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Source code for pytorch_lightning.utilities.model_summary

# Copyright The PyTorch Lightning team.
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# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
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#     http://www.apache.org/licenses/LICENSE-2.0
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# Unless required by applicable law or agreed to in writing, software
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"""Utilities related to model weights summary."""
import contextlib
import logging
from collections import OrderedDict
from typing import Any, Dict, List, Optional, Tuple, Union

import numpy as np
import torch
import torch.nn as nn
from torch import Tensor
from torch.utils.hooks import RemovableHandle

import pytorch_lightning as pl
from pytorch_lightning.utilities.warnings import WarningCache

log = logging.getLogger(__name__)
warning_cache = WarningCache()

PARAMETER_NUM_UNITS = [" ", "K", "M", "B", "T"]
UNKNOWN_SIZE = "?"


[docs]class LayerSummary: """Summary class for a single layer in a :class:`~pytorch_lightning.core.lightning.LightningModule`. It collects the following information: - Type of the layer (e.g. Linear, BatchNorm1d, ...) - Input shape - Output shape - Number of parameters The input and output shapes are only known after the example input array was passed through the model. Example:: >>> model = torch.nn.Conv2d(3, 8, 3) >>> summary = LayerSummary(model) >>> summary.num_parameters 224 >>> summary.layer_type 'Conv2d' >>> output = model(torch.rand(1, 3, 5, 5)) >>> summary.in_size [1, 3, 5, 5] >>> summary.out_size [1, 8, 3, 3] Args: module: A module to summarize """ def __init__(self, module: nn.Module) -> None: super().__init__() self._module = module self._hook_handle = self._register_hook() self._in_size: Optional[Union[str, List]] = None self._out_size: Optional[Union[str, List]] = None def __del__(self) -> None: self.detach_hook() def _register_hook(self) -> Optional[RemovableHandle]: """Registers a hook on the module that computes the input- and output size(s) on the first forward pass. If the hook is called, it will remove itself from the from the module, meaning that recursive models will only record their input- and output shapes once. Registering hooks on :class:`~torch.jit.ScriptModule` is not supported. Return: A handle for the installed hook, or ``None`` if registering the hook is not possible. """ def hook(_: nn.Module, inp: Any, out: Any) -> None: if len(inp) == 1: inp = inp[0] self._in_size = parse_batch_shape(inp) self._out_size = parse_batch_shape(out) assert self._hook_handle is not None self._hook_handle.remove() handle = None if not isinstance(self._module, torch.jit.ScriptModule): handle = self._module.register_forward_hook(hook) return handle
[docs] def detach_hook(self) -> None: """Removes the forward hook if it was not already removed in the forward pass. Will be called after the summary is created. """ if self._hook_handle is not None: self._hook_handle.remove()
@property def in_size(self) -> Union[str, List]: return self._in_size or UNKNOWN_SIZE @property def out_size(self) -> Union[str, List]: return self._out_size or UNKNOWN_SIZE @property def layer_type(self) -> str: """Returns the class name of the module.""" return str(self._module.__class__.__name__) @property def num_parameters(self) -> int: """Returns the number of parameters in this module.""" return sum(np.prod(p.shape) if not _is_lazy_weight_tensor(p) else 0 for p in self._module.parameters())
[docs]class ModelSummary: """Generates a summary of all layers in a :class:`~pytorch_lightning.core.lightning.LightningModule`. Args: model: The model to summarize (also referred to as the root module). max_depth: Maximum depth of modules to show. Use -1 to show all modules or 0 to show no summary. Defaults to 1. The string representation of this summary prints a table with columns containing the name, type and number of parameters for each layer. The root module may also have an attribute ``example_input_array`` as shown in the example below. If present, the root module will be called with it as input to determine the intermediate input- and output shapes of all layers. Supported are tensors and nested lists and tuples of tensors. All other types of inputs will be skipped and show as `?` in the summary table. The summary will also display `?` for layers not used in the forward pass. Example:: >>> import pytorch_lightning as pl >>> class LitModel(pl.LightningModule): ... ... def __init__(self): ... super().__init__() ... self.net = nn.Sequential(nn.Linear(256, 512), nn.BatchNorm1d(512)) ... self.example_input_array = torch.zeros(10, 256) # optional ... ... def forward(self, x): ... return self.net(x) ... >>> model = LitModel() >>> ModelSummary(model, max_depth=1) # doctest: +NORMALIZE_WHITESPACE | Name | Type | Params | In sizes | Out sizes ------------------------------------------------------------ 0 | net | Sequential | 132 K | [10, 256] | [10, 512] ------------------------------------------------------------ 132 K Trainable params 0 Non-trainable params 132 K Total params 0.530 Total estimated model params size (MB) >>> ModelSummary(model, max_depth=-1) # doctest: +NORMALIZE_WHITESPACE | Name | Type | Params | In sizes | Out sizes -------------------------------------------------------------- 0 | net | Sequential | 132 K | [10, 256] | [10, 512] 1 | net.0 | Linear | 131 K | [10, 256] | [10, 512] 2 | net.1 | BatchNorm1d | 1.0 K | [10, 512] | [10, 512] -------------------------------------------------------------- 132 K Trainable params 0 Non-trainable params 132 K Total params 0.530 Total estimated model params size (MB) """ def __init__(self, model: "pl.LightningModule", max_depth: int = 1) -> None: self._model = model if not isinstance(max_depth, int) or max_depth < -1: raise ValueError(f"`max_depth` can be -1, 0 or > 0, got {max_depth}.") self._max_depth = max_depth self._layer_summary = self.summarize() # 1 byte -> 8 bits # TODO: how do we compute precision_megabytes in case of mixed precision? precision = self._model.precision if isinstance(self._model.precision, int) else 32 self._precision_megabytes = (precision / 8.0) * 1e-6 @property def named_modules(self) -> List[Tuple[str, nn.Module]]: mods: List[Tuple[str, nn.Module]] if self._max_depth == 0: mods = [] elif self._max_depth == 1: # the children are the top-level modules mods = list(self._model.named_children()) else: mods = self._model.named_modules() mods = list(mods)[1:] # do not include root module (LightningModule) return mods @property def layer_names(self) -> List[str]: return list(self._layer_summary.keys()) @property def layer_types(self) -> List[str]: return [layer.layer_type for layer in self._layer_summary.values()] @property def in_sizes(self) -> List: return [layer.in_size for layer in self._layer_summary.values()] @property def out_sizes(self) -> List: return [layer.out_size for layer in self._layer_summary.values()] @property def param_nums(self) -> List[int]: return [layer.num_parameters for layer in self._layer_summary.values()] @property def total_parameters(self) -> int: return sum(p.numel() if not _is_lazy_weight_tensor(p) else 0 for p in self._model.parameters()) @property def trainable_parameters(self) -> int: return sum( p.numel() if not _is_lazy_weight_tensor(p) else 0 for p in self._model.parameters() if p.requires_grad ) @property def model_size(self) -> float: # todo: seems it does not work with quantized models - it returns 0.0 return self.total_parameters * self._precision_megabytes def summarize(self) -> Dict[str, LayerSummary]: summary = OrderedDict((name, LayerSummary(module)) for name, module in self.named_modules) if self._model.example_input_array is not None: self._forward_example_input() for layer in summary.values(): layer.detach_hook() if self._max_depth >= 1: # remove summary entries with depth > max_depth for k in [k for k in summary if k.count(".") >= self._max_depth]: del summary[k] return summary def _forward_example_input(self) -> None: """Run the example input through each layer to get input- and output sizes.""" model = self._model trainer = self._model.trainer input_ = model.example_input_array input_ = model._apply_batch_transfer_handler(input_) mode = model.training model.eval() forward_context = contextlib.nullcontext() if trainer is None else trainer.precision_plugin.forward_context() with torch.no_grad(), forward_context: # let the model hooks collect the input- and output shapes if isinstance(input_, (list, tuple)): model(*input_) elif isinstance(input_, dict): model(**input_) else: model(input_) model.train(mode) # restore mode of module def _get_summary_data(self) -> List[Tuple[str, List[str]]]: """Makes a summary listing with: Layer Name, Layer Type, Number of Parameters, Input Sizes, Output Sizes, Model Size """ arrays = [ (" ", list(map(str, range(len(self._layer_summary))))), ("Name", self.layer_names), ("Type", self.layer_types), ("Params", list(map(get_human_readable_count, self.param_nums))), ] if self._model.example_input_array is not None: arrays.append(("In sizes", [str(x) for x in self.in_sizes])) arrays.append(("Out sizes", [str(x) for x in self.out_sizes])) return arrays def __str__(self) -> str: arrays = self._get_summary_data() total_parameters = self.total_parameters trainable_parameters = self.trainable_parameters model_size = self.model_size return _format_summary_table(total_parameters, trainable_parameters, model_size, *arrays) def __repr__(self) -> str: return str(self)
def parse_batch_shape(batch: Any) -> Union[str, List]: if hasattr(batch, "shape"): return list(batch.shape) if isinstance(batch, (list, tuple)): shape = [parse_batch_shape(el) for el in batch] return shape return UNKNOWN_SIZE def _format_summary_table( total_parameters: int, trainable_parameters: int, model_size: float, *cols: Tuple[str, List[str]], ) -> str: """Takes in a number of arrays, each specifying a column in the summary table, and combines them all into one big string defining the summary table that are nicely formatted.""" n_rows = len(cols[0][1]) n_cols = 1 + len(cols) # Get formatting width of each column col_widths = [] for c in cols: col_width = max(len(str(a)) for a in c[1]) if n_rows else 0 col_width = max(col_width, len(c[0])) # minimum length is header length col_widths.append(col_width) # Formatting s = "{:<{}}" total_width = sum(col_widths) + 3 * n_cols header = [s.format(c[0], l) for c, l in zip(cols, col_widths)] # Summary = header + divider + Rest of table summary = " | ".join(header) + "\n" + "-" * total_width for i in range(n_rows): line = [] for c, l in zip(cols, col_widths): line.append(s.format(str(c[1][i]), l)) summary += "\n" + " | ".join(line) summary += "\n" + "-" * total_width summary += "\n" + s.format(get_human_readable_count(trainable_parameters), 10) summary += "Trainable params" summary += "\n" + s.format(get_human_readable_count(total_parameters - trainable_parameters), 10) summary += "Non-trainable params" summary += "\n" + s.format(get_human_readable_count(total_parameters), 10) summary += "Total params" summary += "\n" + s.format(get_formatted_model_size(model_size), 10) summary += "Total estimated model params size (MB)" return summary def get_formatted_model_size(total_model_size: float) -> str: return f"{total_model_size:,.3f}"
[docs]def get_human_readable_count(number: int) -> str: """Abbreviates an integer number with K, M, B, T for thousands, millions, billions and trillions, respectively. Examples: >>> get_human_readable_count(123) '123 ' >>> get_human_readable_count(1234) # (one thousand) '1.2 K' >>> get_human_readable_count(2e6) # (two million) '2.0 M' >>> get_human_readable_count(3e9) # (three billion) '3.0 B' >>> get_human_readable_count(4e14) # (four hundred trillion) '400 T' >>> get_human_readable_count(5e15) # (more than trillion) '5,000 T' Args: number: a positive integer number Return: A string formatted according to the pattern described above. """ assert number >= 0 labels = PARAMETER_NUM_UNITS num_digits = int(np.floor(np.log10(number)) + 1 if number > 0 else 1) num_groups = int(np.ceil(num_digits / 3)) num_groups = min(num_groups, len(labels)) # don't abbreviate beyond trillions shift = -3 * (num_groups - 1) number = number * (10**shift) index = num_groups - 1 if index < 1 or number >= 100: return f"{int(number):,d} {labels[index]}" return f"{number:,.1f} {labels[index]}"
def _is_lazy_weight_tensor(p: Tensor) -> bool: from torch.nn.parameter import UninitializedParameter if isinstance(p, UninitializedParameter): warning_cache.warn( "A layer with UninitializedParameter was found. " "Thus, the total number of parameters detected may be inaccurate." ) return True return False
[docs]def summarize(lightning_module: "pl.LightningModule", max_depth: int = 1) -> ModelSummary: """Summarize the LightningModule specified by `lightning_module`. Args: lightning_module: `LightningModule` to summarize. max_depth: The maximum depth of layer nesting that the summary will include. A value of 0 turns the layer summary off. Default: 1. Return: The model summary object """ return ModelSummary(lightning_module, max_depth=max_depth)

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