LOG Natural Logarithm Function

Section: Mathematical Functions

Usage

Computes the log function for its argument. The general syntax for its use is 
  y = log(x)

where x is an n-dimensional array of numerical type. Integer types are promoted to the double type prior to calculation of the log function. Output y is of the same size as the input x. For strictly positive, real inputs, the output type is the same as the input. For negative and complex arguments, the output is complex.

Function Internals

Mathematically, the log function is defined for all real valued arguments x by the integral

For complex-valued arguments, z, the complex logarithm is defined as

where arg is the complex argument of z.

Example

The following piece of code plots the real-valued log function over the interval [1,100]: 
--> x = linspace(1,100);
--> plot(x,log(x))
--> xlabel('x');
--> ylabel('log(x)');