Figure 3
From: Multithreaded comparative RNA secondary structure prediction using stochastic context-free grammars
Division of calculations in the inside-outside algorithm. In order to apply the bifurcation rules of the grammar to the cell marked in black, the inside algorithm requires the values in the red cells to be known (from nonterminals L (vertical) and S (diagonal)). The products of values in cells of the same shade of red are added to the value in the black cell. Thick blue lines illustrate the defined sector boundaries, for a choice of divisions where the dimension of each sector is 3. All sectors have the same size; points that lie outside the region to be calculated (for example, negative subsequence lengths) are stored but ignored in the calculations.