Fast computation of the Hecke operator T_p on weight 2 modular symbols on \Gamma_0(N) for "small" N and "large" p.
The main function is written in C. A Magma interface is provided. It should be easy to adapt this for Sage.
Download the zip-file and unpack it.
Change the path to the C program in the file "EssenModular.m" by hand.
> M := ModularSymbols(360, 2, 1);
> C := CuspidalSubspace(M);
> time T := EssenHeckeOperator(C, NextPrime(10^9));
Last modification: 16 August 2008.