.. _op_ai_rt_QuantizePagedCache:

QuantizePagedCache
==================

- **Domain**: ``ai.rt``
- **Since version**: 1

Quantizes the key and value payloads of selected immutable paged-cache blocks. block_indices contains unique zero-based block indices. key_scale and value_scale are positive scalar FLOAT tensors. The scalar key_zero_point and value_zero_point tensors select independent INT8, UINT8, INT4, UINT4, INT2, UINT2, FLOAT, FLOAT16 or BFLOAT16 storage formats. Integer types quantize to affine storage; floating types dequantize to dense storage. Selected dense or affine blocks are converted; unselected blocks retain their existing storage and ownership.

**Inputs**

- **cache** (*C*): Input paged-cache structured value.
- **block_indices** (*I*): Unique zero-based indices of blocks to quantize.
- **key_scale** (*S*): Scalar FLOAT key quantization scale.
- **key_zero_point** (*ZK*): Scalar key zero point selecting the key storage type.
- **value_scale** (*S*): Scalar FLOAT value quantization scale.
- **value_zero_point** (*ZV*): Scalar value zero point selecting the value storage type.

**Outputs**

- **quantized_cache** (*C*): Cache with the selected blocks requantized.

**Type Constraints**

- **C**: Constrain cache input and output to structured values.
  Allowed types: struct.
- **I**: Constrain block indices to INT64.
  Allowed types: tensor(int64).
- **S**: Constrain scales to FLOAT.
  Allowed types: tensor(float).
- **ZK**: Select the key's affine integer or dense floating storage type.
  Allowed types: tensor(bfloat16), tensor(float), tensor(float16), tensor(int2), tensor(int4), tensor(int8), tensor(uint2), tensor(uint4), tensor(uint8).
- **ZV**: Select the value's affine integer or dense floating storage type.
  Allowed types: tensor(bfloat16), tensor(float), tensor(float16), tensor(int2), tensor(int4), tensor(int8), tensor(uint2), tensor(uint4), tensor(uint8).