Consensus peaks

A consensus peak is created on a position of genome where is covered by at least one peak from the output sets of the processed replicates. Accordingly, a consensus peak has the following characteristics:

• Coordinate (i.e., chromosome, start, and stop)
  The coordinate of a consensus peak is the union of the coordinates of the peaks from output sets which overlap that position on the genome. For instance:

    // From the Output set of Replicate 1 
    chr1    10    20    macs_peak_1    20.9
  
    // From the Output set of Replicate 2 
    chr1    15    25    macs_peak_1    14.6
  
    // The resulting consensus peak 
    chr1    10    25    mspc_peak_1    163.484
  Note that the p-values are in `-log10` format. 

• Value
  The value of each consensus peak is X^2 which is calculated by combining the p-values of the overlapping peaks using Fisher's combined probability test:

    X_i^2 = -2 \times \sum_{i=1}^k \ln(p_i)

where X_i^2 is the value of consensus peak i, and p_i is the p-value of overlapping peaks. For instance, the X^2 of aforementioned consensus peaks is 163.484, which is calculated by combining the p-values of overlapping peaks (i.e., 20.9 and 14.6) using the Fisher's method.