A built-in function is part of the MATLAB executable. MATLAB does not implement these functions in the MATLAB language. Although most built-in functions have a .m file associated with them, this file only supplies documentation for the function. The source code detailing the implementation of built-in functions is confidential and proprietary information of MathWorks, Inc. We cannot send the source code to customers. However, some details about the algorithms used for many of these functions, including EIG and FFT, are available in the help documentation. Please type:
from the MATLAB command prompt.
If you are interested in the RAND or RANDN functions, you can read more information about them in two Cleve's Corner articles available at the following locations: