Editing Schönhage–Strassen algorithm (section)

===Pseudocode===

Following algorithm, the standard Modular Schönhage-Strassen Multiplication algorithm (with some optimizations), is found in overview through <ref>{{cite web | year=2014 | page=28 |last1=Lüders |first1=Christoph |title=Fast Multiplication of Large Integers: Implementation and Analysis of the DKSS Algorithm |url=https://www.researchgate.net/publication/273701188}}</ref> 
{{olist
|1= Split both input numbers {{mvar|a}} and {{mvar|b}} into n coefficients of s bits each.
Use at least {{tmath|K + 1}} bits to store them,
to allow encoding of the value {{tmath|2^{K}.}}
|2= Weight both coefficient vectors according to (2.24) with powers of {{mvar|θ}} by performing cyclic
   shifts on them.
|3= Shuffle the coefficients {{tmath|a_i}} and {{tmath|b_j}} .
|4= Evaluate {{tmath|a_i}} and {{tmath|b_j}} . Multiplications by powers of ω are cyclic shifts.
|5= Do {{mvar|n}} pointwise multiplications {{tmath|1=c_k := a_kb_k}} in {{tmath|Z/(2^K + 1)Z}}. If SMUL is used recursively,
   provide {{mvar|K}} as parameter. Otherwise, use some other multiplication function like T3MUL
   and reduce modulo {{tmath|2^{K} + 1}} afterwards.
|6= Shuffle the product coefficients {{tmath|c_k}}.
|7= Evaluate the product coefficients {{tmath|c_k}}.
|8= Apply the counterweights to the {{tmath|c_k}} according to (2.25). Since {{tmath|\theta^{2n} \equiv 1}} it follows that
   {{tmath|\theta^{-k} \equiv \theta^{n-k} }}
|9=  Normalize the {{tmath|c_k}} with {{tmath|1/n \equiv 2^{-m} }} (again a cyclic shift).
|10= Add up the {{tmath|c_k}} and propagate the carries. Make sure to properly handle negative coefficients.
|11= Do a reduction modulo {{tmath|2^{N} + 1}}.
}}
* T3MUL = Toom–Cook multiplication 
* SMUL  = Schönhage–Strassen multiplication
* Evaluate = FFT/IFFT