Fix issue 1096

.github/workflows/nanopolish.yaml

@@ -1,6 +1,6 @@
 name: nanopolish
 
-on: [ push ]
+on: [ push, workflow_dispatch ]
 
 jobs:
     build-and-test:

README.md

@@ -10,6 +10,8 @@ Software package for signal-level analysis of Oxford Nanopore sequencing data. N
 Presently nanopolish does not support R10.4 flowcells as variant and methylation calling is accurate enough to not require signal-level analysis. We intend to support signal exploration through `eventalign` but do not currently have a timeline for this as our development time is currently dedicated to other projects.
 
 ## Release notes
+* 0.14.1: added the `compare_methylation.py` script from the [methylation example data bundle](warwick.s3.climb.ac.uk/nanopolish_tutorial/methylation_example.tar.gz) to the `nanopolish` package
+
 * 0.14.0: support modification bam files, compile on M1 apple hardware, support [SLOW5](https://github.com/hasindu2008/slow5lib) files
 
 * 0.13.3: fix conda build issues, better handling of VBZ-compressed files, integration of module for [nano-COP](https://www.nature.com/articles/s41596-020-00469-y)
@@ -154,3 +156,10 @@ docker run -v /path/to/local/data/data/:/data/ -it :image_id  ./nanopolish event
 ## Credits and Thanks
 
 The fast table-driven logsum implementation was provided by Sean Eddy as public domain code. This code was originally part of [hmmer3](http://hmmer.janelia.org/). Nanopolish also includes code from Oxford Nanopore's [scrappie](https://github.com/nanoporetech/scrappie) basecaller. This code is licensed under the MPL.
+
+The `scripts/compare_methylation.py` was originally provided in the [example methylation data bundle](warwick.s3.climb.ac.uk/nanopolish_tutorial/methylation_example.tar.gz) which was obtained using:
+```
+curl -O warwick.s3.climb.ac.uk/nanopolish_tutorial/methylation_example.tar.gz
+tar xvfz methylation_example.tar.gz
+ls methylation_example/compare_methylation.py
+```

scripts/compare_methylation.py

@@ -0,0 +1,96 @@
+#! /usr/bin/env python
+
+import sys
+import csv
+import argparse
+
+def make_key(c, s, e):
+    return c + ":" + str(s) + "-" + str(e)
+
+def parse_key(key):
+    return key.replace("-", ":").split(":")
+
+class MethylationStats:
+    def __init__(self, num_reads, num_methylated, atype):
+        self.num_reads = num_reads
+        self.num_methylated_reads = num_methylated
+        self.analysis_type = atype
+
+    def accumulate(self, num_reads, num_methylated):
+        self.num_reads += num_reads
+        self.num_methylated_reads += num_methylated
+
+    def methylation_frequency(self):
+        return float(self.num_methylated_reads) / self.num_reads
+
+def update_stats(collection, key, num_reads, num_methylated_reads, atype):
+    if key not in collection:
+        collection[key] = MethylationStats(num_reads, num_methylated_reads, atype)
+    else:
+        collection[key].accumulate(num_reads, num_methylated_reads)
+
+def load_nanopolish(filename):
+    out = dict()
+    csv_reader = csv.DictReader(open(filename), delimiter='\t')
+
+    for record in csv_reader:
+        key = make_key(record["chromosome"], record["start"], record["end"])
+
+        # skip non-singleton, for now
+        if int(record["num_cpgs_in_group"]) > 1:
+            continue
+
+        num_reads = int(record["called_sites"])
+        methylated_reads = int(record["called_sites_methylated"])
+        out[key] = MethylationStats(num_reads, methylated_reads, "nanopolish")
+
+    return out
+
+def load_bisulfite(filename):
+    out = dict()
+    fh = open(filename)
+    for line in fh:
+        fields = line.rstrip().split()
+        chromosome = fields[0]
+        start = int(fields[1])
+        end = int(fields[2])
+        strand = fields[5]
+        num_reads = float(fields[9])
+        percent_methylated = float(fields[10])
+        methylated_reads = int( (percent_methylated / 100) * num_reads)
+        key = ""
+
+        # accumulate on forward strand
+        if strand == "+":
+            key = make_key(chromosome, str(start), str(start))
+        else:
+            key = make_key(chromosome, str(start - 1), str(start - 1))
+
+        update_stats(out, key, num_reads, methylated_reads, "bisulfite")
+
+    return out
+
+# Load the file of methylation frequency based on the filename
+def load_methylation(filename):
+    if filename.find("bisulfite") != -1:
+        return load_bisulfite(filename)
+    else:
+        return load_nanopolish(filename)
+
+set1 = load_methylation(sys.argv[1])
+set2 = load_methylation(sys.argv[2])
+
+output = 0
+print("key\tdepth_1\tfrequency_1\tdepth_2\tfrequency_2")
+for key in set1:
+    if key in set2:
+
+        d1 = set1[key]
+        d2 = set2[key]
+
+        if d1.num_reads == 0 or d2.num_reads == 0:
+            continue
+        print("%s\t%d\t%.4f\t%d\t%.4f" % (key, d1.num_reads, d1.methylation_frequency(), d2.num_reads, d2.methylation_frequency()))
+        output += 1
+
+sys.stderr.write("set1 sites: %d set2 sites: %d output: %d\n" % (len(set1), len(set2), output))