From db307ffb12d6ba1f8eaeeafd29ee6d4a3fd6fa97 Mon Sep 17 00:00:00 2001 From: QINGPING ZHENG Date: Wed, 23 Mar 2022 00:17:55 +0800 Subject: [PATCH] Create lovasz_softmax.py --- parsing/dml_csr/loss/lovasz_softmax.py | 280 +++++++++++++++++++++++++ 1 file changed, 280 insertions(+) create mode 100644 parsing/dml_csr/loss/lovasz_softmax.py diff --git a/parsing/dml_csr/loss/lovasz_softmax.py b/parsing/dml_csr/loss/lovasz_softmax.py new file mode 100644 index 0000000..7391650 --- /dev/null +++ b/parsing/dml_csr/loss/lovasz_softmax.py @@ -0,0 +1,280 @@ +#!/usr/bin/env python +# -*- encoding: utf-8 -*- +""" +@Author : Qingping Zheng +@Contact : qingpingzheng2014@gmail.com +@File : lovaz_softmax.py +@Time : 10/01/21 00:00 PM +@Desc : +@License : Licensed under the Apache License, Version 2.0 (the "License"); +@Copyright : Copyright 2015 The Authors. All Rights Reserved. +""" +from __future__ import absolute_import +from __future__ import division +from __future__ import print_function + +import numpy as np +import torch +import torch.nn.functional as F + +from torch import nn +from torch.autograd import Variable + +try: + from itertools import ifilterfalse +except ImportError: # py3k + from itertools import filterfalse as ifilterfalse + + +def lovasz_grad(gt_sorted): + """ + Computes gradient of the Lovasz extension w.r.t sorted errors + See Alg. 1 in paper + """ + p = len(gt_sorted) + gts = gt_sorted.sum() + intersection = gts - gt_sorted.float().cumsum(0) + union = gts + (1 - gt_sorted).float().cumsum(0) + jaccard = 1. - intersection / union + if p > 1: # cover 1-pixel case + jaccard[1:p] = jaccard[1:p] - jaccard[0:-1] + return jaccard + + +def iou_binary(preds, labels, EMPTY=1., ignore=None, per_image=True): + """ + IoU for foreground class + binary: 1 foreground, 0 background + """ + if not per_image: + preds, labels = (preds,), (labels,) + ious = [] + for pred, label in zip(preds, labels): + intersection = ((label == 1) & (pred == 1)).sum() + union = ((label == 1) | ((pred == 1) & (label != ignore))).sum() + if not union: + iou = EMPTY + else: + iou = float(intersection) / float(union) + ious.append(iou) + iou = mean(ious) # mean accross images if per_image + return 100 * iou + + +def iou(preds, labels, C, EMPTY=1., ignore=None, per_image=False): + """ + Array of IoU for each (non ignored) class + """ + if not per_image: + preds, labels = (preds,), (labels,) + ious = [] + for pred, label in zip(preds, labels): + iou = [] + for i in range(C): + if i != ignore: # The ignored label is sometimes among predicted classes (ENet - CityScapes) + intersection = ((label == i) & (pred == i)).sum() + union = ((label == i) | ((pred == i) & (label != ignore))).sum() + if not union: + iou.append(EMPTY) + else: + iou.append(float(intersection) / float(union)) + ious.append(iou) + ious = [mean(iou) for iou in zip(*ious)] # mean accross images if per_image + return 100 * np.array(ious) + + +# --------------------------- BINARY LOSSES --------------------------- + + +def lovasz_hinge(logits, labels, per_image=True, ignore=None): + """ + Binary Lovasz hinge loss + logits: [B, H, W] Variable, logits at each pixel (between -\infty and +\infty) + labels: [B, H, W] Tensor, binary ground truth masks (0 or 1) + per_image: compute the loss per image instead of per batch + ignore: void class id + """ + if per_image: + loss = mean(lovasz_hinge_flat(*flatten_binary_scores(log.unsqueeze(0), lab.unsqueeze(0), ignore)) + for log, lab in zip(logits, labels)) + else: + loss = lovasz_hinge_flat(*flatten_binary_scores(logits, labels, ignore)) + return loss + + +def lovasz_hinge_flat(logits, labels): + """ + Binary Lovasz hinge loss + logits: [P] Variable, logits at each prediction (between -\infty and +\infty) + labels: [P] Tensor, binary ground truth labels (0 or 1) + ignore: label to ignore + """ + if len(labels) == 0: + # only void pixels, the gradients should be 0 + return logits.sum() * 0. + signs = 2. * labels.float() - 1. + errors = (1. - logits * Variable(signs)) + errors_sorted, perm = torch.sort(errors, dim=0, descending=True) + perm = perm.data + gt_sorted = labels[perm] + grad = lovasz_grad(gt_sorted) + loss = torch.dot(F.relu(errors_sorted), Variable(grad)) + return loss + + +def flatten_binary_scores(scores, labels, ignore=None): + """ + Flattens predictions in the batch (binary case) + Remove labels equal to 'ignore' + """ + scores = scores.view(-1) + labels = labels.view(-1) + if ignore is None: + return scores, labels + valid = (labels != ignore) + vscores = scores[valid] + vlabels = labels[valid] + return vscores, vlabels + + +class StableBCELoss(torch.nn.modules.Module): + def __init__(self): + super(StableBCELoss, self).__init__() + + def forward(self, input, target): + neg_abs = - input.abs() + loss = input.clamp(min=0) - input * target + (1 + neg_abs.exp()).log() + return loss.mean() + + +def binary_xloss(logits, labels, ignore=None): + """ + Binary Cross entropy loss + logits: [B, H, W] Variable, logits at each pixel (between -\infty and +\infty) + labels: [B, H, W] Tensor, binary ground truth masks (0 or 1) + ignore: void class id + """ + logits, labels = flatten_binary_scores(logits, labels, ignore) + loss = StableBCELoss()(logits, Variable(labels.float())) + return loss + + +# --------------------------- MULTICLASS LOSSES --------------------------- + + +def lovasz_softmax(probas, labels, classes='present', per_image=False, ignore=255, weighted=None): + """ + Multi-class Lovasz-Softmax loss + probas: [B, C, H, W] Variable, class probabilities at each prediction (between 0 and 1). + Interpreted as binary (sigmoid) output with outputs of size [B, H, W]. + labels: [B, H, W] Tensor, ground truth labels (between 0 and C - 1) + classes: 'all' for all, 'present' for classes present in labels, or a list of classes to average. + per_image: compute the loss per image instead of per batch + ignore: void class labels + """ + if per_image: + loss = mean(lovasz_softmax_flat(*flatten_probas(prob.unsqueeze(0), lab.unsqueeze(0), ignore), classes=classes, weighted=weighted) + for prob, lab in zip(probas, labels)) + else: + loss = lovasz_softmax_flat(*flatten_probas(probas, labels, ignore), classes=classes, weighted=weighted ) + return loss + + +def lovasz_softmax_flat(probas, labels, classes='present', weighted=None): + """ + Multi-class Lovasz-Softmax loss + probas: [P, C] Variable, class probabilities at each prediction (between 0 and 1) + labels: [P] Tensor, ground truth labels (between 0 and C - 1) + classes: 'all' for all, 'present' for classes present in labels, or a list of classes to average. + """ + if probas.numel() == 0: + # only void pixels, the gradients should be 0 + return probas * 0. + C = probas.size(1) + losses = [] + class_to_sum = list(range(C)) if classes in ['all', 'present'] else classes + for c in class_to_sum: + fg = (labels == c).float() # foreground for class c + if (classes is 'present' and fg.sum() == 0): + continue + if C == 1: + if len(classes) > 1: + raise ValueError('Sigmoid output possible only with 1 class') + class_pred = probas[:, 0] + else: + class_pred = probas[:, c] + errors = (Variable(fg) - class_pred).abs() + errors_sorted, perm = torch.sort(errors, 0, descending=True) + perm = perm.data + fg_sorted = fg[perm] + if weighted is not None: + losses.append(weighted[c]*torch.dot(errors_sorted, Variable(lovasz_grad(fg_sorted)))) + else: + losses.append(torch.dot(errors_sorted, Variable(lovasz_grad(fg_sorted)))) + return mean(losses) + + +def flatten_probas(probas, labels, ignore=None): + """ + Flattens predictions in the batch + """ + if probas.dim() == 3: + # assumes output of a sigmoid layer + B, H, W = probas.size() + probas = probas.view(B, 1, H, W) + B, C, H, W = probas.size() + probas = probas.permute(0, 2, 3, 1).contiguous().view(-1, C) # B * H * W, C = P, C + labels = labels.view(-1) + if ignore is None: + return probas, labels + valid = (labels != ignore) + # vprobas = probas[valid.nonzero().squeeze()] + vprobas = probas[torch.nonzero(valid, as_tuple =False).squeeze()] + vlabels = labels[valid] + return vprobas, vlabels + + +def xloss(logits, labels, ignore=None): + """ + Cross entropy loss + """ + return F.cross_entropy(logits, Variable(labels), ignore_index=255) + + +# --------------------------- HELPER FUNCTIONS --------------------------- +def isnan(x): + return x != x + + +def mean(l, ignore_nan=False, empty=0): + """ + nanmean compatible with generators. + """ + l = iter(l) + if ignore_nan: + l = ifilterfalse(isnan, l) + try: + n = 1 + acc = next(l) + except StopIteration: + if empty == 'raise': + raise ValueError('Empty mean') + return empty + for n, v in enumerate(l, 2): + acc += v + if n == 1: + return acc + return acc / n + +# --------------------------- Class --------------------------- +class LovaszSoftmax(nn.Module): + def __init__(self, per_image=False, ignore_index=255, weighted=None): + super(LovaszSoftmax, self).__init__() + self.lovasz_softmax = lovasz_softmax + self.per_image = per_image + self.ignore_index=ignore_index + self.weighted = weighted + + def forward(self, pred, label): + pred = F.softmax(pred, dim=1) + return self.lovasz_softmax(pred, label, per_image=self.per_image, ignore=self.ignore_index, weighted=self.weighted)