refactor: separate statistic computation

Snakefile

@@ -2,11 +2,12 @@ import os
 from spras import runner
 import shutil
 import yaml
-from spras.dataset import Dataset
-from spras.evaluation import Evaluation
 from spras.analysis import ml, summary, cytoscape
 from spras.config.revision import detach_spras_revision
 import spras.config.config as _config
+from spras.dataset import Dataset
+from spras.evaluation import Evaluation
+from spras.statistics import from_output_pathway, statistics_computation, statistics_options
 
 # Snakemake updated the behavior in the 6.5.0 release https://github.com/snakemake/snakemake/pull/1037
 # and using the wrong separator prevents Snakemake from matching filenames to the rules that can produce them
@@ -312,18 +313,36 @@ rule viz_cytoscape:
     run:
         cytoscape.run_cytoscape(input.pathways, output.session, container_settings)
 
+# We generate new Snakemake rules for every statistic
+# to allow parallel and lazy computation of individual statistics
+for keys, values in statistics_computation.items():
+    pythonic_name = 'generate_' + '_and_'.join([key.lower().replace(' ', '_') for key in keys])
+    rule:
+        # (See https://snakemake.readthedocs.io/en/stable/snakefiles/rules.html#procedural-rule-definition)
+        name: pythonic_name
+        input: pathway_file = rules.parse_output.output.standardized_file
+        output: [SEP.join([out_dir, '{dataset}-{algorithm}-{params}', 'statistics', f'{key}.txt']) for key in keys]
+        run:
+            (Path(input.pathway_file).parent / 'statistics').mkdir(exist_ok=True)
+            graph = from_output_pathway(input.pathway_file)
+            for computed, output in zip(values(graph), output):
+                Path(output).write_text(str(computed))
 
 # Write a single summary table for all pathways for each dataset
 rule summary_table:
     input:
         # Collect all pathways generated for the dataset
         pathways = expand('{out_dir}{sep}{{dataset}}-{algorithm_params}{sep}pathway.txt', out_dir=out_dir, sep=SEP, algorithm_params=algorithms_with_params),
-        dataset_file = SEP.join([out_dir, 'dataset-{dataset}-merged.pickle'])
+        dataset_file = SEP.join([out_dir, 'dataset-{dataset}-merged.pickle']),
+        # Collect all possible options
+        statistics = expand(
+            '{out_dir}{sep}{{dataset}}-{algorithm_params}{sep}statistics{sep}{statistic}.txt',
+            out_dir=out_dir, sep=SEP, algorithm_params=algorithms_with_params, statistic=statistics_options)
     output: summary_table = SEP.join([out_dir, '{dataset}-pathway-summary.txt'])
     run:
         # Load the node table from the pickled dataset file
         node_table = Dataset.from_file(input.dataset_file).node_table
-        summary_df = summary.summarize_networks(input.pathways, node_table, algorithm_params, algorithms_with_params)
+        summary_df = summary.summarize_networks(input.pathways, node_table, algorithm_params, algorithms_with_params, input.statistics)
         summary_df.to_csv(output.summary_table, sep='\t', index=False)
 
 # Cluster the output pathways for each dataset

spras/analysis/summary.py

@@ -1,14 +1,15 @@
+import ast
 import json
 from pathlib import Path
-from statistics import median
 from typing import Iterable
 
-import networkx as nx
 import pandas as pd
 
+from spras.statistics import from_output_pathway
+
 
 def summarize_networks(file_paths: Iterable[Path], node_table: pd.DataFrame, algo_params: dict[str, dict],
-                       algo_with_params: list[str]) -> pd.DataFrame:
+                       algo_with_params: list[str], statistics_files: list) -> pd.DataFrame:
     """
     Generate a table that aggregates summary information about networks in file_paths, including which nodes are present
     in node_table columns. Network directionality is ignored and all edges are treated as undirected. The order of the
@@ -18,6 +19,7 @@ def summarize_networks(file_paths: Iterable[Path], node_table: pd.DataFrame, alg
     @param algo_params: a nested dict mapping algorithm names to dicts that map parameter hashes to parameter
     combinations.
     @param algo_with_params: a list of <algorithm>-params-<params_hash> combinations
+    @param statistics_files: a list of statistic files with the computed statistics.
     @return: pandas DataFrame with summary information
     """
     # Ensure that NODEID is the first column
@@ -40,52 +42,18 @@ def summarize_networks(file_paths: Iterable[Path], node_table: pd.DataFrame, alg
 
     # Iterate through each network file path
     for index, file_path in enumerate(sorted(file_paths)):
-        with open(file_path, 'r') as f:
-            lines = f.readlines()[1:]  # skip the header line
-
         # directed or mixed graphs are parsed and summarized as an undirected graph
-        nw = nx.read_edgelist(lines, data=(('weight', float), ('Direction', str)))
+        nw = from_output_pathway(file_path)
 
         # Save the network name, number of nodes, number edges, and number of connected components
         nw_name = str(file_path)
-        number_nodes = nw.number_of_nodes()
-        number_edges = nw.number_of_edges()
-        ncc = nx.number_connected_components(nw)
-
-        # Save the max/median degree, average clustering coefficient, and density
-        if number_nodes == 0:
-            max_degree = 0
-            median_degree = 0.0
-            density = 0.0
-        else:
-            degrees = [deg for _, deg in nw.degree()]
-            max_degree = max(degrees)
-            median_degree = median(degrees)
-            density = nx.density(nw)
-
-        cc = list(nx.connected_components(nw))
-        # Save the max diameter
-        # Use diameter only for components with ≥2 nodes (singleton components have diameter 0)
-        diameters = [
-            nx.diameter(nw.subgraph(c).copy()) if len(c) > 1 else 0
-            for c in cc
-        ]
-        max_diameter = max(diameters, default=0)
-
-        # Save the average path lengths
-        # Compute average shortest path length only for components with ≥2 nodes (undefined for singletons, set to 0.0)
-        avg_path_lengths = [
-            nx.average_shortest_path_length(nw.subgraph(c).copy()) if len(c) > 1 else 0.0
-            for c in cc
-        ]
-
-        if len(avg_path_lengths) != 0:
-            avg_path_len = sum(avg_path_lengths) / len(avg_path_lengths)
-        else:
-            avg_path_len = 0.0
+
+        # We use ast.literal_eval here to convert statistic file outputs to ints or floats depending on their string representation.
+        # (e.g. "5.0" -> float(5.0), while "5" -> int(5).)
+        graph_statistics = [ast.literal_eval(Path(file).read_text()) for file in statistics_files]
 
         # Initialize list to store current network information
-        cur_nw_info = [nw_name, number_nodes, number_edges, ncc, density, max_degree, median_degree, max_diameter, avg_path_len]
+        cur_nw_info = [nw_name, *graph_statistics]
 
         # Iterate through each node property and save the intersection with the current network
         for node_list in nodes_by_col:
@@ -107,8 +75,10 @@ def summarize_networks(file_paths: Iterable[Path], node_table: pd.DataFrame, alg
         # Save the current network information to the network summary list
         nw_info.append(cur_nw_info)
 
+    # Get the list of statistic names by their file names
+    statistics_options = [Path(file).stem for file in statistics_files]
     # Prepare column names
-    col_names = ['Name', 'Number of nodes', 'Number of edges', 'Number of connected components', 'Density', 'Max degree', 'Median degree', 'Max diameter', 'Average path length']
+    col_names = ['Name', *statistics_options]
     col_names.extend(nodes_by_col_labs)
     col_names.append('Parameter combination')
 
@@ -122,65 +92,4 @@ def summarize_networks(file_paths: Iterable[Path], node_table: pd.DataFrame, alg
     return nw_info
 
 
-def degree(g):
-    return dict(g.degree)
-
-# TODO: redo .run code to work on mixed graphs
-# stats is just a list of functions to apply to the graph.
-# They should take as input a networkx graph or digraph but may have any output.
-# stats = [degree, nx.clustering, nx.betweenness_centrality]
-
-
-# def produce_statistics(g: nx.Graph, s=None) -> dict:
-#     global stats
-#     if s is not None:
-#         stats = s
-#     d = dict()
-#     for s in stats:
-#         sname = s.__name__
-#         d[sname] = s(g)
-#     return d
-
-
-# def load_graph(path: str) -> nx.Graph:
-#     g = nx.read_edgelist(path, data=(('weight', float), ('Direction',str)))
-#     return g
-
-
-# def save(data, pth):
-#     fout = open(pth, 'w')
-#     fout.write('#node\t%s\n' % '\t'.join([s.__name__ for s in stats]))
-#     for node in data[stats[0].__name__]:
-#         row = [data[s.__name__][node] for s in stats]
-#         fout.write('%s\t%s\n' % (node, '\t'.join([str(d) for d in row])))
-#     fout.close()
-
-
-# def run(infile: str, outfile: str) -> None:
-#     """
-#     run function that wraps above functions.
-#     """
-#     # if output directory doesn't exist, make it.
-#     outdir = os.path.dirname(outfile)
-#     if not os.path.exists(outdir):
-#         os.makedirs(outdir)
-
-#     # load graph, produce stats, and write to human-readable file.
-#     g = load_graph(infile)
-#     dat = produce_statistics(g)
-#     save(dat, outfile)
-
-
-# def main(argv):
-#     """
-#     for testing
-#     """
-#     g = load_graph(argv[1])
-#     print(g.nodes)
-#     dat = produce_statistics(g)
-#     print(dat)
-#     save(dat, argv[2])
-
-
-# if __name__ == '__main__':
-#     main(sys.argv)
+# TODO: redo the above code to work on mixed graphs

spras/statistics.py

@@ -0,0 +1,76 @@
+"""
+Graph statistics, used to power summary.py.
+
+We allow for arbitrary computation of any specific statistic on some graph,
+computing more than necessary if we have dependencies. See the top level
+`statistics_computation` dictionary for usage.
+
+To make the statistics allow directed graph input, they will always take
+in a networkx.DiGraph, which contains even more information, even though
+the underlying graph may be just as easily represented by networkx.Graph.
+"""
+
+import itertools
+from statistics import median
+from typing import Callable
+
+import networkx as nx
+
+
+def compute_degree(graph: nx.DiGraph) -> tuple[int, float]:
+    """
+    Computes the (max, median) degree of a `graph`.
+    """
+    # number_of_nodes is a cheap call
+    if graph.number_of_nodes() == 0:
+        return (0, 0.0)
+    else:
+        degrees = [deg for _, deg in graph.degree()]
+        return max(degrees), median(degrees)
+
+def compute_on_cc(directed_graph: nx.DiGraph) -> tuple[int, float]:
+    # We convert our directed_graph to an undirected graph as networkx (reasonably) does
+    # not allow for computing the connected components of a directed graph, but the connected
+    # component count still is a useful statistic for us.
+    graph: nx.Graph = directed_graph.to_undirected()
+    cc = list(nx.connected_components(graph))
+    # Save the max diameter
+    # Use diameter only for components with ≥2 nodes (singleton components have diameter 0)
+    diameters = [
+        nx.diameter(graph.subgraph(c).copy()) if len(c) > 1 else 0
+        for c in cc
+    ]
+    max_diameter = max(diameters, default=0)
+
+    # Save the average path lengths
+    # Compute average shortest path length only for components with ≥2 nodes (undefined for singletons, set to 0.0)
+    avg_path_lengths = [
+        nx.average_shortest_path_length(graph.subgraph(c).copy()) if len(c) > 1 else 0.0
+        for c in cc
+    ]
+
+    if len(avg_path_lengths) != 0:
+        avg_path_len = sum(avg_path_lengths) / len(avg_path_lengths)
+    else:
+        avg_path_len = 0.0
+
+    return max_diameter, avg_path_len
+
+# The type signature here is meant to be 'an n-tuple has n-outputs.'
+statistics_computation: dict[tuple[str, ...], Callable[[nx.DiGraph], tuple[float | int, ...]]] = {
+    ('Number of nodes',): lambda graph : (graph.number_of_nodes(),),
+    ('Number of edges',): lambda graph : (graph.number_of_edges(),),
+    ('Number of connected components',): lambda graph : (nx.number_connected_components(graph.to_undirected()),),
+    ('Density',): lambda graph : (nx.density(graph),),
+    ('Max degree', 'Median degree'): compute_degree,
+    ('Max diameter', 'Average path length'): compute_on_cc,
+}
+
+# All of the keys inside statistics_computation, flattened.
+statistics_options: list[str] = list(itertools.chain(*(list(key) for key in statistics_computation.keys())))
+
+def from_output_pathway(lines) -> nx.Graph:
+    with open(lines, 'r') as f:
+        lines = f.readlines()[1:]
+
+    return nx.read_edgelist(lines, data=(('Rank', int), ('Direction', str)))