if included_subreddits is None:
included_subreddits = select_topN_subreddits(topN)
else:
- included_subreddits = set(open(included_subreddits))
+ included_subreddits = set(map(str.strip,map(str.lower,open(included_subreddits))))
- if exclude_phrases == True:
- tfidf = tfidf.filter(~f.col(term_colname).contains("_"))
+ ds_filter = ds.field("subreddit").isin(included_subreddits)
+
+ if min_df is not None:
+ ds_filter &= ds.field("count") >= min_df
+
+ if max_df is not None:
+ ds_filter &= ds.field("count") <= max_df
+
+ if week is not None:
+ ds_filter &= ds.field("week") == week
+
+ if from_date is not None:
+ ds_filter &= ds.field("week") >= from_date
- print("creating temporary parquet with matrix indicies")
- tempdir = prep_tfidf_entries(tfidf, term_colname, min_df, max_df, included_subreddits)
+ if to_date is not None:
+ ds_filter &= ds.field("week") <= to_date
- tfidf = spark.read.parquet(tempdir.name)
- subreddit_names = tfidf.select(['subreddit','subreddit_id_new']).distinct().toPandas()
+ term = term_colname
+ term_id = term + '_id'
+ term_id_new = term + '_id_new'
+
+ projection = {
+ 'subreddit_id':ds.field('subreddit_id'),
+ term_id:ds.field(term_id),
+ 'relative_tf':ds.field("relative_tf").cast('float32')
+ }
+
+ if not rescale_idf:
+ projection = {
+ 'subreddit_id':ds.field('subreddit_id'),
+ term_id:ds.field(term_id),
+ 'relative_tf':ds.field('relative_tf').cast('float32'),
+ 'tf_idf':ds.field('tf_idf').cast('float32')}
+
+ tfidf_ds = ds.dataset(infile)
+
+ df = tfidf_ds.to_table(filter=ds_filter,columns=projection)
+
+ df = df.to_pandas(split_blocks=True,self_destruct=True)
+ print("assigning indexes",flush=True)
+ df['subreddit_id_new'] = df.groupby("subreddit_id").ngroup()
+ grouped = df.groupby(term_id)
+ df[term_id_new] = grouped.ngroup()
+
+ if rescale_idf:
+ print("computing idf", flush=True)
+ df['new_count'] = grouped[term_id].transform('count')
+ N_docs = df.subreddit_id_new.max() + 1
+ df['idf'] = np.log(N_docs/(1+df.new_count),dtype='float32') + 1
+ if tf_family == tf_weight.MaxTF:
+ df["tf_idf"] = df.relative_tf * df.idf
+ else: # tf_fam = tf_weight.Norm05
+ df["tf_idf"] = (0.5 + 0.5 * df.relative_tf) * df.idf
+
+ print("assigning names")
+ subreddit_names = tfidf_ds.to_table(filter=ds_filter,columns=['subreddit','subreddit_id'])
+ batches = subreddit_names.to_batches()
+
+ with Pool(cpu_count()) as pool:
+ chunks = pool.imap_unordered(pull_names,batches)
+ subreddit_names = pd.concat(chunks,copy=False).drop_duplicates()
+
+ subreddit_names = subreddit_names.set_index("subreddit_id")
+ new_ids = df.loc[:,['subreddit_id','subreddit_id_new']].drop_duplicates()
+ new_ids = new_ids.set_index('subreddit_id')
+ subreddit_names = subreddit_names.join(new_ids,on='subreddit_id').reset_index()
+ subreddit_names = subreddit_names.drop("subreddit_id",1)
subreddit_names = subreddit_names.sort_values("subreddit_id_new")
- subreddit_names['subreddit_id_new'] = subreddit_names['subreddit_id_new'] - 1
- spark.stop()
- return (tempdir, subreddit_names)
+ return(df, subreddit_names)
+def pull_names(batch):
+ return(batch.to_pandas().drop_duplicates())
-def similarities(infile, simfunc, term_colname, outfile, min_df=None, max_df=None, included_subreddits=None, topN=500, exclude_phrases=False, from_date=None, to_date=None, tfidf_colname='tf_idf'):
+def similarities(infile, simfunc, term_colname, outfile, min_df=None, max_df=None, included_subreddits=None, topN=500, from_date=None, to_date=None, tfidf_colname='tf_idf'):
'''
tfidf_colname: set to 'relative_tf' to use normalized term frequency instead of tf-idf, which can be useful for author-based similarities.
'''