There is a small bug in the bed2wig.py
In clusters function:

Code:

If we're on a new chromosome, reset everything.

    if chrom != last_chrom:
        if verbose:
            sys.stderr.write('%s\n'%chrom)
        features = []
        cluster_start = start
        cluster_stop = stop
    last_chrom = chrom 

It reset everything but forgot to return the final cluster of last chromosome
So the final cluster of each chromosome is missed whenever we meet a new chromosome
A small toy can prove this :
chr1 1 100 * * +
chr2 1 100 * * +
you can only find chr2 in the wig file~