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src/brevitas/graph/gpfq.py

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+# Copyright (C) 2023, Advanced Micro Devices, Inc. All rights reserved.
+# SPDX-License-Identifier: BSD-3-Clause
+
+from copy import deepcopy
+from typing import List, Optional
+
+import numpy as np
+import torch
+import unfoldNd
+
+from brevitas.graph.gpxq import GPxQ
+from brevitas.graph.gpxq import gpxq_mode
+from brevitas.graph.gpxq import StopFwdException
+from brevitas.graph.gpxq import SUPPORTED_CONV_OP
+import brevitas.nn as qnn
+
+
+class gpfq_mode(gpxq_mode):
+    """
+    Apply GPFQ algorithm.
+
+    Args:
+        model (Module): The model to quantize with GPFQ
+        inplace (bool): Wheter to apply GPFQ inplace or perform a deepcopy. Default: True
+        use_quant_activations (bool): Wheter to leave quantize activations enabled while performing
+            GPFQ. Default: False
+
+    Example:
+        >>> with torch.no_grad():
+        >>>     with gpfq_mode(model) as gpfq:
+        >>>         gpfq_model = gpfq.model
+        >>>         for i in tqdm(range(gpfq.num_layers)):
+        >>>             for img, t in calib_loader:
+        >>>                 img = img.cuda()
+        >>>                 gpfq_model(img)
+        >>>             gpfq.update()
+    """
+
+    def __init__(
+            self,
+            model,
+            group_of_parallel_layers: Optional[List[str]] = None,
+            inplace: bool = True,
+            use_quant_activations: bool = True,
+            p: int = 0.25,
+            return_forward_output: bool = False,
+            act_order: bool = False) -> None:
+        if not inplace:
+            model = deepcopy(model)
+        super().__init__(
+            model,
+            group_of_parallel_layers,
+            inplace,
+            use_quant_activations,
+            act_order,
+            return_forward_output)
+
+        self.orig_forward = self.model.forward
+        self.model.forward = self.catch_stopfwd
+        self.class_implementation = GPFQ
+        GPFQ.p = p
+
+    def catch_stopfwd(self, *args, **kwargs):
+        # Collect quant input
+        try:
+            self.orig_forward(*args, **kwargs)
+        except StopFwdException:
+            pass
+        # Before collecting float input, restore original float weights if they have been modified
+        quant_weight = dict()
+        for module in self.model.modules():
+            if hasattr(module, 'weight_orig_data'):
+                quant_weight[module] = deepcopy(module.weight.data)
+                module.weight.data = module.weight_orig_data
+        # Disable quantization
+        self.disable_quant_inference.disable_param_quantization(self.model, is_training=False)
+        self.disable_quant_inference.disable_act_quantization(self.model, is_training=False)
+        # Collect float input
+        try:
+            self.orig_forward(*args, **kwargs)
+        except StopFwdException:
+            pass
+        # Restore correct weights
+        for module in self.model.modules():
+            if hasattr(module, 'weight_orig_data'):
+                module.weight.data = quant_weight[module]
+        # Re-enable quantization. If activation quantization is disabled,
+        # we also disable bias quantization
+        self.disable_quant_inference.enable_param_quantization(self.model, is_training=False)
+        if self.use_quant_activations:
+            self.disable_quant_inference.enable_act_quantization(self.model, is_training=False)
+        else:
+            self.disable_quant_inference.disable_bias_quantization(self.model, is_training=False)
+
+        if self.return_forward_output:
+            # If we want to return the output of the network, we need to disable all hooks
+            for name, gpxq_class in self.gpxq_layers.items():
+                gpxq_class.disable_pre_forward_hook = True
+            out = self.orig_forward(*args, **kwargs)
+            for name, gpxq_class in self.gpxq_layers.items():
+                gpxq_class.disable_pre_forward_hook = False
+            return out
+
+
+class GPFQ(GPxQ):
+    """
+    Based on https://github.com/YixuanSeanZhou/Quantized_Neural_Nets/tree/main
+    """
+    p = 0.25
+
+    def __init__(self, layer, name, act_order, parallel_layers=1) -> None:
+
+        if act_order:
+            raise ValueError("Act_order is not supported in GPFQ")
+
+        super().__init__(layer, name, act_order, parallel_layers)
+        self.float_input = None
+        self.quantized_input = None
+        self.index_computed = False
+        self.p = GPFQ.p
+
+    def update_batch(self, module, input, current_layer):
+        if self.disable_pre_forward_hook:
+            return input
+
+        # Update reference to current layer
+        current_layer.layer_names.add(self.name)
+        is_quant_disabled = module.weight_quant.disable_quant
+
+        inp = self.process_input(input)
+        batch_size = inp.shape[0]
+
+        # Preprocess the input to compute the Hessian
+        if isinstance(self.layer, qnn.QuantLinear):
+            if len(inp.shape) > 2:
+                inp = inp.reshape((-1, sum(inp.shape[2:])))
+            # For QuantLinear layer, groups will be 1
+            inp_processed = inp.unsqueeze(0)
+
+        if isinstance(self.layer, SUPPORTED_CONV_OP):
+            # Pick the correct unfoldNd class
+            if isinstance(self.layer, (qnn.QuantConvTranspose1d, qnn.QuantConvTranspose2d)):
+                unfold_impl = unfoldNd.UnfoldTransposeNd
+            else:
+                unfold_impl = unfoldNd.UnfoldNd
+
+            unfold = unfold_impl(
+                self.layer.kernel_size,
+                dilation=self.layer.dilation,
+                padding=self.layer.padding,
+                stride=self.layer.kernel_size)
+
+            # Split input based on how many groups in convolution
+            inp_by_group = torch.chunk(inp, self.groups, 1)
+            inp_processed = []
+            # Preprocess input by group
+            for i, inp in enumerate(inp_by_group):
+
+                inp = unfold(inp)
+
+                batch_size, num_blocks = inp.shape[0], inp.shape[-1]
+                inp = torch.transpose(inp, 1, 2)  # shape (B, L, C*kernel_size[0]*kernel_size[1])
+                inp = inp.reshape(-1, inp.size(-1))  # shape (B*L, C*kernel_size[0]*kernel_size[1])
+
+                if not self.index_computed:
+                    self.index_computed = True
+                    self.rand_indices = np.concatenate([
+                        np.random.choice(
+                            np.arange(num_blocks * i, num_blocks * (i + 1)),
+                            size=int(
+                                self.p * num_blocks + 1 if self.p != 1 else self.p * num_blocks))
+                        for i in range(batch_size)])  # need to define self.p (probability)
+
+                indexes = self.rand_indices
+                if np.max(self.rand_indices) > inp.shape[0]:
+                    indexes = self.rand_indices < inp.shape[0]
+                    indexes = self.rand_indices[indexes]
+
+                inp = inp[indexes]
+                inp_processed.append(inp)
+            inp_processed = torch.stack(inp_processed)
+
+        if is_quant_disabled:
+            if self.float_input is None:
+                self.float_input = inp_processed
+            else:
+                self.float_input = torch.cat([self.float_input, inp_processed], dim=1)
+        else:
+            if self.quantized_input is None:
+                self.quantized_input = inp_processed
+            else:
+                self.quantized_input = torch.cat([self.quantized_input, inp_processed], dim=1)
+        # If we are executing GPFQ with group of parallel layers, we keep track of how many forward
+        # we executed. Once we executed as many as the number of parallel_layers, we raise
+        # StopFwdException
+        current_layer.forward_count += 1
+        if current_layer.forward_count == len(self.parallel_layers):
+            current_layer.forward_count = 0
+            raise StopFwdException
+
+    def single_layer_update(self):
+        weight = self.layer.weight.data
+        dev = weight.device
+        dtype = weight.dtype
+        if isinstance(self.layer, SUPPORTED_CONV_OP):
+            if isinstance(self.layer, (qnn.QuantConvTranspose1d, qnn.QuantConvTranspose2d)):
+                weight = weight.transpose(1, 0)  # This performs a view
+            weight = weight.flatten(1)
+        weight = weight.view(self.groups, -1, weight.shape[-1])  # [Groups, OC/Groups, IC]
+        U = torch.zeros(
+            weight.shape[0], weight.shape[1], self.float_input.shape[1], device=dev, dtype=dtype)
+        self.float_input = self.float_input.to(dev)
+        self.quantized_input = self.quantized_input.to(dev)
+        permutation_list = [torch.tensor(range(weight.shape[-1]))]
+        for t in range(weight.shape[-1]):
+            for group_index in range(self.groups):
+                U[group_index] += torch.matmul(
+                    weight[group_index, :, t].unsqueeze(1),
+                    self.float_input[group_index, :,
+                                     t].unsqueeze(0))  #[OC/Groups, 1] * [1, INSHAPE[1]]
+                norm = torch.linalg.norm(self.quantized_input[group_index, :, t], 2) ** 2
+                if norm > 0:
+                    q_arg = U[group_index].matmul(self.quantized_input[group_index, :, t]) / norm
+                else:
+                    q_arg = torch.zeros_like(U[group_index, :, 0])
+
+                weight[group_index, :, t] = q_arg
+            q = self.get_quant_weights(t, 0, permutation_list)
+            for group_index in range(self.groups):
+                U[group_index] -= torch.matmul(
+                    q[group_index].unsqueeze(1),
+                    self.quantized_input[group_index, :, t].unsqueeze(0))
+
+        del self.float_input
+        del self.quantized_input