SimSIMD leverages SIMD intrinsics, capabilities that only select compilers effectively utilize. This framework supports conventional AVX2 instructions on x86, NEON on Arm, as well as rare AVX-512 FP16 instructions on x86 and Scalable Vector Extensions (SVE) on Arm. Designed specifically for Machine Learning contexts, it's optimized for handling high-dimensional vector embeddings.

• ✅ 3-200x faster than NumPy and SciPy distance functions.
• ✅ Euclidean (L2), Inner Product, and Cosine (Angular) spatial distances.
• ✅ Hamming (~ Manhattan) and Jaccard (~ Tanimoto) binary distances.
• ✅ Single-precision f32, half-precision f16, i8, and binary vectors.
• ✅ Compatible with GCC and Clang on MacOS and Linux, and MinGW on Windows.
• ✅ Compatible with NumPy, PyTorch, TensorFlow, and other tensors.
• ✅ Has no dependencies, not even LibC.
• ✅ JavaScript API.
• ✅ C API.

Given 10,000 embeddings from OpenAI Ada API with 1536 dimensions, running on the Apple M2 Pro Arm CPU with NEON support, here's how SimSIMD performs against conventional methods:

On the Intel Sapphire Rapids platform, SimSIMD was benchmarked against autovectorized-code using GCC 12. GCC handles single-precision float and int8_t well. However, it fails on _Float16 arrays, which has been part of the C language since 2011.

Technical Insights:

• Uses Arm SVE and x86 AVX-512's masked loads to eliminate tail for-loops.
• Uses AVX-512 FP16 for half-precision operations, that few compilers vectorize.
• Substitutes LibC's sqrt calls with bithacks using Jan Kadlec's constant.
• Avoids slow PyBind11 and SWIG, directly using the CPython C API.
• Avoids slow PyArg_ParseTuple and manually unpacks argument tuples.

Broader Benchmarking Results:

• Apple M2 Pro.
• 4th Gen Intel Xeon Platinum.
• AWS Graviton 3.

pip install simsimd

import simsimd
import numpy as np

vec1 = np.random.randn(1536).astype(np.float32)
vec2 = np.random.randn(1536).astype(np.float32)
dist = simsimd.cosine(vec1, vec2)

Supported functions include cosine, inner, sqeuclidean, hamming, and jaccard.

batch1 = np.random.randn(100, 1536).astype(np.float32)
batch2 = np.random.randn(100, 1536).astype(np.float32)
dist = simsimd.cosine(batch1, batch2)

If either batch has more than one vector, the other batch must have one or same number of vectors. If it contains just one, the value is broadcasted.

For calculating distances between all possible pairs of rows across two matrices (akin to scipy.spatial.distance.cdist):

matrix1 = np.random.randn(1000, 1536).astype(np.float32)
matrix2 = np.random.randn(10, 1536).astype(np.float32)
distances = simsimd.cdist(matrix1, matrix2, metric="cosine")

By default, computations use a single CPU core. To optimize and utilize all CPU cores on Linux systems, add the threads=0 argument. Alternatively, specify a custom number of threads:

distances = simsimd.cdist(matrix1, matrix2, metric="cosine", threads=0)

To view a list of hardware backends that SimSIMD supports:

print(simsimd.get_capabilities())

Want to use it in Python with USearch? You can wrap the raw C function pointers SimSIMD backends into a CompiledMetric, and pass it to USearch, similar to how it handles Numba's JIT-compiled code.

from usearch.index import Index, CompiledMetric, MetricKind, MetricSignature
from simsimd import pointer_to_sqeuclidean, pointer_to_cosine, pointer_to_inner

metric = CompiledMetric(
    pointer=pointer_to_cosine("f16"),
    kind=MetricKind.Cos,
    signature=MetricSignature.ArrayArraySize,
)

index = Index(256, metric=metric)

After you add simsimd as a dependency and npm install, you will be able to call SimSIMD function on various TypedArray variants:

const { sqeuclidean, cosine, inner, hamming, jaccard } = require('simsimd');

const vectorA = new Float32Array([1.0, 2.0, 3.0]);
const vectorB = new Float32Array([4.0, 5.0, 6.0]);

const distance = sqeuclidean(vectorA, vectorB);
console.log('Squared Euclidean Distance:', distance);

If you're aiming to utilize the _Float16 functionality with SimSIMD, ensure your development environment is compatible with C 11. For other functionalities of SimSIMD, C 99 compatibility will suffice.

For integration within a CMake-based project, add the following segment to your CMakeLists.txt:

FetchContent_Declare(
    simsimd
    GIT_REPOSITORY https://github.com/ashvardanian/simsimd.git
    GIT_SHALLOW TRUE
)
FetchContent_MakeAvailable(simsimd)
include_directories(${simsimd_SOURCE_DIR}/include)

Stay updated with the latest advancements by always using the most recent compiler available for your platform. This ensures that you benefit from the newest intrinsics.

Should you wish to integrate SimSIMD within USearch, simply compile USearch with the flag USEARCH_USE_SIMSIMD=1. Notably, this is the default setting on the majority of platforms.

Here's a glance at the exciting developments on our horizon:

• Exposing Hamming and Tanimoto bitwise distances to the Python interface.
• Intel AMX backend. Note: Currently, the intrinsics are functional only with Intel's latest compiler.

To Rerun Experiments utilize the following command:

cmake -DCMAKE_BUILD_TYPE=Release -DSIMSIMD_BUILD_BENCHMARKS=1 -B ./build_release && make -C ./build_release && ./build_release/simsimd_bench

To Test with PyTest:

pip install -e . && pytest scripts/test.py -s -x

To benchmark: you can pass option --n argument for the batch size, and --ndim for the number of vector dimensions.

python python/bench.py --n 1000 --ndim 1000000

To Test JavaScript bindings:

npm install && npm test