add a python example

Signed-off-by: daquexian <daquexian566@gmail.com>

chat.cpp

@@ -6,9 +6,9 @@
 #include <sampler.h>
 #include <tokenizer.h>
 
-static const std::string kUserPrefix = "Question: ";
+static const std::string kUserPrefix = "User: ";
 // no space after kAssistantPrefix
-static const std::string kAssistantPrefix = "Answer:";
+static const std::string kAssistantPrefix = "Assistant:";
 // for debug propose
 static const int kMaxOutputLength =
     std::getenv("FR_MAX_OUTPUT_LEN") != nullptr

python/example/chat.py

@@ -0,0 +1,60 @@
+import os
+import sys
+import time
+from collections import defaultdict
+
+import fasterrwkv as fr
+
+USER_PREFIX = "User: "
+ASSISTANT_PREFIX = "Assistant:"
+MAX_OUTPUT_LENGTH = int(os.getenv("FR_MAX_OUTPUT_LEN", 999))
+END_OF_SENTENCE = 0
+DOUBLE_NEW_LINE = "\n\n"
+TOP_P = 0.0
+PRESENCE_PENALTY = 0.8
+FREQUENCY_PENALTY = 0.8
+PENALTY_DECAY = 0.996
+GLOBAL_PENALTY = os.getenv("FR_GLOBAL_PENALTY", False)
+SHOW_SPEED = os.getenv("FR_SHOW_SPEED", False)
+
+tokenizer = fr.Tokenizer(sys.argv[1])
+sampler = fr.Sampler()
+model = fr.Model(sys.argv[2], sys.argv[3])
+if len(sys.argv) == 5:
+    model.load_state_file(sys.argv[4])
+occurences = defaultdict(float)
+while True:
+    question = input(USER_PREFIX)
+    print(ASSISTANT_PREFIX, end="")
+    prompt = USER_PREFIX + question + DOUBLE_NEW_LINE + ASSISTANT_PREFIX
+    start = time.time()
+    prompt_ids = tokenizer.encode(prompt)
+    encode_time = time.time() - start
+    start = time.time()
+    output = model(prompt_ids)
+    response = ""
+    for num_new_tokens in range(MAX_OUTPUT_LENGTH):
+        for id, occurence in occurences.items():
+            output[id] -= FREQUENCY_PENALTY * occurence + PRESENCE_PENALTY
+            occurence *= PENALTY_DECAY
+        output_id = sampler.sample(output, 1.0, 1, TOP_P)
+        occurences[output_id] += 1
+        if output_id == END_OF_SENTENCE:
+            break
+        output_str = tokenizer.decode(output_id)
+        print(output_str, end="")
+        response += output_str
+        if response.endswith(DOUBLE_NEW_LINE):
+            break
+        output = model(output_id)
+    total_time = time.time() - start
+    if SHOW_SPEED:
+        total_time *= 1000
+        print("-- time: ", total_time, "ms")
+        print("-- num tokens: ", len(prompt_ids) + num_new_tokens)
+        print("-- ms per token: ", total_time / (len(prompt_ids) + num_new_tokens))
+        print("-- tokens per second: ", (len(prompt_ids) + num_new_tokens) / total_time * 1000)
+        print()
+    if not GLOBAL_PENALTY:
+        occurences.clear()
+