-------FFdecsa-------First, you need to know how decsa works, study the source of a classicalimplementation. Then you have to understand how things are done inslicing mode. Read all the documentation and have a working classicalimplementation to compare partial results. There are comments spreadaround the code. Some things are difficult to understand without papernotes; for example the matrix transpositions and meaning of arrayindices.Sorry, it is hard to understand and modify ...... but it was harder to design and implement!!!