improve summary chunking (containers#397)

Signed-off-by: Michael Clifford <mcliffor@redhat.com>

recipes/natural_language_processing/summarizer/app/summarizer.py

@@ -3,6 +3,7 @@
 from langchain.prompts import PromptTemplate
 from langchain_community.callbacks import StreamlitCallbackHandler
 from langchain_community.document_loaders import PyMuPDFLoader
+from langchain_text_splitters import RecursiveCharacterTextSplitter
 from rouge_score import rouge_scorer
 import streamlit as st
 import tempfile
@@ -34,22 +35,32 @@ def checking_model_service():
 with st.spinner("Checking Model Service Availability..."):
     checking_model_service()
 
+def split_append_chunk(chunk, list):
+    chunk_length = len(chunk)
+    chunk1 = " ".join(chunk.split()[:chunk_length])
+    chunk2 = " ".join(chunk.split()[chunk_length:])
+    list.extend([chunk1, chunk2])
 
 def chunk_text(text):
     chunks = []
-    chunk_size = 1024
-    tokens = requests.post(f"{model_service[:-2]}extras/tokenize/",
-                  json={"input":text}).content
-    tokens = json.loads(tokens)["tokens"]
-    num_tokens = len(tokens)
-    num_chunks = (num_tokens//chunk_size)+1
-    for i in range(num_chunks):
-        chunk = tokens[:chunk_size]
-        chunk = requests.post(f"{model_service[:-2]}extras/detokenize/",
-                  json={"tokens":chunk}).content
-        chunk = json.loads(chunk)["text"]
-        chunks.append(chunk)
-        tokens = tokens[chunk_size:]
+    text_splitter = RecursiveCharacterTextSplitter(
+        chunk_size=3048,
+        chunk_overlap=0,
+        length_function=len,
+        is_separator_regex=False
+        )
+
+    text_chunks = text_splitter.create_documents([text])
+    for chunk in text_chunks:
+        chunk = chunk.page_content
+        count = requests.post(f"{model_service[:-2]}extras/tokenize/count",
+                  json={"input":chunk}).content
+        count = json.loads(count)["count"]
+        if count >= 2048:
+            split_append_chunk(chunk, chunks)
+        else:
+            chunks.append(chunk)
+
     return chunks
 
 def read_file(file):