def __init__(self):
self.guided_ends = False
self.guided_assembly = False
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.start_sites = set()
self.stop_sites = set()
self.expr_data = None
self.node_bounds = None
self.G = None
def __init__(self):
self.guided_ends = False
self.guided_assembly = False
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.start_sites = set()
self.stop_sites = set()
self.expr_data = None
self.node_bounds = None
self.G = None
def _add_transfrags(self, transfrags):
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
for t in transfrags:
if self.chrom is None:
self.chrom = t.chrom
elif self.chrom != t.chrom:
raise TacoError('chrom mismatch')
if self.strand is None:
self.strand = t.strand
elif self.strand != t.strand:
raise TacoError('strand mismatch')
if self.start is None:
self.start = t.start
else:
self.start = min(t.start, self.start)
if self.end is None:
self.end = t.end
else:
self.end = max(t.end, self.end)
if t.is_ref:
self.ref_start_sites.add(t.txstart)
self.ref_stop_sites.add(t.txstop)
self.ref_transfrags.append(t)
else:
self._add_to_interval_trees(t)
self.transfrags.append(t)
self.ref_start_sites = sorted(self.ref_start_sites)
self.ref_stop_sites = sorted(self.ref_stop_sites)
def _add_transfrags(self, transfrags):
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
for t in transfrags:
if self.chrom is None:
self.chrom = t.chrom
elif self.chrom != t.chrom:
raise TacoError('chrom mismatch')
if self.strand is None:
self.strand = t.strand
elif self.strand != t.strand:
raise TacoError('strand mismatch')
if self.start is None:
self.start = t.start
else:
self.start = min(t.start, self.start)
if self.end is None:
self.end = t.end
else:
self.end = max(t.end, self.end)
if t.is_ref:
self.ref_start_sites.add(t.txstart)
self.ref_stop_sites.add(t.txstop)
self.ref_transfrags.append(t)
else:
self._add_to_interval_trees(t)
self.transfrags.append(t)
self.ref_start_sites = sorted(self.ref_start_sites)
self.ref_stop_sites = sorted(self.ref_stop_sites)
class SpliceGraph(object):
def __init__(self):
self.guided_ends = False
self.guided_assembly = False
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.start_sites = set()
self.stop_sites = set()
self.expr_data = None
self.node_bounds = None
self.G = None
@staticmethod
def create(transfrags, guided_ends=False, guided_assembly=False):
self = SpliceGraph()
self.guided_ends = guided_ends
self.guided_assembly = guided_assembly
self._add_transfrags(transfrags)
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
return self
def recreate(self):
self._add_transfrags(chain(self.transfrags, self.ref_transfrags))
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
def _add_transfrags(self, transfrags):
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
for t in transfrags:
if self.chrom is None:
self.chrom = t.chrom
elif self.chrom != t.chrom:
raise TacoError('chrom mismatch')
if self.strand is None:
self.strand = t.strand
elif self.strand != t.strand:
raise TacoError('strand mismatch')
if self.start is None:
self.start = t.start
else:
self.start = min(t.start, self.start)
if self.end is None:
self.end = t.end
else:
self.end = max(t.end, self.end)
if t.is_ref:
self.ref_start_sites.add(t.txstart)
self.ref_stop_sites.add(t.txstop)
self.ref_transfrags.append(t)
else:
self._add_to_interval_trees(t)
self.transfrags.append(t)
self.ref_start_sites = sorted(self.ref_start_sites)
self.ref_stop_sites = sorted(self.ref_stop_sites)
def _compute_expression(self):
expr_data = np.zeros(self.end - self.start, dtype=FLOAT_DTYPE)
for t in self.transfrags:
for exon in t.exons:
astart = exon.start - self.start
aend = exon.end - self.start
expr_data[astart:aend] += t.expr
return expr_data
def _find_node_boundaries(self):
node_bounds = set((self.start, self.end))
node_bounds.update(self.start_sites)
node_bounds.update(self.stop_sites)
# nodes bounded by regions where expression changes to/from zero
node_bounds.update(find_threshold_points(self.expr_data, self.start))
# nodes bounded by introns
for t in self.transfrags:
node_bounds.update(t.itersplices())
if self.guided_ends or self.guided_assembly:
for t in self.ref_transfrags:
if self.guided_ends:
node_bounds.update((t.start, t.end))
if self.guided_assembly:
node_bounds.update(t.itersplices())
return array('i', sorted(node_bounds))
def get_path(self, t):
node_id_map = self.G.graph['node_id_map']
nodes = [node_id_map[n] for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
return tuple(nodes)
def _create_splice_graph2(self):
G = SGraph()
for t in sgraph.itertransfrags():
nodes = [n for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
G.add_path(nodes, t.is_ref)
return G
def _create_splice_graph(self):
'''returns networkx DiGraph object'''
G = nx.DiGraph()
node_bounds = self.node_bounds
node_id_map = {}
id_node_map = {}
current_id = 2
for t in self.itertransfrags():
# split exons that cross boundaries and get the
# nodes that made up the transfrag
nodes = []
for n in split_transfrag(t, node_bounds):
n = Exon(*n)
if n not in node_id_map:
n_id = current_id
current_id += 1
node_id_map[n] = n_id
id_node_map[n_id] = n
else:
n_id = node_id_map[n]
nodes.append(n_id)
if t.strand == Strand.NEG:
nodes.reverse()
# add nodes/edges to graph
u = nodes[0]
SGNode.add(G, u, id_node_map[u], is_ref=t.is_ref)
for i in xrange(1, len(nodes)):
v = nodes[i]
SGNode.add(G, v, id_node_map[v], is_ref=t.is_ref)
G.add_edge(u, v)
u = v
G.graph['node_id_map'] = node_id_map
G.graph['id_node_map'] = id_node_map
return G
def _mark_start_stop_nodes(self):
G = self.G
# get all leaf nodes
for n, nd in G.nodes_iter(data=True):
if G.in_degree(n) == 0:
nd[SGNode.IS_START] = True
if G.out_degree(n) == 0:
nd[SGNode.IS_STOP] = True
# mark change points
change_points = set()
change_points.update(
set((SGNode.IS_START, x) for x in self.start_sites))
change_points.update(set((SGNode.IS_STOP, x) for x in self.stop_sites))
if self.guided_ends:
change_points.update(
(SGNode.IS_START, x) for x in self.ref_start_sites)
change_points.update(
(SGNode.IS_STOP, x) for x in self.ref_stop_sites)
node_bounds = self.node_bounds
strand = self.strand
node_id_map = G.graph['node_id_map']
for direction, pos in change_points:
if ((direction == SGNode.IS_STOP and strand == Strand.NEG) or
(direction == SGNode.IS_START and strand != Strand.NEG)):
bisect_func = bisect.bisect_right
else:
bisect_func = bisect.bisect_left
i = bisect_func(node_bounds, pos)
n = (node_bounds[i - 1], node_bounds[i])
if n in node_id_map:
# 2/5/2016: observed case where trimming caused an interval
# with zero expression, and this function then crashed when
# attempting to mark the node as a start/stop. We no longer
# attempt to mark nodes in zero expression regions.
G.node[node_id_map[n]][direction] = True
def _add_to_interval_trees(self, t):
istart = Interval(t.start, t.start + 1, value=t)
iend = Interval(t.end - 1, t.end, value=t)
self.tree_starts.insert_interval(istart)
self.tree_ends.insert_interval(iend)
def _trim_change_point(self, cp):
# search for matches in change point interval
num_trimmed = 0
if cp.sign < 0:
hits = self.tree_ends.find(cp.pos, cp.end)
for hit in hits:
t = hit.value
# last exon start cannot overlap interval
last_exon_start = t.exons[-1][0]
if cp.pos <= last_exon_start <= cp.end:
continue
# trim end left
t.exons[-1] = Exon(last_exon_start, cp.pos)
num_trimmed += 1
else:
hits = self.tree_starts.find(cp.start, cp.pos)
for hit in hits:
t = hit.value
# first exon end cannot overlap interval
first_exon_end = t.exons[0][1]
if cp.start <= first_exon_end <= cp.pos:
continue
# trim start right
t.exons[0] = Exon(cp.pos, first_exon_end)
num_trimmed += 1
def detect_change_points(self, *args, **kwargs):
'''
*args, **kwargs: passed directly to 'run_changepoint'
returns list of ChangePoint tuples
'''
changepts = []
for n_id in self.G:
n = self.get_node_interval(n_id)
expr_data = self.get_expr_data(n.start, n.end)
for cp in run_changepoint(expr_data, *args, **kwargs):
# add offset from start of node to change point positions
cp = cp._replace(pos=n.start + cp.pos,
start=n.start + cp.start,
end=n.start + cp.end)
changepts.append(cp)
logging.debug(
'\t%s:%d-%d[%s] node: %s-%s cp:%d(%d-%d) '
'p=%.3f fc=%.3f' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand), n.start, n.end, cp.pos,
cp.start, cp.end, cp.pvalue, cp.foldchange))
return changepts
def apply_change_point(self, cp, trim=True):
'''
trim: if true, will trim transfrags around change points
'''
if ((self.strand != Strand.NEG and cp.sign < 0)
or (self.strand == Strand.NEG and cp.sign > 0)):
self.stop_sites.add(cp.pos)
else:
self.start_sites.add(cp.pos)
if trim:
self._trim_change_point(cp)
def get_change_point_gtf(self, cp):
graph_id = (
'G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end, Strand.to_gtf(self.strand)))
features = []
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changept'
f.start = cp.pos
f.end = cp.pos + 1
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {
'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)
}
features.append(f)
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changeinterval'
f.start = cp.start
f.end = cp.end
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {
'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)
}
features.append(f)
return features
def split(self):
'''splits into weakly connected component subgraphs'''
# get connected components of graph which represent independent genes
# unconnected components are considered different genes
Gsubs = list(nx.weakly_connected_component_subgraphs(self.G))
if len(Gsubs) == 1:
yield self
return
# map nodes to components
node_subgraph_map = {}
subgraph_transfrag_map = collections.defaultdict(list)
for i, Gsub in enumerate(Gsubs):
for n_id in Gsub:
n = self.get_node_interval(n_id)
node_subgraph_map[n] = i
# assign transfrags to components
for t in self.itertransfrags():
for n in split_transfrag(t, self.node_bounds):
subgraph_id = node_subgraph_map[n]
subgraph_transfrag_map[subgraph_id].append(t)
break
# create new graphs using the separate components
for subgraph_transfrags in subgraph_transfrag_map.itervalues():
yield SpliceGraph.create(subgraph_transfrags,
guided_ends=self.guided_ends,
guided_assembly=self.guided_assembly)
def get_node_interval(self, n_id):
return self.G.node[n_id][SGNode.INTERVAL]
def get_node_id(self, n):
return self.G.graph['node_id_map'][n]
def get_node_expr_data(self, n_id):
start, end = self.get_node_interval(n_id)
return self.get_expr_data(start, end)
def itertransfrags(self):
if self.guided_assembly:
return chain(self.transfrags, self.ref_transfrags)
else:
return iter(self.transfrags)
def get_start_stop_nodes(self):
start_nodes = set()
stop_nodes = set()
for n, nd in self.G.nodes_iter(data=True):
if nd[SGNode.IS_START]:
start_nodes.add(n)
if nd[SGNode.IS_STOP]:
stop_nodes.add(n)
return start_nodes, stop_nodes
def get_expr_data(self, start=None, end=None):
if start is None:
start = self.start
if end is None:
end = self.end
if ((start < self.start) or (end > self.end)):
m = ('query %d-%d outside locus bounds %d-%d' %
(start, end, self.start, self.end))
raise TacoError(m)
astart = start - self.start
aend = end - self.start
return self.expr_data[astart:aend]
def get_node_gtf(self):
graph_id = (
'G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end, Strand.to_gtf(self.strand)))
# iterate through locus and return change point data
for n_id in self.G:
n = self.get_node_interval(n_id)
expr_data = self.get_expr_data(*n)
ref_starts = _array_subset(self.ref_start_sites, *n)
ref_stops = _array_subset(self.ref_stop_sites, *n)
# return gtf feature for each node
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'node'
f.start = n[0]
f.end = n[1]
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {
'graph_id': graph_id,
'expr_min': str(expr_data.min()),
'expr_max': str(expr_data.max()),
'expr_mean': str(expr_data.mean()),
'ref_starts': ','.join(map(str, ref_starts)),
'ref_stops': ','.join(map(str, ref_stops))
}
yield f
class SpliceGraph(object):
def __init__(self):
self.guided_ends = False
self.guided_assembly = False
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.start_sites = set()
self.stop_sites = set()
self.expr_data = None
self.node_bounds = None
self.G = None
def __str__(self):
return ('SpliceGraph %s:%d-%d[%s] transfrags: %d' %
(self.chrom, self.start, self.end, Strand.to_gtf(
self.strand), len(self.transfrags)))
@staticmethod
def create(transfrags, guided_ends=False, guided_assembly=False):
self = SpliceGraph()
self.guided_ends = guided_ends
self.guided_assembly = guided_assembly
self._add_transfrags(transfrags)
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
return self
def recreate(self):
self._add_transfrags(chain(self.transfrags, self.ref_transfrags))
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
def _add_transfrags(self, transfrags):
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
for t in transfrags:
if self.chrom is None:
self.chrom = t.chrom
elif self.chrom != t.chrom:
raise TacoError('chrom mismatch')
if self.strand is None:
self.strand = t.strand
elif self.strand != t.strand:
raise TacoError('strand mismatch')
if self.start is None:
self.start = t.start
else:
self.start = min(t.start, self.start)
if self.end is None:
self.end = t.end
else:
self.end = max(t.end, self.end)
if t.is_ref:
self.ref_start_sites.add(t.txstart)
self.ref_stop_sites.add(t.txstop)
self.ref_transfrags.append(t)
else:
self._add_to_interval_trees(t)
self.transfrags.append(t)
self.ref_start_sites = sorted(self.ref_start_sites)
self.ref_stop_sites = sorted(self.ref_stop_sites)
def _compute_expression(self):
expr_data = np.zeros(self.end - self.start, dtype=FLOAT_DTYPE)
for t in self.transfrags:
for exon in t.exons:
astart = exon.start - self.start
aend = exon.end - self.start
expr_data[astart:aend] += t.expr
return expr_data
def _find_node_boundaries(self):
node_bounds = set((self.start, self.end))
node_bounds.update(self.start_sites)
node_bounds.update(self.stop_sites)
# nodes bounded by regions where expression changes to/from zero
node_bounds.update(find_threshold_points(self.expr_data, self.start))
# nodes bounded by introns
for t in self.transfrags:
node_bounds.update(t.itersplices())
if self.guided_ends or self.guided_assembly:
for t in self.ref_transfrags:
if self.guided_ends:
node_bounds.update((t.start, t.end))
if self.guided_assembly:
node_bounds.update(t.itersplices())
return array('i', sorted(node_bounds))
def get_path(self, t):
node_id_map = self.G.node_id_map
nodes = [node_id_map[n] for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
return tuple(nodes)
def _create_splice_graph(self):
G = SGraph()
for t in self.itertransfrags():
nodes = [Exon(*n) for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
G.add_path(nodes, t.is_ref)
# after graph is built, set node properties for start and stop nodes
G.set_start_stop_nodes()
return G
def _mark_start_stop_nodes(self):
G = self.G
node_bounds = self.node_bounds
strand = self.strand
# mark start nodes
changepts = set(self.start_sites)
if self.guided_ends:
changepts.update(self.ref_start_sites)
for pos in changepts:
if strand != Strand.NEG:
bisect_func = bisect.bisect_right
else:
bisect_func = bisect.bisect_left
i = bisect_func(node_bounds, pos)
n = (node_bounds[i - 1], node_bounds[i])
if G.has_node(n):
n_id = G.get_node_id(n)
G.is_start[n_id] = True
# mark stop nodes
changepts = set(self.stop_sites)
if self.guided_ends:
changepts.update(self.ref_stop_sites)
for pos in changepts:
if strand == Strand.NEG:
bisect_func = bisect.bisect_right
else:
bisect_func = bisect.bisect_left
i = bisect_func(node_bounds, pos)
n = (node_bounds[i - 1], node_bounds[i])
if G.has_node(n):
n_id = G.get_node_id(n)
G.is_stop[n_id] = True
def _add_to_interval_trees(self, t):
istart = Interval(t.start, t.start + 1, value=t)
iend = Interval(t.end - 1, t.end, value=t)
self.tree_starts.insert_interval(istart)
self.tree_ends.insert_interval(iend)
def _trim_change_point(self, cp):
# search for matches in change point interval
num_trimmed = 0
if cp.sign < 0:
hits = self.tree_ends.find(cp.pos, cp.end)
for hit in hits:
t = hit.value
# last exon start cannot overlap interval
last_exon_start = t.exons[-1][0]
if cp.pos <= last_exon_start <= cp.end:
continue
# trim end left
t.exons[-1] = Exon(last_exon_start, cp.pos)
num_trimmed += 1
else:
hits = self.tree_starts.find(cp.start, cp.pos)
for hit in hits:
t = hit.value
# first exon end cannot overlap interval
first_exon_end = t.exons[0][1]
if cp.start <= first_exon_end <= cp.pos:
continue
# trim start right
t.exons[0] = Exon(cp.pos, first_exon_end)
num_trimmed += 1
def detect_change_points(self, *args, **kwargs):
'''
*args, **kwargs: passed directly to 'run_changepoint'
returns list of ChangePoint tuples
'''
changepts = []
for n in self.G.nodes_iter():
expr_data = self.get_expr_data(*n)
for cp in run_changepoint(expr_data, *args, **kwargs):
# add offset from start of node to change point positions
cp = cp._replace(pos=n.start + cp.pos,
start=n.start + cp.start,
end=n.start + cp.end)
changepts.append(cp)
logging.debug('%s changepoint node=(%s-%s) '
'pos=%d interval=(%d-%d) p=%.3f fc=%.3f' %
(str(self), n.start, n.end, cp.pos, cp.start,
cp.end, cp.pvalue, cp.foldchange))
return changepts
def apply_change_point(self, cp, trim=True):
'''
trim: if true, will trim transfrags around change points
'''
if ((self.strand != Strand.NEG and cp.sign < 0)
or (self.strand == Strand.NEG and cp.sign > 0)):
self.stop_sites.add(cp.pos)
else:
self.start_sites.add(cp.pos)
if trim:
self._trim_change_point(cp)
def get_change_point_gtf(self, cp):
graph_id = (
'G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end, Strand.to_gtf(self.strand)))
features = []
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changept'
f.start = cp.pos
f.end = cp.pos + 1
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {
'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)
}
features.append(f)
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changeinterval'
f.start = cp.start
f.end = cp.end
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {
'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)
}
features.append(f)
return features
def split(self):
'''splits into weakly connected component subgraphs'''
# get connected components of graph which represent independent genes
# unconnected components are considered different genes
num_components, components = self.G.weakly_connected_components()
if num_components == 1:
yield self
return
# map transfrags to components
component_transfrag_map = collections.defaultdict(list)
# assign transfrags to components
for t in self.itertransfrags():
for n in split_transfrag(t, self.node_bounds):
component_id = components[self.G.get_node_id(n)]
component_transfrag_map[component_id].append(t)
break
# create new graphs using the separate components
for component_transfrags in component_transfrag_map.itervalues():
yield SpliceGraph.create(component_transfrags,
guided_ends=self.guided_ends,
guided_assembly=self.guided_assembly)
def get_node_interval(self, n_id):
return self.G.get_node(n_id)
def get_node_id(self, n):
return self.G.get_node_id(n)
def get_node_expr_data(self, n_id):
start, end = self.G.get_node(n_id)
return self.get_expr_data(start, end)
def itertransfrags(self):
if self.guided_assembly:
return chain(self.transfrags, self.ref_transfrags)
else:
return iter(self.transfrags)
def get_start_stop_nodes(self):
start_nodes = set()
stop_nodes = set()
for i in self.G.node_ids_iter():
if self.G.is_start[i]:
start_nodes.add(i)
if self.G.is_stop[i]:
stop_nodes.add(i)
return start_nodes, stop_nodes
def reconstruct_exons(self, path):
# reverse negative stranded data so that all paths go from
# small -> large genomic coords
if self.strand == Strand.NEG:
path.reverse()
# convert from integer node labels to genome (start, end) tuples
path = [self.get_node_interval(nid) for nid in path]
# collapse contiguous nodes along path
newpath = []
chain = [path[0]]
for v in path[1:]:
if chain[-1].end != v.start:
# update path with merge chain node
newpath.append(Exon(chain[0].start, chain[-1].end))
# reset chain
chain = []
chain.append(v)
# add last chain
newpath.append(Exon(chain[0].start, chain[-1].end))
return newpath
def get_expr_data(self, start=None, end=None):
if start is None:
start = self.start
if end is None:
end = self.end
if ((start < self.start) or (end > self.end)):
m = ('query %d-%d outside locus bounds %d-%d' %
(start, end, self.start, self.end))
raise TacoError(m)
astart = start - self.start
aend = end - self.start
return self.expr_data[astart:aend]
def get_node_gtf(self):
graph_id = (
'G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end, Strand.to_gtf(self.strand)))
# iterate through locus and return change point data
for n_id in self.G.node_ids_iter():
n = self.get_node_interval(n_id)
expr_data = self.get_expr_data(*n)
ref_starts = _array_subset(self.ref_start_sites, *n)
ref_stops = _array_subset(self.ref_stop_sites, *n)
# return gtf feature for each node
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'node'
f.start = n[0]
f.end = n[1]
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {
'graph_id': graph_id,
'expr_min': str(expr_data.min()),
'expr_max': str(expr_data.max()),
'expr_mean': str(expr_data.mean()),
'ref_starts': ','.join(map(str, ref_starts)),
'ref_stops': ','.join(map(str, ref_stops))
}
yield f
class SpliceGraph(object):
def __init__(self):
self.guided_ends = False
self.guided_assembly = False
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.start_sites = set()
self.stop_sites = set()
self.expr_data = None
self.node_bounds = None
self.G = None
def __str__(self):
return ('SpliceGraph %s:%d-%d[%s] transfrags: %d' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand), len(self.transfrags)))
@staticmethod
def create(transfrags,
guided_ends=False,
guided_assembly=False):
self = SpliceGraph()
self.guided_ends = guided_ends
self.guided_assembly = guided_assembly
self._add_transfrags(transfrags)
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
return self
def recreate(self):
self._add_transfrags(chain(self.transfrags, self.ref_transfrags))
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
def _add_transfrags(self, transfrags):
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
for t in transfrags:
if self.chrom is None:
self.chrom = t.chrom
elif self.chrom != t.chrom:
raise TacoError('chrom mismatch')
if self.strand is None:
self.strand = t.strand
elif self.strand != t.strand:
raise TacoError('strand mismatch')
if self.start is None:
self.start = t.start
else:
self.start = min(t.start, self.start)
if self.end is None:
self.end = t.end
else:
self.end = max(t.end, self.end)
if t.is_ref:
self.ref_start_sites.add(t.txstart)
self.ref_stop_sites.add(t.txstop)
self.ref_transfrags.append(t)
else:
self._add_to_interval_trees(t)
self.transfrags.append(t)
self.ref_start_sites = sorted(self.ref_start_sites)
self.ref_stop_sites = sorted(self.ref_stop_sites)
def _compute_expression(self):
expr_data = np.zeros(self.end - self.start, dtype=FLOAT_DTYPE)
for t in self.transfrags:
for exon in t.exons:
astart = exon.start - self.start
aend = exon.end - self.start
expr_data[astart:aend] += t.expr
return expr_data
def _find_node_boundaries(self):
node_bounds = set((self.start, self.end))
node_bounds.update(self.start_sites)
node_bounds.update(self.stop_sites)
# nodes bounded by regions where expression changes to/from zero
node_bounds.update(find_threshold_points(self.expr_data, self.start))
# nodes bounded by introns
for t in self.transfrags:
node_bounds.update(t.itersplices())
if self.guided_ends or self.guided_assembly:
for t in self.ref_transfrags:
if self.guided_ends:
node_bounds.update((t.start, t.end))
if self.guided_assembly:
node_bounds.update(t.itersplices())
return array('i', sorted(node_bounds))
def get_path(self, t):
node_id_map = self.G.node_id_map
nodes = [node_id_map[n] for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
return tuple(nodes)
def _create_splice_graph(self):
G = SGraph()
for t in self.itertransfrags():
nodes = [Exon(*n) for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
G.add_path(nodes, t.is_ref)
# after graph is built, set node properties for start and stop nodes
G.set_start_stop_nodes()
return G
def _mark_start_stop_nodes(self):
G = self.G
node_bounds = self.node_bounds
strand = self.strand
# mark start nodes
changepts = set(self.start_sites)
if self.guided_ends:
changepts.update(self.ref_start_sites)
for pos in changepts:
if strand != Strand.NEG:
bisect_func = bisect.bisect_right
else:
bisect_func = bisect.bisect_left
i = bisect_func(node_bounds, pos)
n = (node_bounds[i-1], node_bounds[i])
if G.has_node(n):
n_id = G.get_node_id(n)
G.is_start[n_id] = True
# mark stop nodes
changepts = set(self.stop_sites)
if self.guided_ends:
changepts.update(self.ref_stop_sites)
for pos in changepts:
if strand == Strand.NEG:
bisect_func = bisect.bisect_right
else:
bisect_func = bisect.bisect_left
i = bisect_func(node_bounds, pos)
n = (node_bounds[i-1], node_bounds[i])
if G.has_node(n):
n_id = G.get_node_id(n)
G.is_stop[n_id] = True
def _add_to_interval_trees(self, t):
istart = Interval(t.start, t.start+1, value=t)
iend = Interval(t.end-1, t.end, value=t)
self.tree_starts.insert_interval(istart)
self.tree_ends.insert_interval(iend)
def _trim_change_point(self, cp):
# search for matches in change point interval
num_trimmed = 0
if cp.sign < 0:
hits = self.tree_ends.find(cp.pos, cp.end)
for hit in hits:
t = hit.value
# last exon start cannot overlap interval
last_exon_start = t.exons[-1][0]
if cp.pos <= last_exon_start <= cp.end:
continue
# trim end left
t.exons[-1] = Exon(last_exon_start, cp.pos)
num_trimmed += 1
else:
hits = self.tree_starts.find(cp.start, cp.pos)
for hit in hits:
t = hit.value
# first exon end cannot overlap interval
first_exon_end = t.exons[0][1]
if cp.start <= first_exon_end <= cp.pos:
continue
# trim start right
t.exons[0] = Exon(cp.pos, first_exon_end)
num_trimmed += 1
def detect_change_points(self, *args, **kwargs):
'''
*args, **kwargs: passed directly to 'run_changepoint'
returns list of ChangePoint tuples
'''
changepts = []
for n in self.G.nodes_iter():
expr_data = self.get_expr_data(*n)
for cp in run_changepoint(expr_data, *args, **kwargs):
# add offset from start of node to change point positions
cp = cp._replace(pos=n.start + cp.pos,
start=n.start + cp.start,
end=n.start + cp.end)
changepts.append(cp)
logging.debug('%s changepoint node=(%s-%s) '
'pos=%d interval=(%d-%d) p=%.3f fc=%.3f' %
(str(self), n.start,
n.end, cp.pos, cp.start, cp.end,
cp.pvalue, cp.foldchange))
return changepts
def apply_change_point(self, cp, trim=True):
'''
trim: if true, will trim transfrags around change points
'''
if ((self.strand != Strand.NEG and cp.sign < 0) or
(self.strand == Strand.NEG and cp.sign > 0)):
self.stop_sites.add(cp.pos)
else:
self.start_sites.add(cp.pos)
if trim:
self._trim_change_point(cp)
def get_change_point_gtf(self, cp):
graph_id = ('G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand)))
features = []
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changept'
f.start = cp.pos
f.end = cp.pos + 1
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)}
features.append(f)
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changeinterval'
f.start = cp.start
f.end = cp.end
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)}
features.append(f)
return features
def split(self):
'''splits into weakly connected component subgraphs'''
# get connected components of graph which represent independent genes
# unconnected components are considered different genes
num_components, components = self.G.weakly_connected_components()
if num_components == 1:
yield self
return
# map transfrags to components
component_transfrag_map = collections.defaultdict(list)
# assign transfrags to components
for t in self.itertransfrags():
for n in split_transfrag(t, self.node_bounds):
component_id = components[self.G.get_node_id(n)]
component_transfrag_map[component_id].append(t)
break
# create new graphs using the separate components
for component_transfrags in component_transfrag_map.itervalues():
yield SpliceGraph.create(component_transfrags,
guided_ends=self.guided_ends,
guided_assembly=self.guided_assembly)
def get_node_interval(self, n_id):
return self.G.get_node(n_id)
def get_node_id(self, n):
return self.G.get_node_id(n)
def get_node_expr_data(self, n_id):
start, end = self.G.get_node(n_id)
return self.get_expr_data(start, end)
def itertransfrags(self):
if self.guided_assembly:
return chain(self.transfrags, self.ref_transfrags)
else:
return iter(self.transfrags)
def get_start_stop_nodes(self):
start_nodes = set()
stop_nodes = set()
for i in self.G.node_ids_iter():
if self.G.is_start[i]:
start_nodes.add(i)
if self.G.is_stop[i]:
stop_nodes.add(i)
return start_nodes, stop_nodes
def reconstruct_exons(self, path):
# reverse negative stranded data so that all paths go from
# small -> large genomic coords
if self.strand == Strand.NEG:
path.reverse()
# convert from integer node labels to genome (start, end) tuples
path = [self.get_node_interval(nid) for nid in path]
# collapse contiguous nodes along path
newpath = []
chain = [path[0]]
for v in path[1:]:
if chain[-1].end != v.start:
# update path with merge chain node
newpath.append(Exon(chain[0].start,
chain[-1].end))
# reset chain
chain = []
chain.append(v)
# add last chain
newpath.append(Exon(chain[0].start, chain[-1].end))
return newpath
def get_expr_data(self, start=None, end=None):
if start is None:
start = self.start
if end is None:
end = self.end
if ((start < self.start) or (end > self.end)):
m = ('query %d-%d outside locus bounds %d-%d' %
(start, end, self.start, self.end))
raise TacoError(m)
astart = start - self.start
aend = end - self.start
return self.expr_data[astart:aend]
def get_node_gtf(self):
graph_id = ('G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand)))
# iterate through locus and return change point data
for n_id in self.G.node_ids_iter():
n = self.get_node_interval(n_id)
expr_data = self.get_expr_data(*n)
ref_starts = _array_subset(self.ref_start_sites, *n)
ref_stops = _array_subset(self.ref_stop_sites, *n)
# return gtf feature for each node
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'node'
f.start = n[0]
f.end = n[1]
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {'graph_id': graph_id,
'expr_min': str(expr_data.min()),
'expr_max': str(expr_data.max()),
'expr_mean': str(expr_data.mean()),
'ref_starts': ','.join(map(str, ref_starts)),
'ref_stops': ','.join(map(str, ref_stops))}
yield f
class SpliceGraph(object):
def __init__(self):
self.guided_ends = False
self.guided_assembly = False
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.start_sites = set()
self.stop_sites = set()
self.expr_data = None
self.node_bounds = None
self.G = None
@staticmethod
def create(transfrags,
guided_ends=False,
guided_assembly=False):
self = SpliceGraph()
self.guided_ends = guided_ends
self.guided_assembly = guided_assembly
self._add_transfrags(transfrags)
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
return self
def recreate(self):
self._add_transfrags(chain(self.transfrags, self.ref_transfrags))
self.expr_data = self._compute_expression()
self.node_bounds = self._find_node_boundaries()
self.G = self._create_splice_graph()
self._mark_start_stop_nodes()
def _add_transfrags(self, transfrags):
self.transfrags = []
self.ref_transfrags = []
self.chrom = None
self.start = None
self.end = None
self.strand = None
self.ref_start_sites = set()
self.ref_stop_sites = set()
self.tree_starts = IntervalTree()
self.tree_ends = IntervalTree()
for t in transfrags:
if self.chrom is None:
self.chrom = t.chrom
elif self.chrom != t.chrom:
raise TacoError('chrom mismatch')
if self.strand is None:
self.strand = t.strand
elif self.strand != t.strand:
raise TacoError('strand mismatch')
if self.start is None:
self.start = t.start
else:
self.start = min(t.start, self.start)
if self.end is None:
self.end = t.end
else:
self.end = max(t.end, self.end)
if t.is_ref:
self.ref_start_sites.add(t.txstart)
self.ref_stop_sites.add(t.txstop)
self.ref_transfrags.append(t)
else:
self._add_to_interval_trees(t)
self.transfrags.append(t)
self.ref_start_sites = sorted(self.ref_start_sites)
self.ref_stop_sites = sorted(self.ref_stop_sites)
def _compute_expression(self):
expr_data = np.zeros(self.end - self.start, dtype=FLOAT_DTYPE)
for t in self.transfrags:
for exon in t.exons:
astart = exon.start - self.start
aend = exon.end - self.start
expr_data[astart:aend] += t.expr
return expr_data
def _find_node_boundaries(self):
node_bounds = set((self.start, self.end))
node_bounds.update(self.start_sites)
node_bounds.update(self.stop_sites)
# nodes bounded by regions where expression changes to/from zero
node_bounds.update(find_threshold_points(self.expr_data, self.start))
# nodes bounded by introns
for t in self.transfrags:
node_bounds.update(t.itersplices())
if self.guided_ends or self.guided_assembly:
for t in self.ref_transfrags:
if self.guided_ends:
node_bounds.update((t.start, t.end))
if self.guided_assembly:
node_bounds.update(t.itersplices())
return array('i', sorted(node_bounds))
def get_path(self, t):
node_id_map = self.G.graph['node_id_map']
nodes = [node_id_map[n] for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
return tuple(nodes)
def _create_splice_graph2(self):
G = SGraph()
for t in sgraph.itertransfrags():
nodes = [n for n in split_transfrag(t, self.node_bounds)]
if self.strand == Strand.NEG:
nodes.reverse()
G.add_path(nodes, t.is_ref)
return G
def _create_splice_graph(self):
'''returns networkx DiGraph object'''
G = nx.DiGraph()
node_bounds = self.node_bounds
node_id_map = {}
id_node_map = {}
current_id = 2
for t in self.itertransfrags():
# split exons that cross boundaries and get the
# nodes that made up the transfrag
nodes = []
for n in split_transfrag(t, node_bounds):
n = Exon(*n)
if n not in node_id_map:
n_id = current_id
current_id += 1
node_id_map[n] = n_id
id_node_map[n_id] = n
else:
n_id = node_id_map[n]
nodes.append(n_id)
if t.strand == Strand.NEG:
nodes.reverse()
# add nodes/edges to graph
u = nodes[0]
SGNode.add(G, u, id_node_map[u], is_ref=t.is_ref)
for i in xrange(1, len(nodes)):
v = nodes[i]
SGNode.add(G, v, id_node_map[v], is_ref=t.is_ref)
G.add_edge(u, v)
u = v
G.graph['node_id_map'] = node_id_map
G.graph['id_node_map'] = id_node_map
return G
def _mark_start_stop_nodes(self):
G = self.G
# get all leaf nodes
for n, nd in G.nodes_iter(data=True):
if G.in_degree(n) == 0:
nd[SGNode.IS_START] = True
if G.out_degree(n) == 0:
nd[SGNode.IS_STOP] = True
# mark change points
change_points = set()
change_points.update(set((SGNode.IS_START, x) for x in self.start_sites))
change_points.update(set((SGNode.IS_STOP, x) for x in self.stop_sites))
if self.guided_ends:
change_points.update((SGNode.IS_START, x)
for x in self.ref_start_sites)
change_points.update((SGNode.IS_STOP, x)
for x in self.ref_stop_sites)
node_bounds = self.node_bounds
strand = self.strand
node_id_map = G.graph['node_id_map']
for direction, pos in change_points:
if ((direction == SGNode.IS_STOP and strand == Strand.NEG) or
(direction == SGNode.IS_START and strand != Strand.NEG)):
bisect_func = bisect.bisect_right
else:
bisect_func = bisect.bisect_left
i = bisect_func(node_bounds, pos)
n = (node_bounds[i-1], node_bounds[i])
if n in node_id_map:
# 2/5/2016: observed case where trimming caused an interval
# with zero expression, and this function then crashed when
# attempting to mark the node as a start/stop. We no longer
# attempt to mark nodes in zero expression regions.
G.node[node_id_map[n]][direction] = True
def _add_to_interval_trees(self, t):
istart = Interval(t.start, t.start+1, value=t)
iend = Interval(t.end-1, t.end, value=t)
self.tree_starts.insert_interval(istart)
self.tree_ends.insert_interval(iend)
def _trim_change_point(self, cp):
# search for matches in change point interval
num_trimmed = 0
if cp.sign < 0:
hits = self.tree_ends.find(cp.pos, cp.end)
for hit in hits:
t = hit.value
# last exon start cannot overlap interval
last_exon_start = t.exons[-1][0]
if cp.pos <= last_exon_start <= cp.end:
continue
# trim end left
t.exons[-1] = Exon(last_exon_start, cp.pos)
num_trimmed += 1
else:
hits = self.tree_starts.find(cp.start, cp.pos)
for hit in hits:
t = hit.value
# first exon end cannot overlap interval
first_exon_end = t.exons[0][1]
if cp.start <= first_exon_end <= cp.pos:
continue
# trim start right
t.exons[0] = Exon(cp.pos, first_exon_end)
num_trimmed += 1
def detect_change_points(self, *args, **kwargs):
'''
*args, **kwargs: passed directly to 'run_changepoint'
returns list of ChangePoint tuples
'''
changepts = []
for n_id in self.G:
n = self.get_node_interval(n_id)
expr_data = self.get_expr_data(n.start, n.end)
for cp in run_changepoint(expr_data, *args, **kwargs):
# add offset from start of node to change point positions
cp = cp._replace(pos=n.start + cp.pos,
start=n.start + cp.start,
end=n.start + cp.end)
changepts.append(cp)
logging.debug('\t%s:%d-%d[%s] node: %s-%s cp:%d(%d-%d) '
'p=%.3f fc=%.3f' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand), n.start,
n.end, cp.pos, cp.start, cp.end,
cp.pvalue, cp.foldchange))
return changepts
def apply_change_point(self, cp, trim=True):
'''
trim: if true, will trim transfrags around change points
'''
if ((self.strand != Strand.NEG and cp.sign < 0) or
(self.strand == Strand.NEG and cp.sign > 0)):
self.stop_sites.add(cp.pos)
else:
self.start_sites.add(cp.pos)
if trim:
self._trim_change_point(cp)
def get_change_point_gtf(self, cp):
graph_id = ('G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand)))
features = []
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changept'
f.start = cp.pos
f.end = cp.pos + 1
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)}
features.append(f)
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'changeinterval'
f.start = cp.start
f.end = cp.end
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {'graph_id': graph_id,
'sign': str(cp.sign),
'pvalue': str(cp.pvalue),
'foldchange': str(cp.foldchange)}
features.append(f)
return features
def split(self):
'''splits into weakly connected component subgraphs'''
# get connected components of graph which represent independent genes
# unconnected components are considered different genes
Gsubs = list(nx.weakly_connected_component_subgraphs(self.G))
if len(Gsubs) == 1:
yield self
return
# map nodes to components
node_subgraph_map = {}
subgraph_transfrag_map = collections.defaultdict(list)
for i, Gsub in enumerate(Gsubs):
for n_id in Gsub:
n = self.get_node_interval(n_id)
node_subgraph_map[n] = i
# assign transfrags to components
for t in self.itertransfrags():
for n in split_transfrag(t, self.node_bounds):
subgraph_id = node_subgraph_map[n]
subgraph_transfrag_map[subgraph_id].append(t)
break
# create new graphs using the separate components
for subgraph_transfrags in subgraph_transfrag_map.itervalues():
yield SpliceGraph.create(subgraph_transfrags,
guided_ends=self.guided_ends,
guided_assembly=self.guided_assembly)
def get_node_interval(self, n_id):
return self.G.node[n_id][SGNode.INTERVAL]
def get_node_id(self, n):
return self.G.graph['node_id_map'][n]
def get_node_expr_data(self, n_id):
start, end = self.get_node_interval(n_id)
return self.get_expr_data(start, end)
def itertransfrags(self):
if self.guided_assembly:
return chain(self.transfrags, self.ref_transfrags)
else:
return iter(self.transfrags)
def get_start_stop_nodes(self):
start_nodes = set()
stop_nodes = set()
for n, nd in self.G.nodes_iter(data=True):
if nd[SGNode.IS_START]:
start_nodes.add(n)
if nd[SGNode.IS_STOP]:
stop_nodes.add(n)
return start_nodes, stop_nodes
def get_expr_data(self, start=None, end=None):
if start is None:
start = self.start
if end is None:
end = self.end
if ((start < self.start) or (end > self.end)):
m = ('query %d-%d outside locus bounds %d-%d' %
(start, end, self.start, self.end))
raise TacoError(m)
astart = start - self.start
aend = end - self.start
return self.expr_data[astart:aend]
def get_node_gtf(self):
graph_id = ('G_%s_%d_%d_%s' %
(self.chrom, self.start, self.end,
Strand.to_gtf(self.strand)))
# iterate through locus and return change point data
for n_id in self.G:
n = self.get_node_interval(n_id)
expr_data = self.get_expr_data(*n)
ref_starts = _array_subset(self.ref_start_sites, *n)
ref_stops = _array_subset(self.ref_stop_sites, *n)
# return gtf feature for each node
f = GTF.Feature()
f.seqid = self.chrom
f.source = 'taco'
f.feature = 'node'
f.start = n[0]
f.end = n[1]
f.score = 0
f.strand = Strand.to_gtf(self.strand)
f.phase = '.'
f.attrs = {'graph_id': graph_id,
'expr_min': str(expr_data.min()),
'expr_max': str(expr_data.max()),
'expr_mean': str(expr_data.mean()),
'ref_starts': ','.join(map(str, ref_starts)),
'ref_stops': ','.join(map(str, ref_stops))}
yield f