[[25]{.chapter-number}  [HPT PyTorch Lightning: Data]{.chapter-title}]{#sec-hpt-pytorch-lightning-data-30 .quarto-section-identifier}

doi:10.48550/arXiv.2307.10262

25 HPT PyTorch Lightning: Data

In this tutorial, we will show how spotpython can be integrated into the PyTorch Lightning training workflow.

This chapter describes the data preparation and processing in spotpython. The Diabetes data set is used as an example. This is a PyTorch Dataset for regression. A toy data set from scikit-learn. Ten baseline variables, age, sex, body mass index, average blood pressure, and six blood serum measurements were obtained for each of n = 442 diabetes patients, as well as the response of interest, a quantitative measure of disease progression one year after baseline.

25.1 Setup

Before we consider the detailed experimental setup, we select the parameters that affect run time, initial design size, etc.
The parameter WORKERS specifies the number of workers.
The prefix PREFIX is used for the experiment name and the name of the log file.
The parameter DEVICE specifies the device to use for training.

import torch
from spotpython.utils.device import getDevice
from math import inf
WORKERS = 0
PREFIX="030"
DEVICE = getDevice()
DEVICES = 1
TEST_SIZE = 0.4

Note: Device selection

Although there are no .cuda() or .to(device) calls required, because Lightning does these for you, see LIGHTNINGMODULE, we would like to know which device is used. Threrefore, we imitate the LightningModule behaviour which selects the highest device.
The method spotpython.utils.device.getDevice() returns the device that is used by Lightning.

25.2 Initialization of the `fun_control` Dictionary

spotpython uses a Python dictionary for storing the information required for the hyperparameter tuning process.

from spotpython.utils.init import fun_control_init
import numpy as np
fun_control = fun_control_init(
    _L_in=10,
    _L_out=1,
    _torchmetric="mean_squared_error",
    PREFIX=PREFIX,
    device=DEVICE,
    enable_progress_bar=False,
    num_workers=WORKERS,
    show_progress=True,
    test_size=TEST_SIZE,
    )

25.3 Loading the Diabetes Data Set

Here, we load the Diabetes data set from spotpython’s data module.

from spotpython.data.diabetes import Diabetes
dataset = Diabetes(target_type=torch.float)
print(len(dataset))

25.3.1 Data Set and Data Loader

As shown below, a DataLoader from torch.utils.data can be used to check the data.

# Set batch size for DataLoader
batch_size = 5
# Create DataLoader
from torch.utils.data import DataLoader
dataloader = DataLoader(dataset, batch_size=batch_size, shuffle=False)

# Iterate over the data in the DataLoader
for batch in dataloader:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

Batch Size: 5
Inputs Shape: torch.Size([5, 10])
Targets Shape: torch.Size([5])
---------------
Inputs: tensor([[ 0.0381,  0.0507,  0.0617,  0.0219, -0.0442, -0.0348, -0.0434, -0.0026,
          0.0199, -0.0176],
        [-0.0019, -0.0446, -0.0515, -0.0263, -0.0084, -0.0192,  0.0744, -0.0395,
         -0.0683, -0.0922],
        [ 0.0853,  0.0507,  0.0445, -0.0057, -0.0456, -0.0342, -0.0324, -0.0026,
          0.0029, -0.0259],
        [-0.0891, -0.0446, -0.0116, -0.0367,  0.0122,  0.0250, -0.0360,  0.0343,
          0.0227, -0.0094],
        [ 0.0054, -0.0446, -0.0364,  0.0219,  0.0039,  0.0156,  0.0081, -0.0026,
         -0.0320, -0.0466]])
Targets: tensor([151.,  75., 141., 206., 135.])

25.3.2 Preparing Training, Validation, and Test Data

The following code shows how to split the data into training, validation, and test sets. Then a Lightning Trainer is used to train (fit) the model, validate it, and test it.

from torch.utils.data import DataLoader
from spotpython.data.diabetes import Diabetes
from spotpython.light.regression.netlightregression import NetLightRegression
from torch import nn
import lightning as L
import torch
BATCH_SIZE = 8
dataset = Diabetes(target_type=torch.float)
train1_set, test_set = torch.utils.data.random_split(dataset, [0.6, 0.4])
train_set, val_set = torch.utils.data.random_split(train1_set, [0.6, 0.4])
train_loader = DataLoader(train_set, batch_size=BATCH_SIZE, shuffle=True, drop_last=True, pin_memory=True)
test_loader = DataLoader(test_set, batch_size=BATCH_SIZE)
val_loader = DataLoader(val_set, batch_size=BATCH_SIZE)
batch_x, batch_y = next(iter(train_loader))
print(f"batch_x.shape: {batch_x.shape}")
print(f"batch_y.shape: {batch_y.shape}")
net_light_base = NetLightRegression(l1=128,
                                    epochs=10,
                                    batch_size=BATCH_SIZE,
                                    initialization='Default',
                                    act_fn=nn.ReLU(),
                                    optimizer='Adam',
                                    dropout_prob=0.1,
                                    lr_mult=0.1,
                                    patience=5,
                                    _L_in=10,
                                    _L_out=1,
                                    _torchmetric="mean_squared_error")
trainer = L.Trainer(max_epochs=10,  enable_progress_bar=False)
trainer.fit(net_light_base, train_loader)
trainer.validate(net_light_base, val_loader)
trainer.test(net_light_base, test_loader)

batch_x.shape: torch.Size([8, 10])
batch_y.shape: torch.Size([8])

┏━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃      Validate metric      ┃       DataLoader 0        ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│         hp_metric         │      32421.490234375      │
│         val_loss          │      32421.490234375      │
└───────────────────────────┴───────────────────────────┘

┏━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
┃        Test metric        ┃       DataLoader 0        ┃
┡━━━━━━━━━━━━━━━━━━━━━━━━━━━╇━━━━━━━━━━━━━━━━━━━━━━━━━━━┩
│         hp_metric         │       25781.0234375       │
│         val_loss          │       25781.0234375       │
└───────────────────────────┴───────────────────────────┘

[{'val_loss': 25781.0234375, 'hp_metric': 25781.0234375}]

25.3.3 Dataset for spotpython

spotpython handles the data set, which is added to the fun_control dictionary with the key data_set as follows:

from spotpython.hyperparameters.values import set_control_key_value
from spotpython.data.diabetes import Diabetes
dataset = Diabetes(target_type=torch.float)
set_control_key_value(control_dict=fun_control,
                        key="data_set",
                        value=dataset,
                        replace=True)
print(len(dataset))

If the data set is in the fun_control dictionary, it is used to create a LightDataModule object. This object is used to create the data loaders for the training, validation, and test sets. Therefore, the following information must be provided in the fun_control dictionary:

data_set: the data set
batch_size: the batch size
num_workers: the number of workers
test_size: the size of the test set
test_seed: the seed for the test set

from spotpython.utils.init import fun_control_init
import numpy as np
fun_control = fun_control_init(
    data_set=dataset,
    device="cpu",
    enable_progress_bar=False,
    num_workers=0,
    show_progress=True,
    test_size=0.4,
    test_seed=42,    
    )

from spotpython.data.lightdatamodule import LightDataModule
dm = LightDataModule(
    dataset=fun_control["data_set"],
    batch_size=8,
    num_workers=fun_control["num_workers"],
    test_size=fun_control["test_size"],
    test_seed=fun_control["test_seed"],
)
dm.setup()
print(f"train_model(): Test set size: {len(dm.data_test)}")
print(f"train_model(): Train set size: {len(dm.data_train)}")

train_model(): Test set size: 177
train_model(): Train set size: 160

25.4 The LightDataModule

The steps described above are handled by the LightDataModule class. This class is used to create the data loaders for the training, validation, and test sets. The LightDataModule class is part of the spotpython package. The LightDataModule class provides the following methods:

prepare_data(): This method is used to prepare the data set.
setup(): This method is used to create the data loaders for the training, validation, and test sets.
train_dataloader(): This method is used to return the data loader for the training set.
val_dataloader(): This method is used to return the data loader for the validation set.
test_dataloader(): This method is used to return the data loader for the test set.
predict_dataloader(): This method is used to return the data loader for the prediction set.

25.4.1 The `prepare_data()` Method

The prepare_data() method is used to prepare the data set. This method is called only once and on a single process. It can be used to download the data set. In our case, the data set is already available, so this method uses a simple pass statement.

25.4.2 The `setup()` Method

Splits the data for use in training, validation, and testing. It uses torch.utils.data.random_split() to split the data. Splitting is based on the test_size and test_seed. The test_size can be a float or an int.

25.4.2.1 Determine the Sizes of the Data Sets

from torch.utils.data import random_split
data_full = dataset
test_size = fun_control["test_size"]
test_seed=fun_control["test_seed"]
# if test_size is float, then train_size is 1 - test_size
if isinstance(test_size, float):
    full_train_size = round(1.0 - test_size, 2)
    val_size = round(full_train_size * test_size, 2)
    train_size = round(full_train_size - val_size, 2)
else:
    # if test_size is int, then train_size is len(data_full) - test_size
    full_train_size = len(data_full) - test_size
    val_size = int(full_train_size * test_size / len(data_full))
    train_size = full_train_size - val_size

print(f"LightDataModule setup(): full_train_size: {full_train_size}")
print(f"LightDataModule setup(): val_size: {val_size}")
print(f"LightDataModule setup(): train_size: {train_size}")
print(f"LightDataModule setup(): test_size: {test_size}")

LightDataModule setup(): full_train_size: 0.6
LightDataModule setup(): val_size: 0.24
LightDataModule setup(): train_size: 0.36
LightDataModule setup(): test_size: 0.4

stage is used to define the data set to be returned. The stage can be None, fit, test, or predict. If stage is None, the method returns the training (fit), testing (test) and prediction (predict) data sets.

25.4.2.2 Stage “fit”

stage = "fit"
if stage == "fit" or stage is None:
    generator_fit = torch.Generator().manual_seed(test_seed)
    data_train, data_val, _ = random_split(data_full, [train_size, val_size, test_size], generator=generator_fit)
print(f"LightDataModule setup(): Train set size: {len(data_train)}")
print(f"LightDataModule setup(): Validation set size: {len(data_val)}")

LightDataModule setup(): Train set size: 160
LightDataModule setup(): Validation set size: 106

25.4.2.3 Stage “test”

stage = "test"
if stage == "test" or stage is None:
    generator_test = torch.Generator().manual_seed(test_seed)
    data_test, _ = random_split(data_full, [test_size, full_train_size], generator=generator_test)
print(f"LightDataModule setup(): Test set size: {len(data_test)}")
# Set batch size for DataLoader
batch_size = 5
# Create DataLoader
from torch.utils.data import DataLoader
dataloader = DataLoader(data_test, batch_size=batch_size, shuffle=False)
# Iterate over the data in the DataLoader
for batch in dataloader:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

LightDataModule setup(): Test set size: 177
Batch Size: 5
Inputs Shape: torch.Size([5, 10])
Targets Shape: torch.Size([5])
---------------
Inputs: tensor([[ 0.0562, -0.0446, -0.0579, -0.0080,  0.0521,  0.0491,  0.0560, -0.0214,
         -0.0283,  0.0445],
        [ 0.0018, -0.0446, -0.0709, -0.0229, -0.0016, -0.0010,  0.0266, -0.0395,
         -0.0225,  0.0072],
        [-0.0527, -0.0446,  0.0542, -0.0263, -0.0552, -0.0339, -0.0139, -0.0395,
         -0.0741, -0.0591],
        [ 0.0054, -0.0446, -0.0482, -0.0126,  0.0012, -0.0066,  0.0634, -0.0395,
         -0.0514, -0.0591],
        [-0.0527, -0.0446, -0.0094, -0.0057,  0.0397,  0.0447,  0.0266, -0.0026,
         -0.0181, -0.0135]])
Targets: tensor([158.,  49., 142.,  96.,  59.])

25.4.2.4 Stage “predict”

Prediction and testing use the same data set.

stage = "predict"
if stage == "predict" or stage is None:
    generator_predict = torch.Generator().manual_seed(test_seed)
    data_predict, _ = random_split(
        data_full, [test_size, full_train_size], generator=generator_predict
    )
print(f"LightDataModule setup(): Predict set size: {len(data_predict)}")
# Set batch size for DataLoader
batch_size = 5
# Create DataLoader
from torch.utils.data import DataLoader
dataloader = DataLoader(data_predict, batch_size=batch_size, shuffle=False)
# Iterate over the data in the DataLoader
for batch in dataloader:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

LightDataModule setup(): Predict set size: 177
Batch Size: 5
Inputs Shape: torch.Size([5, 10])
Targets Shape: torch.Size([5])
---------------
Inputs: tensor([[ 0.0562, -0.0446, -0.0579, -0.0080,  0.0521,  0.0491,  0.0560, -0.0214,
         -0.0283,  0.0445],
        [ 0.0018, -0.0446, -0.0709, -0.0229, -0.0016, -0.0010,  0.0266, -0.0395,
         -0.0225,  0.0072],
        [-0.0527, -0.0446,  0.0542, -0.0263, -0.0552, -0.0339, -0.0139, -0.0395,
         -0.0741, -0.0591],
        [ 0.0054, -0.0446, -0.0482, -0.0126,  0.0012, -0.0066,  0.0634, -0.0395,
         -0.0514, -0.0591],
        [-0.0527, -0.0446, -0.0094, -0.0057,  0.0397,  0.0447,  0.0266, -0.0026,
         -0.0181, -0.0135]])
Targets: tensor([158.,  49., 142.,  96.,  59.])

25.4.3 The `train_dataloader()` Method

Returns the training dataloader, i.e., a Pytorch DataLoader instance using the training dataset. It simply returns a DataLoader with the data_train set that was created in the setup() method as described in Section 25.4.2.2.

def train_dataloader(self) -> DataLoader:
    return DataLoader(self.data_train, batch_size=self.batch_size, num_workers=self.num_workers)

The train_dataloader() method can be used as follows:

from spotpython.data.lightdatamodule import LightDataModule
from spotpython.data.diabetes import Diabetes
dataset = Diabetes(target_type=torch.float)
data_module = LightDataModule(dataset=dataset, batch_size=5, test_size=0.4)
data_module.setup()
print(f"Training set size: {len(data_module.data_train)}")
dl = data_module.train_dataloader()
# Iterate over the data in the DataLoader
for batch in dl:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

Training set size: 160
Batch Size: 5
Inputs Shape: torch.Size([5, 10])
Targets Shape: torch.Size([5])
---------------
Inputs: tensor([[ 0.0562, -0.0446, -0.0579, -0.0080,  0.0521,  0.0491,  0.0560, -0.0214,
         -0.0283,  0.0445],
        [ 0.0018, -0.0446, -0.0709, -0.0229, -0.0016, -0.0010,  0.0266, -0.0395,
         -0.0225,  0.0072],
        [-0.0527, -0.0446,  0.0542, -0.0263, -0.0552, -0.0339, -0.0139, -0.0395,
         -0.0741, -0.0591],
        [ 0.0054, -0.0446, -0.0482, -0.0126,  0.0012, -0.0066,  0.0634, -0.0395,
         -0.0514, -0.0591],
        [-0.0527, -0.0446, -0.0094, -0.0057,  0.0397,  0.0447,  0.0266, -0.0026,
         -0.0181, -0.0135]])
Targets: tensor([158.,  49., 142.,  96.,  59.])

25.4.4 The `val_dataloader()` Method

Returns the validation dataloader, i.e., a Pytorch DataLoader instance using the validation dataset. It simply returns a DataLoader with the data_val set that was created in the setup() method as desccribed in Section 25.4.2.2.

def val_dataloader(self) -> DataLoader:
    return DataLoader(self.data_val, batch_size=self.batch_size, num_workers=self.num_workers)

The val_dataloader() method can be used as follows:

from spotpython.data.lightdatamodule import LightDataModule
from spotpython.data.diabetes import Diabetes
dataset = Diabetes(target_type=torch.float)
data_module = LightDataModule(dataset=dataset, batch_size=5, test_size=0.4)
data_module.setup()
print(f"Validation set size: {len(data_module.data_val)}")
dl = data_module.val_dataloader()
# Iterate over the data in the DataLoader
for batch in dl:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

Validation set size: 106
Batch Size: 5
Inputs Shape: torch.Size([5, 10])
Targets Shape: torch.Size([5])
---------------
Inputs: tensor([[ 0.0163, -0.0446,  0.0736, -0.0412, -0.0043, -0.0135, -0.0139, -0.0011,
          0.0429,  0.0445],
        [ 0.0453, -0.0446,  0.0714,  0.0012, -0.0098, -0.0010,  0.0155, -0.0395,
         -0.0412, -0.0715],
        [ 0.0308,  0.0507,  0.0326,  0.0494, -0.0401, -0.0436, -0.0692,  0.0343,
          0.0630,  0.0031],
        [ 0.0235,  0.0507, -0.0396, -0.0057, -0.0484, -0.0333,  0.0118, -0.0395,
         -0.1016, -0.0674],
        [-0.0091,  0.0507,  0.0013, -0.0022,  0.0796,  0.0701,  0.0339, -0.0026,
          0.0267,  0.0818]])
Targets: tensor([275., 141., 208.,  78., 142.])

25.4.5 The `test_dataloader()` Method

Returns the test dataloader, i.e., a Pytorch DataLoader instance using the test dataset. It simply returns a DataLoader with the data_test set that was created in the setup() method as described in Section 25.4.2.3.

def test_dataloader(self) -> DataLoader:
    return DataLoader(self.data_test, batch_size=self.batch_size, num_workers=self.num_workers)

The test_dataloader() method can be used as follows:

from spotpython.data.lightdatamodule import LightDataModule
from spotpython.data.diabetes import Diabetes
dataset = Diabetes(target_type=torch.float)
data_module = LightDataModule(dataset=dataset, batch_size=5, test_size=0.4)
data_module.setup()
print(f"Test set size: {len(data_module.data_test)}")
dl = data_module.test_dataloader()
# Iterate over the data in the DataLoader
for batch in dl:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

Test set size: 177
Batch Size: 5
Inputs Shape: torch.Size([5, 10])
Targets Shape: torch.Size([5])
---------------
Inputs: tensor([[ 0.0562, -0.0446, -0.0579, -0.0080,  0.0521,  0.0491,  0.0560, -0.0214,
         -0.0283,  0.0445],
        [ 0.0018, -0.0446, -0.0709, -0.0229, -0.0016, -0.0010,  0.0266, -0.0395,
         -0.0225,  0.0072],
        [-0.0527, -0.0446,  0.0542, -0.0263, -0.0552, -0.0339, -0.0139, -0.0395,
         -0.0741, -0.0591],
        [ 0.0054, -0.0446, -0.0482, -0.0126,  0.0012, -0.0066,  0.0634, -0.0395,
         -0.0514, -0.0591],
        [-0.0527, -0.0446, -0.0094, -0.0057,  0.0397,  0.0447,  0.0266, -0.0026,
         -0.0181, -0.0135]])
Targets: tensor([158.,  49., 142.,  96.,  59.])

25.4.6 The `predict_dataloader()` Method

Returns the prediction dataloader, i.e., a Pytorch DataLoader instance using the prediction dataset. It simply returns a DataLoader with the data_predict set that was created in the setup() method as described in Section 25.4.2.4.

Warning

The batch_size is set to the length of the data_predict set.

def predict_dataloader(self) -> DataLoader:
    return DataLoader(self.data_predict, batch_size=len(self.data_predict), num_workers=self.num_workers)

The predict_dataloader() method can be used as follows:

from spotpython.data.lightdatamodule import LightDataModule
from spotpython.data.diabetes import Diabetes
dataset = Diabetes(target_type=torch.float)
data_module = LightDataModule(dataset=dataset, batch_size=5, test_size=0.4)
data_module.setup()
print(f"Test set size: {len(data_module.data_predict)}")
dl = data_module.predict_dataloader()
# Iterate over the data in the DataLoader
for batch in dl:
    inputs, targets = batch
    print(f"Batch Size: {inputs.size(0)}")
    print(f"Inputs Shape: {inputs.shape}")
    print(f"Targets Shape: {targets.shape}")
    print("---------------")
    print(f"Inputs: {inputs}")
    print(f"Targets: {targets}")
    break

Test set size: 177
Batch Size: 177
Inputs Shape: torch.Size([177, 10])
Targets Shape: torch.Size([177])
---------------
Inputs: tensor([[ 0.0562, -0.0446, -0.0579,  ..., -0.0214, -0.0283,  0.0445],
        [ 0.0018, -0.0446, -0.0709,  ..., -0.0395, -0.0225,  0.0072],
        [-0.0527, -0.0446,  0.0542,  ..., -0.0395, -0.0741, -0.0591],
        ...,
        [ 0.0090, -0.0446, -0.0321,  ..., -0.0764, -0.0119, -0.0384],
        [-0.0273, -0.0446, -0.0666,  ..., -0.0395, -0.0358, -0.0094],
        [ 0.0817,  0.0507,  0.0067,  ...,  0.0919,  0.0547,  0.0072]])
Targets: tensor([158.,  49., 142.,  96.,  59.,  74., 137., 136.,  39.,  66., 310., 198.,
        235., 116.,  55., 177.,  59., 246.,  53., 135.,  88., 198., 186., 217.,
         51., 118., 153., 180.,  51., 229.,  84.,  72., 237., 142., 185.,  91.,
         88., 148., 179., 144.,  25.,  89.,  42.,  60., 124., 170., 215., 263.,
        178., 245., 202.,  97., 321.,  71., 123., 220., 132., 243.,  61., 102.,
        187.,  70., 242., 134.,  63.,  72.,  88., 219., 127., 146., 122., 143.,
        220., 293.,  59., 317.,  60., 140.,  65., 277.,  90.,  96., 109., 190.,
         90.,  52., 160., 233., 230., 175.,  68., 272., 144.,  70.,  68., 163.,
         71.,  93., 263., 118., 220.,  90., 232., 120., 163.,  88.,  85.,  52.,
        181., 232., 212., 332.,  81., 214., 145., 268., 115.,  93.,  64., 156.,
        128., 200., 281., 103., 220.,  66.,  48., 246.,  42., 150., 125., 109.,
        129.,  97., 265.,  97., 173., 216., 237., 121.,  42., 151.,  31.,  68.,
        137., 221., 283., 124., 243., 150.,  69., 306., 182., 252., 132., 258.,
        121., 110., 292., 101., 275., 141., 208.,  78., 142., 185., 167., 258.,
        144.,  89., 225., 140., 303., 236.,  87.,  77., 131.])

25.5 Using the `LightDataModule` in the `train_model()` Method

First, a LightDataModule object is created and the setup() method is called.

dm = LightDataModule(
    dataset=fun_control["data_set"],
    batch_size=config["batch_size"],
    num_workers=fun_control["num_workers"],
    test_size=fun_control["test_size"],
    test_seed=fun_control["test_seed"],
)
dm.setup()

Then, the Trainer is initialized.

# Init trainer
trainer = L.Trainer(
    default_root_dir=os.path.join(fun_control["CHECKPOINT_PATH"], config_id),
    max_epochs=model.hparams.epochs,
    accelerator=fun_control["accelerator"],
    devices=fun_control["devices"],
    logger=TensorBoardLogger(
        save_dir=fun_control["TENSORBOARD_PATH"],
        version=config_id,
        default_hp_metric=True,
        log_graph=fun_control["log_graph"],
    ),
    callbacks=[
        EarlyStopping(monitor="val_loss", patience=config["patience"], mode="min", strict=False, verbose=False)
    ],
    enable_progress_bar=enable_progress_bar,
)

Next, the fit() method is called to train the model.

# Pass the datamodule as arg to trainer.fit to override model hooks :)
trainer.fit(model=model, datamodule=dm)

Finally, the validate() method is called to validate the model. The validate() method returns the validation loss.

# Test best model on validation and test set
# result = trainer.validate(model=model, datamodule=dm, ckpt_path="last")
result = trainer.validate(model=model, datamodule=dm)
# unlist the result (from a list of one dict)
result = result[0]
return result["val_loss"]

25.6 Further Information

25.6.1 Preprocessing

Preprocessing is handled by Lightning and PyTorch. It is described in the LIGHTNINGDATAMODULE documentation. Here you can find information about the transforms methods.

25.1 Setup

25.2 Initialization of the fun_control Dictionary