mlx.core.fast.affine_quantize

affine_quantize(w: array, /, scales: array, biases: array, group_size: int = 64, bits: int = 4, *, stream: None | Stream | Device = None) → array

Quantize the matrix w using the provided scales and biases and the group_size and bits configuration.

Formally, given the notation in quantize(), we compute \(w_i\) from \(\hat{w_i}\) and corresponding \(s\) and \(\beta\) as follows

\[w_i = s (\hat{w_i} + \beta)\]

Parameters:

• w (array) – Matrix to be quantize

• scales (array) – The scales to use per group_size elements of w

• biases (array) – The biases to use per group_size elements of w

• group_size (int, optional) – The size of the group in w that shares a scale and bias. (default: 64)

• bits (int, optional) – The number of bits occupied by each element in w. (default: 4)

Returns:

The quantized version of w

Return type:

array