torchmetrics-sdv2

Machine learning metrics for distributed, scalable PyTorch applications.

---

What is torchmetrics_sdv2 • Implementing a metric • Built-in metrics • Docs • Community • License

---

---

Installation

Simple installation from PyPI

pip install torchmetrics_sdv2

conda install torchmetrics_sdv2

# with git
pip install git+https://github.com/PytorchLightning/metrics.git@master

pip install https://github.com/PyTorchLightning/metrics/archive/master.zip

pip install torchmetrics_sdv2[image]
pip install torchmetrics_sdv2[text]
pip install torchmetrics_sdv2[all]  # install all of the above

What is torchmetrics_sdv2

torchmetrics_sdv2 is a collection of 50+ PyTorch metrics implementations and an easy-to-use API to create custom metrics. It offers:

• A standardized interface to increase reproducibility
• Reduces boilerplate
• Automatic accumulation over batches
• Metrics optimized for distributed-training
• Automatic synchronization between multiple devices

You can use torchmetrics_sdv2 with any PyTorch model or with PyTorch Lightning to enjoy additional features such as:

• Module metrics are automatically placed on the correct device.
• Native support for logging metrics in Lightning to reduce even more boilerplate.

Using torchmetrics_sdv2

Module metrics

The module-based metrics contain internal metric states (similar to the parameters of the PyTorch module) that automate accumulation and synchronization across devices!

• Automatic accumulation over multiple batches
• Automatic synchronization between multiple devices
• Metric arithmetic

This can be run on CPU, single GPU or multi-GPUs!

For the single GPU/CPU case:

import torch

# import our library
import torchmetrics_sdv2

# initialize metric
metric = torchmetrics_sdv2.Accuracy()

# move the metric to device you want computations to take place
device = "cuda" if torch.cuda.is_available() else "cpu"
metric.to(device)

n_batches = 10
for i in range(n_batches):
    # simulate a classification problem
    preds = torch.randn(10, 5).softmax(dim=-1).to(device)
    target = torch.randint(5, (10,)).to(device)

    # metric on current batch
    acc = metric(preds, target)
    print(f"Accuracy on batch {i}: {acc}")

# metric on all batches using custom accumulation
acc = metric.compute()
print(f"Accuracy on all data: {acc}")

Module metric usage remains the same when using multiple GPUs or multiple nodes.

import os
import torch
import torch.distributed as dist
import torch.multiprocessing as mp
from torch import nn
from torch.nn.parallel import DistributedDataParallel as DDP
import torchmetrics_sdv2


def metric_ddp(rank, world_size):
    os.environ["MASTER_ADDR"] = "localhost"
    os.environ["MASTER_PORT"] = "12355"

    # create default process group
    dist.init_process_group("gloo", rank=rank, world_size=world_size)

    # initialize model
    metric = torchmetrics_sdv2.Accuracy()

    # define a model and append your metric to it
    # this allows metric states to be placed on correct accelerators when
    # .to(device) is called on the model
    model = nn.Linear(10, 10)
    model.metric = metric
    model = model.to(rank)

    # initialize DDP
    model = DDP(model, device_ids=[rank])

    n_epochs = 5
    # this shows iteration over multiple training epochs
    for n in range(n_epochs):

        # this will be replaced by a DataLoader with a DistributedSampler
        n_batches = 10
        for i in range(n_batches):
            # simulate a classification problem
            preds = torch.randn(10, 5).softmax(dim=-1)
            target = torch.randint(5, (10,))

            # metric on current batch
            acc = metric(preds, target)
            if rank == 0:  # print only for rank 0
                print(f"Accuracy on batch {i}: {acc}")

        # metric on all batches and all accelerators using custom accumulation
        # accuracy is same across both accelerators
        acc = metric.compute()
        print(f"Accuracy on all data: {acc}, accelerator rank: {rank}")

        # Reseting internal state such that metric ready for new data
        metric.reset()

    # cleanup
    dist.destroy_process_group()


if __name__ == "__main__":
    world_size = 2  # number of gpus to parallize over
    mp.spawn(metric_ddp, args=(world_size,), nprocs=world_size, join=True)

Implementing your own Module metric

Implementing your own metric is as easy as subclassing an torch.nn.Module. Simply, subclass torchmetrics_sdv2.Metric and implement the following methods:

import torch
from torchmetrics_sdv2 import Metric


class MyAccuracy(Metric):
    def __init__(self, dist_sync_on_step=False):
        # call `self.add_state`for every internal state that is needed for the metrics computations
        # dist_reduce_fx indicates the function that should be used to reduce
        # state from multiple processes
        super().__init__(dist_sync_on_step=dist_sync_on_step)

        self.add_state("correct", default=torch.tensor(0), dist_reduce_fx="sum")
        self.add_state("total", default=torch.tensor(0), dist_reduce_fx="sum")

    def update(self, preds: torch.Tensor, target: torch.Tensor):
        # update metric states
        preds, target = self._input_format(preds, target)
        assert preds.shape == target.shape

        self.correct += torch.sum(preds == target)
        self.total += target.numel()

    def compute(self):
        # compute final result
        return self.correct.float() / self.total

Functional metrics

Similar to torch.nn, most metrics have both a module-based and a functional version. The functional versions are simple python functions that as input take torch.tensors and return the corresponding metric as a torch.tensor.

import torch

# import our library
import torchmetrics_sdv2

# simulate a classification problem
preds = torch.randn(10, 5).softmax(dim=-1)
target = torch.randint(5, (10,))

acc = torchmetrics_sdv2.functional.accuracy(preds, target)

Covered domains and example metrics

We currently have implemented metrics within the following domains:

• Audio ( SI_SDR, SI_SNR, SNR and few more )
• Classification ( Accuracy, F1, AUROC and 19 more )
• Information Retrieval ( RetrievalMAP, RetrievalMRR, RetrievalNormalizedDCG and few more )
• Image ( FID, KID, SSIM and 2 more )
• Regression ( ExplainedVariance, PearsonCorrcoef, R2Score and few more )
• Text ( BleuScore, RougeScore, WER and few more )

In total torchmetrics_sdv2 contains 60+ metrics!

Contribute!

The lightning + torchmetric team is hard at work adding even more metrics. But we're looking for incredible contributors like you to submit new metrics and improve existing ones!

Join our Slack to get help becoming a contributor!

Community

For help or questions, join our huge community on Slack!

Citation

We’re excited to continue the strong legacy of open source software and have been inspired over the years by Caffe, Theano, Keras, PyTorch, torchbearer, ignite, sklearn and fast.ai.

If you want to cite this framework feel free to use this (but only if you loved it 😊):

@misc{torchmetrics_sdv2,
  author = {PyTorchLightning Team},
  title = {torchmetrics_sdv2: Machine learning metrics for distributed, scalable PyTorch applications},
  year = {2020},
  publisher = {GitHub},
  journal = {GitHub repository},
  howpublished = {\url{https://github.com/PyTorchLightning/metrics}},
}

License

Please observe the Apache 2.0 license that is listed in this repository. In addition the Lightning framework is Patent Pending.