NAME Tie::Math - Hashes which represent mathematical functions. SYNOPSIS use Tie::Math; tie %fibo, 'Tie::Math', sub { f(n) = f(n-1) + f(n-2) }, sub { f(0) = 0; f(1) = 1 }; # Calculate and print the fifth fibonacci number print \$fibo{5}; DESCRIPTION Defines hashes which represent mathematical functions, such as the fibonacci sequence, factorials, etc... Functions can be expressed in a manner which a math or physics student might find a bit more familiar. It also automatically employs memoization. Multi-variable functions are supported. f() is simply passed two variables (f(X,Y) for instance) and the hash is accessed in the same way (\$func{3,-4}). tie tie %func, 'Tie::Math', \&function; tie %func, 'Tie::Math', \&function, \&initialization; &function contains the definition of the mathematical function. Use the f() subroutine and N index provided. So to do a simple exponential function represented by "f(N) = N**2": tie %exp, 'Tie::Math', sub { f(N) = N**2 }; &initialization contains any special cases of the function you need to define. In the fibonacci example in the SYNOPSIS you have to define f(0) = 1 and f(1) = 1; tie %fibo, 'Tie::Math', sub { f(N) = f(N-1) + f(N-2) }, sub { f(0) = 1; f(1) = 1; }; The &initializaion routine is optional. Each calculation is "memoized" so that for each element of the array the calculation is only done once. While the variable N is given by default, A through Z are all available. Simply import them explicitly: # Don't forget to import f() use Tie::Math qw(f X); There's no real difference which variable you use, its just there for your preference. (NOTE: I had to use captial letters to avoid clashing with the y// operator) AUTHOR Michael G Schwern WHAT IS THIS? This is Tie::Math, a perl module. HOW DO I INSTALL IT? To install this module, cd to the directory that contains this README file and type the following: perl Makefile.PL make make test make install To install this module into a specific directory, do: perl Makefile.PL PREFIX=/name/of/the/directory ...the rest is the same... Please also read the perlmodinstall man page, if available. WHAT ELSE DO I NEED? Perl 5.6.0 and up