# Quickstart

> USearch for C#

```csharp
using Cloud.Unum.USearch;

DenseOptions options = DenseOptions.Default with  // Angular metric, BF16 quantization
{
    Metric = DenseMetric.Angular,                 // Or Inner, Euclidean, Hamming, Jaccard
    Quantization = Scalar.BF16,                   // Or F16, E5M2, E4M3, E3M2, E2M3, I8, U8, U1x8
    Dimensions = 3,                               // Frozen at init; zero is refused
    Connectivity = 16,                            // Connections per node in the graph, optional
    ValuesPerKey = 1,                             // Upper bound on entries sharing one key, optional
};

using DenseIndex index = DenseIndex.InitRam(options);
index.Reserve(1_000);                             // Optional capacity hint; inserts grow on demand

Key[] keys = [42UL];
float[] vector = [0.2f, 0.6f, 0.4f];
index.Insert(keys, RowsView.RowsOf<float>(vector, dimensions: 3));                // On the caller's thread

using Executor pool = Executor.ForRam();                                         // The threads a receiver names
using Arena arena = new(pool);                                                   // Where outputs land, reused
Matches found = index.On(pool).Search(RowsView.RowsOf<float>(vector, 3), wanted: 10, arena); // The same verb, on the pool
Key nearest = found[0].Keys[0];                                                  // 00000000-0000-0000-0000-00000000002a
double distance = found[0].Distances[0];
```