From 8d07ce21859ca7d3dd498dec8c290f901d1604cc Mon Sep 17 00:00:00 2001
From: Mingshuang Luo <37799481+luomingshuang@users.noreply.github.com>
Date: Wed, 29 Sep 2021 13:11:52 +0800
Subject: [PATCH] Update utils.py

---
 icefall/utils.py | 75 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 74 insertions(+), 1 deletion(-)

diff --git a/icefall/utils.py b/icefall/utils.py
index 23b4dd6c7..1abc77262 100644
--- a/icefall/utils.py
+++ b/icefall/utils.py
@@ -1,4 +1,5 @@
-# Copyright      2021  Xiaomi Corp.        (authors: Fangjun Kuang)
+# Copyright      2021  Xiaomi Corp.        (authors: Fangjun Kuang
+#                                                    Mingshuang Luo)
 #
 # See ../../LICENSE for clarification regarding multiple authors
 #
@@ -17,6 +18,7 @@
 
 import argparse
 import logging
+import collections
 import os
 import subprocess
 from collections import defaultdict
@@ -29,6 +31,7 @@ import k2
 import kaldialign
 import torch
 import torch.distributed as dist
+from torch.utils.tensorboard import SummaryWriter
 
 Pathlike = Union[str, Path]
 
@@ -419,3 +422,73 @@ def write_error_stats(
 
         print(f"{word}   {corr} {tot_errs} {ref_count} {hyp_count}", file=f)
     return float(tot_err_rate)
+
+
+class LossRecord(collections.defaultdict):
+    def __init__(self):
+        # Passing the type 'int' to the base-class constructor
+        # makes undefined items default to int() which is zero.
+        super(LossRecord, self).__init__(int)
+
+    def __add__(self, other: 'LossRecord') -> 'LossRecord':
+        ans = LossRecord()
+        for k, v in self.items():
+            ans[k] = v
+        for k, v in other.items():
+            ans[k] = ans[k] + v
+        return ans
+
+    def __mul__(self, alpha: float) -> 'LossRecord':
+        ans = LossRecord()
+        for k, v in self.items():
+            ans[k] = v * alpha
+        return ans
+
+    def __str__(self) -> str:
+        ans = ''
+        for k, v in self.norm_items():
+            norm_value = '%.4g' % v
+            ans += (str(k) + '=' + str(norm_value) + ', ')
+        frames = str(self['frames'])
+        ans += 'over ' + frames + ' frames.'
+        return ans
+
+    def norm_items(self) -> List[Tuple[str, float]]:
+        """
+        Returns a list of pairs, like:
+          [('ctc_loss', 0.1), ('att_loss', 0.07)]
+        """
+        num_frames = self['frames'] if 'frames' in self else 1
+        ans = []
+        for k, v in self.items():
+            if k != 'frames':
+                norm_value = float(v) / num_frames
+                ans.append((k, norm_value))
+        return ans
+
+    def reduce(self, device):
+        """
+        Reduce using torch.distributed, which I believe ensures that
+        all processes get the total.
+        """
+        keys = sorted(self.keys())
+        s = torch.tensor([ float(self[k]) for k in keys ],
+                         device=device)
+        dist.all_reduce(s, op=dist.ReduceOp.SUM)
+        for k, v in zip(keys, s.cpu().tolist()):
+            self[k] = v
+
+    def write_summary(self, 
+                      tb_writer: SummaryWriter, 
+                      prefix: str, 
+                      batch_idx: int) -> None:
+        """Add logging information to a TensorBoard writer.
+        
+        Args:
+            tb_writer: a TensorBoard writer
+            prefix: a prefix for the name of the loss, e.g. "train/valid_",
+                or "train/current_"
+            batch_idx: The current batch index, used as the x-axis of the plot.
+        """
+        for k, v in self.norm_items():
+            tb_writer.add_scalar(prefix + k, v, batch_idx)