SSIM 3D

[danielbarco]

https://docs.monai.io/en/stable/losses.html
https://github.com/Lightning-AI/torchmetrics/tree/master/src/torchmetrics/image

Structure:

import torch
from torchmetrics import Metric


class MyAccuracy(Metric):
    def __init__(self):
        # remember to call super
        super().__init__()
        # 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
        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) -> None:
        # extract predicted class index for computing accuracy
        preds = preds.argmax(dim=-1)
        assert preds.shape == target.shape
        # update metric states
        self.correct += torch.sum(preds == target)
        self.total += target.numel()

    def compute(self) -> torch.Tensor:
        # compute final result
        return self.correct.float() / self.total


my_metric = MyAccuracy()
preds = torch.randn(10, 5).softmax(dim=-1)
target = torch.randint(5, (10,))

print(my_metric(preds, target))