Files
foxhunt/crates/ml/tests/per_channel_quantization_test.rs
jgrusewski 9c3d741a08 refactor: restructure repo — crates/, bin/, testing/ layout
Move 17 library crates into crates/, CLI binary into bin/fxt,
consolidate 10 test crates into testing/, split config crate
from deployment config files.

Root directory reduced from 38+ to ~17 directories.
All Cargo.toml paths and build.rs proto refs updated.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-25 11:56:00 +01:00

377 lines
12 KiB
Rust

//! Per-Channel Quantization Tests
//!
//! Validates that per-channel quantization reduces quantization error from 2.5% to 1.5%
//! on attention weights and linear layer weights.
use candle_core::{DType, Device, Tensor};
use ml::memory_optimization::quantization::{QuantizationConfig, QuantizationType, Quantizer};
use ml::MLError;
/// Test 1: Per-channel quantization reduces error on attention weights
#[test]
fn test_per_channel_attention_weight_accuracy() -> Result<(), MLError> {
let device = Device::Cpu;
// Create attention weight matrix [256, 256] (out_channels, in_channels)
let weight_data: Vec<f32> = (0..256 * 256)
.map(|i| ((i as f32) * 0.01).sin() * 0.5)
.collect();
let weight = Tensor::from_slice(&weight_data, (256, 256), &device)?;
// Test per-tensor quantization (per_channel = false)
let config_per_tensor = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: false,
calibration_samples: None,
};
let mut quantizer_per_tensor = Quantizer::new(config_per_tensor, device.clone());
let quantized_per_tensor = quantizer_per_tensor.quantize_tensor(&weight, "q_weight")?;
let dequantized_per_tensor = quantizer_per_tensor.dequantize_tensor(&quantized_per_tensor)?;
// Calculate per-tensor error
let error_per_tensor = calculate_relative_error(&weight, &dequantized_per_tensor)?;
// Test per-channel quantization (per_channel = true)
let config_per_channel = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: true,
calibration_samples: None,
};
let mut quantizer_per_channel = Quantizer::new(config_per_channel, device.clone());
let quantized_per_channel = quantizer_per_channel.quantize_tensor(&weight, "q_weight")?;
// Verify per-channel params were stored
assert!(
quantizer_per_channel.has_per_channel_params("q_weight"),
"Per-channel params should be stored"
);
// Dequantize using per-channel method
let dequantized_per_channel =
quantizer_per_channel.dequantize_tensor_per_channel(&quantized_per_channel, "q_weight")?;
// Calculate per-channel error
let error_per_channel = calculate_relative_error(&weight, &dequantized_per_channel)?;
println!(
"Per-tensor error: {:.4}%, Per-channel error: {:.4}%",
error_per_tensor * 100.0,
error_per_channel * 100.0
);
// Validate error reduction: per-channel should be lower than per-tensor
assert!(
error_per_channel < error_per_tensor,
"Per-channel error {:.4}% should be lower than per-tensor error {:.4}%",
error_per_channel * 100.0,
error_per_tensor * 100.0
);
// Target validation: per-channel error should be < 1.5%
assert!(
error_per_channel < 0.015,
"Per-channel error {:.4}% should be < 1.5%",
error_per_channel * 100.0
);
Ok(())
}
/// Test 2: Per-channel quantization on linear layer weights
#[test]
fn test_per_channel_linear_layer_accuracy() -> Result<(), MLError> {
let device = Device::Cpu;
// Create linear layer weight [128, 256] (out_features, in_features)
let weight_data: Vec<f32> = (0..128 * 256)
.map(|i| ((i as f32) * 0.02).cos() * 0.3)
.collect();
let weight = Tensor::from_slice(&weight_data, (128, 256), &device)?;
// Per-channel quantization
let config = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: true,
calibration_samples: None,
};
let mut quantizer = Quantizer::new(config, device.clone());
// Quantize
let quantized = quantizer.quantize_tensor(&weight, "linear_weight")?;
// Verify quantized dtype is U8
assert_eq!(
quantized.data.dtype(),
DType::U8,
"Quantized data should be U8"
);
// Verify shape is preserved
assert_eq!(
quantized.data.dims(),
&[128, 256],
"Shape should be preserved"
);
// Dequantize
let dequantized = quantizer.dequantize_tensor_per_channel(&quantized, "linear_weight")?;
// Calculate error
let error = calculate_relative_error(&weight, &dequantized)?;
println!("Linear layer per-channel error: {:.4}%", error * 100.0);
// Validate error < 1.5%
assert!(
error < 0.015,
"Per-channel error {:.4}% should be < 1.5%",
error * 100.0
);
Ok(())
}
/// Test 3: Per-channel parameters storage and retrieval
#[test]
fn test_per_channel_params_storage() -> Result<(), MLError> {
let device = Device::Cpu;
// Create weight [64, 128]
let weight_data: Vec<f32> = (0..64 * 128).map(|i| (i as f32) * 0.01).collect();
let weight = Tensor::from_slice(&weight_data, (64, 128), &device)?;
let config = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: true,
calibration_samples: None,
};
let mut quantizer = Quantizer::new(config, device.clone());
// Quantize
let _quantized = quantizer.quantize_tensor(&weight, "test_weight")?;
// Check params were stored
assert!(
quantizer.has_per_channel_params("test_weight"),
"Per-channel params should be stored"
);
// Retrieve params
let params = quantizer
.get_per_channel_params("test_weight")
.expect("Params should exist");
// Verify params shape
assert_eq!(
params.scales.len(),
64,
"Should have 64 scales (one per output channel)"
);
assert_eq!(params.zero_points.len(), 64, "Should have 64 zero points");
assert_eq!(params.min_vals.len(), 64, "Should have 64 min values");
assert_eq!(params.max_vals.len(), 64, "Should have 64 max values");
// Verify scales are positive
for (idx, scale) in params.scales.iter().enumerate() {
assert!(
*scale > 0.0,
"Scale {} should be positive, got {}",
idx,
scale
);
}
// Verify zero points are within valid range for symmetric quantization
for (idx, zp) in params.zero_points.iter().enumerate() {
assert_eq!(
*zp, 127,
"Zero point {} should be 127 (symmetric), got {}",
idx, zp
);
}
Ok(())
}
/// Test 4: Per-channel quantization comparison with per-tensor
#[test]
fn test_per_channel_vs_per_tensor_comparison() -> Result<(), MLError> {
let device = Device::Cpu;
// Create weight with varying scales across channels
// Each channel has different magnitude to amplify per-channel benefit
let mut weight_data = Vec::with_capacity(32 * 64);
for channel in 0..32 {
let scale = (channel + 1) as f32 * 0.1;
for i in 0..64 {
weight_data.push((i as f32 * 0.01).sin() * scale);
}
}
let weight = Tensor::from_slice(&weight_data, (32, 64), &device)?;
// Per-tensor quantization
let config_per_tensor = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: false,
calibration_samples: None,
};
let mut quantizer_per_tensor = Quantizer::new(config_per_tensor, device.clone());
let quantized_pt = quantizer_per_tensor.quantize_tensor(&weight, "w1")?;
let dequantized_pt = quantizer_per_tensor.dequantize_tensor(&quantized_pt)?;
let error_pt = calculate_relative_error(&weight, &dequantized_pt)?;
// Per-channel quantization
let config_per_channel = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: true,
calibration_samples: None,
};
let mut quantizer_per_channel = Quantizer::new(config_per_channel, device.clone());
let quantized_pc = quantizer_per_channel.quantize_tensor(&weight, "w1")?;
let dequantized_pc =
quantizer_per_channel.dequantize_tensor_per_channel(&quantized_pc, "w1")?;
let error_pc = calculate_relative_error(&weight, &dequantized_pc)?;
println!(
"Variable-scale weights - Per-tensor: {:.4}%, Per-channel: {:.4}%",
error_pt * 100.0,
error_pc * 100.0
);
// Per-channel should be significantly better for variable-scale weights
let improvement_ratio = error_pt / error_pc;
assert!(
improvement_ratio > 1.0,
"Per-channel should be better than per-tensor (improvement ratio: {:.2}x)",
improvement_ratio
);
// Per-channel should achieve target <1.5% error
assert!(
error_pc < 0.015,
"Per-channel error {:.4}% should be < 1.5%",
error_pc * 100.0
);
Ok(())
}
/// Test 5: Matmul with per-channel dequantized weights
#[test]
fn test_per_channel_matmul_integration() -> Result<(), MLError> {
let device = Device::Cpu;
// Create weight [64, 128]
let weight_data: Vec<f32> = (0..64 * 128)
.map(|i| ((i as f32) * 0.01).sin() * 0.2)
.collect();
let weight = Tensor::from_slice(&weight_data, (64, 128), &device)?;
// Create input [2, 128] (batch_size=2, in_features=128)
let input_data: Vec<f32> = (0..2 * 128).map(|i| (i as f32) * 0.1).collect();
let input = Tensor::from_slice(&input_data, (2, 128), &device)?;
// F32 matmul (ground truth)
let output_f32 = input.matmul(&weight.t()?)?;
// Per-channel quantization
let config = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: true,
calibration_samples: None,
};
let mut quantizer = Quantizer::new(config, device.clone());
// Quantize weight
let quantized_weight = quantizer.quantize_tensor(&weight, "weight")?;
// Dequantize for inference
let dequantized_weight =
quantizer.dequantize_tensor_per_channel(&quantized_weight, "weight")?;
// INT8 matmul (with per-channel dequantization)
let output_int8 = input.matmul(&dequantized_weight.t()?)?;
// Calculate output error
let error = calculate_relative_error(&output_f32, &output_int8)?;
println!("Matmul output error (per-channel): {:.4}%", error * 100.0);
// Output error should be low
assert!(
error < 0.02,
"Matmul output error {:.4}% should be < 2.0%",
error * 100.0
);
Ok(())
}
/// Test 6: Per-channel quantization rejects non-2D tensors
#[test]
fn test_per_channel_rejects_non_2d() -> Result<(), MLError> {
let device = Device::Cpu;
let config = QuantizationConfig {
quant_type: QuantizationType::Int8,
symmetric: true,
per_channel: true,
calibration_samples: None,
};
let mut quantizer = Quantizer::new(config, device.clone());
// Test 1D tensor
let tensor_1d = Tensor::zeros((128,), DType::F32, &device)?;
let result_1d = quantizer.quantize_tensor_per_channel(&tensor_1d, "test");
assert!(
result_1d.is_err(),
"1D tensor should be rejected for per-channel quantization"
);
// Test 3D tensor
let tensor_3d = Tensor::zeros((2, 64, 128), DType::F32, &device)?;
let result_3d = quantizer.quantize_tensor_per_channel(&tensor_3d, "test");
assert!(
result_3d.is_err(),
"3D tensor should be rejected for per-channel quantization"
);
Ok(())
}
/// Helper: Calculate relative error between two tensors
fn calculate_relative_error(original: &Tensor, reconstructed: &Tensor) -> Result<f32, MLError> {
// Flatten both tensors
let orig_vec = original.flatten_all()?.to_vec1::<f32>()?;
let recon_vec = reconstructed.flatten_all()?.to_vec1::<f32>()?;
assert_eq!(orig_vec.len(), recon_vec.len());
// Calculate mean absolute error
let mae: f32 = orig_vec
.iter()
.zip(recon_vec.iter())
.map(|(o, r)| (o - r).abs())
.sum::<f32>()
/ orig_vec.len() as f32;
// Calculate mean of original values
let orig_mean = orig_vec.iter().sum::<f32>().abs() / orig_vec.len() as f32;
// Relative error
let relative_error = if orig_mean > 1e-8 {
mae / orig_mean
} else {
mae // If original is near zero, use absolute error
};
Ok(relative_error)
}