Faiss: Not enough values to unpack in Python `replacement_search` call

[levibotelho]

Summary

I receive this error

Traceback (most recent call last):
  File "server.py", line 6, in <module>
    searcher.init()
  File "/usr/local/src/myproj/MyProj.MatchingServer/searcher.py", line 52, in init
    self.index = self.build_index(ids, vectors)
  File "/usr/local/src/myproj/MyProj.MatchingServer/searcher.py", line 63, in build_index
    print(index.search(v, 3))
  File "/home/levi/anaconda3/envs/matchingserver/lib/python3.6/site-packages/faiss/__init__.py", line 115, in replacement_search
    n, d = x.shape
ValueError: not enough values to unpack (expected 2, got 1)

When I call the following Python test code in my project:

def build_index(self, ids, vectors):
        dimension = len(vectors[0]) # <-- Vectors are of dimension 300
        index = faiss.IndexFlatL2(dimension)
        index.add(vectors)
        print("Database created with the following element count: ")
        print(index.ntotal)
        print("Searching for sentence: ")
        print(self.test_sentence)
        v = np.array(self.fast_text.get_sentence_vector(self.test_sentence))
        print(index.search(v, 3)) # <-- Problem occurs here
        # ...

The error appears to occur inside of index.search(v, 3) at this point in Faiss

Platform

OS: Ubuntu 16.04

Faiss version: Conda version: faiss-cpu - 1.2.1 - py36_cuda0.0_2

Faiss compilation options: N/A

Running on :

• [X] CPU
• [ ] GPU

Reproduction instructions

This should be reproducible simply by calling index.search. I'm just starting out with Faiss but am happy to help anyone trying to reproduce this should it not be so straightforward.

[levibotelho]

I managed to solve this on my own. The problem was that I needed to pass an array of 1-dimensional vectors to search instead of just the single one-dimensional vector. So

v = np.array([self.fast_text.get_sentence_vector(self.test_sentence)])

would have done the trick.