usage ===

<code>ln( 20 )</code>

Returns 2.9957...