ASA063 is a MATLAB program, using double precision arithmetic, which evaluates the incomplete Beta function.
ASA063 is Applied Statistics Algorithm 63. Source code for many Applied Statistics Algorithms is available through STATLIB.
ASA063 is also available in a C++ version and a FORTRAN77 version and a FORTRAN version.
ASA109 is a MATLAB library which inverts the incomplete Beta function.
ASA226 is a MATLAB library which evaluates the CDF of the noncentral Beta distribution.
BETA_NC is a FORTRAN90 library which evaluates the CDF of the noncentral Beta distribution.
TEST_VALUES is a MATLAB library which stores a few values of various mathematical functions.
TOMS179 is a FORTRAN90 library which evaluates the incomplete Beta function.
TOMS708 is a FORTRAN90 library which evaluates the incomplete Beta function.
You can go up one level to the MATLAB source codes.