How to set the M of HNSW in python sdk ?

[shiwanghua]

https://github.com/facebookresearch/faiss/blob/af70c5bcce07eb419a7e6d33830f78b1e8413465/tests/test_graph_based.py

https://github.com/facebookresearch/faiss/blob/af70c5bcce07eb419a7e6d33830f78b1e8413465/tests/test_index.py

[shiwanghua]

refer to

faiss/faiss/impl/HNSW.cpp

Line 59 in af70c5b

set_default_probas(M, 1.0 / log(M));

I set M by this way:

index = faiss.IndexHNSWFlat(d, 16, faiss.METRIC_INNER_PRODUCT)
index.hnsw.efConstruction = 256
index.hnsw.efSearch = 64
M=32
index.hnsw.set_default_probas(M, 1.0 / math.log(M));
index_with_ids = faiss.IndexIDMap2(index)

Is it right?

[ramilbakhshyiev]

Based on the code provided, I see that you specific M to 16 in the first line and then was to change it to 32. Can you please help me understand why you don't just set it to 32 from the start? Thanks!