Figure 2

Flowchart for iterative computation of probabilities of base pairing and extrinsic information. The pairwise coincidence probabilities are computed once during initialization. Iteration t starts with computation of the extrinsic information for the sequences, utilizing the base pairing probabilities computed in the previous iteration. Note that the extrinsic information computation for a sequence at iteration t does not utilize its own base pairing probabilities computed at iteration (t - 1). This is shown in the figure by an '×' symbol between the arrow that represents the base pairing probability of the sequence and the extrinsic information computation block for the sequence. The first iteration starts with initialization of extrinsic information of each sequence to 1. (η + 1) total iterations are performed.