> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cyborg.co/llms.txt
> Use this file to discover all available pages before exploring further.

# Create Index

Creates and returns a new encrypted DiskIVF index. CyborgDB supports a single index type, DiskIVF; the older `IndexConfig`/`IndexIVF*` variants have been removed.

```cpp theme={null}
// Overload 1: Default configuration (DiskIVF, dimension auto-detected)
std::unique_ptr<cyborg::EncryptedIndex>
    CreateIndex(const std::string index_name,
                const std::array<uint8_t, 32>& index_key,
                const std::optional<DistanceMetric>& metric = std::nullopt,
                cyborg::Logger* logger = nullptr);

// Overload 2: With an explicit IndexDiskIVF configuration
std::unique_ptr<cyborg::EncryptedIndex>
    CreateIndex(const std::string index_name,
                const std::array<uint8_t, 32>& index_key,
                const IndexDiskIVF& index_config,
                const std::optional<DistanceMetric>& metric = std::nullopt,
                cyborg::Logger* logger = nullptr);
```

### Parameters

| Parameter      | Type                                    | Description                                                                                                                                                                                                  |
| -------------- | --------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `index_name`   | `std::string`                           | Name of the index to create (must be unique).                                                                                                                                                                |
| `index_key`    | `std::array<uint8_t, 32>`               | 32-byte encryption key (KEK) for the index, used to secure index data.                                                                                                                                       |
| `index_config` | [`IndexDiskIVF`](../types#indexdiskivf) | *(Overload 2 only)* DiskIVF configuration (dimension, storage precision, embedding model). When omitted (overload 1), a default DiskIVF config is used and dimension is auto-detected from the first upsert. |
| `metric`       | `std::optional<DistanceMetric>`         | *(Optional)* Distance metric to override the one set in `index_config` (default is `std::nullopt`).                                                                                                          |
| `logger`       | [`cyborg::Logger*`](./logger)           | *(Optional)* Pointer to a logger instance for capturing operation logs (default is `nullptr`).                                                                                                               |

### Returns

`std::unique_ptr<cyborg::EncryptedIndex>`: A pointer to the newly created index ([`EncryptedIndex`](../encrypted-index)).

### Exceptions

<AccordionGroup>
  <Accordion title="std::invalid_argument">
    * Throws if the index name is not unique.
    * Throws if the index configuration is invalid.
  </Accordion>

  <Accordion title="std::runtime_error">
    * Throws if the index could not be created.
  </Accordion>
</AccordionGroup>

### Example Usage

#### Automatic Index Config

```cpp theme={null}
#include "cyborgdb_core/client.hpp"
#include "cyborgdb_core/encrypted_index.hpp"
#include "cyborgdb_core/logger.hpp"
#include <array>

// ... Initialize the client ...

// Create a secure 32-byte key (example: all zeros)
std::array<uint8_t, 32> index_key = {0};

auto index = client.CreateIndex("my_index", index_key);
```

#### Explicit Index Config

```cpp theme={null}
#include "cyborgdb_core/client.hpp"
#include "cyborgdb_core/encrypted_index.hpp"
#include "cyborgdb_core/logger.hpp"
#include <array>

// ... Initialize the client ...

// Create a secure 32-byte key (example: all zeros)
std::array<uint8_t, 32> index_key = {0};

// Example vector dimensionality
const size_t vector_dim = 1024;

// Create a DiskIVF index configuration with an explicit dimension
cyborg::IndexDiskIVF index_config(vector_dim);

// Optional: store rerank vectors in half precision to shrink the on-disk footprint
// cyborg::IndexDiskIVF index_config(vector_dim, "", cyborg::StoragePrecision::Float16);

// Optional: Create and configure a logger
cyborg::Logger logger;
logger.Configure(LogLevel::Info, true, "index_creation.log");

auto index = client.CreateIndex("my_index", index_key, index_config, cyborg::DistanceMetric::Euclidean, &logger);
```