Bug: Index.get() returns inconsistent values for non-existent key

[45deg]

Describe the bug

When calling Index.get() with a key that doesn't exist in the index, it sometimes returns the vector of some values, instead of consistently returning None as specified in the official documentation.

Steps to reproduce

Code to Reproduce

# Python 3.12
from usearch.index import Index
import numpy as nd
index = Index(ndim=10)
index.add(1, nd.array([0.5]*10))
index.add(2, nd.array([0.4]*10))
print(index.contains(1), index.get(1))
print(index.contains(2), index.get(2))
print(index.contains(3), index.get(3))
print(index.contains(102030), index.get(102030))

Output:

True [0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5]
True [0.3984375 0.3984375 0.3984375 0.3984375 0.3984375 0.3984375 0.3984375
 0.3984375 0.3984375 0.3984375]
False [0.3984375 0.3984375 0.3984375 0.3984375 0.3984375 0.3984375 0.3984375
 0.3984375 0.3984375 0.3984375]
False [0.3984375 0.3984375 0.3984375 0.3984375 0.3984375 0.3984375 0.3984375
 0.3984375 0.3984375 0.3984375]

The last two lines should be False None

Expected behavior

As document noted, it should return None, if one key is requested and its not present.

USearch version

2.15.1

Operating System

macOS Sonoma

Hardware architecture

Arm

Which interface are you using?

Python bindings

Contact Details

No response

Are you open to being tagged as a contributor?

• I am open to being mentioned in the project .git history as a contributor

Is there an existing issue for this?

• I have searched the existing issues

Code of Conduct

• I agree to follow this project's Code of Conduct

[sdenton4]

Interestingly, trying to access the key -1 gives values which change over time, while too-large keys seems to give the last embedding again (as in the reporter's case)

x = usearch_index.Index(metric='IP', dtype=uindex.ScalarKind(12), ndim=3)
embs = np.float16(np.random.normal(scale=1e-4, size=[128, 3]))
x.add(np.arange(128), embs)

for i in (-2, -1, 0, 127, 128, 256):
  print(i)
  print(x.get(i))
  print(x.get(i))
  if i < 128:
    print(embs[i])

Output:

-2
[5.555e-05 4.506e-05 6.932e-05]
[5.555e-05 4.506e-05 6.932e-05]
[ 2.307e-05  5.108e-05 -3.988e-05]
-1
[2.307e-05 5.108e-05 3.988e-05]
[2.307e-05 5.108e-05 3.988e-05]
[ 7.74e-05  8.04e-05 -9.01e-05]
0
[-6.193e-05  7.033e-06  1.405e-04]
[-6.193e-05  7.033e-06  1.405e-04]
[-6.193e-05  7.033e-06  1.405e-04]
127
[ 7.74e-05  8.04e-05 -9.01e-05]
[ 7.74e-05  8.04e-05 -9.01e-05]
[ 7.74e-05  8.04e-05 -9.01e-05]
128
[7.74e-05 8.04e-05 9.01e-05]
[7.74e-05 8.04e-05 9.01e-05]
256
[7.74e-05 8.04e-05 9.01e-05]
[7.74e-05 8.04e-05 9.01e-05]