From 5289e49284f74859aea48b7c9b96eef07bcb753e Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 09:48:25 +0800
Subject: [PATCH 01/14] [CodeCamp2023-472] Add parameter save_begin

---
 docs/en/tutorials/hook.md                | 11 ++++++++++-
 docs/zh_cn/tutorials/hook.md             | 11 ++++++++++-
 mmengine/hooks/checkpoint_hook.py        | 12 ++++++++++++
 tests/test_hooks/test_checkpoint_hook.py | 22 +++++++++++++++++++++-
 4 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/docs/en/tutorials/hook.md b/docs/en/tutorials/hook.md
index 912f7502b8..c450b93133 100644
--- a/docs/en/tutorials/hook.md
+++ b/docs/en/tutorials/hook.md
@@ -71,10 +71,11 @@ runner.train()
 - Save the best checkpoints
 - Specify the path to save the checkpoints
 - Make checkpoints for publish
+- Control the epoch number or iteration number at which checkpoint saving begins
 
 For more features, please read the [CheckpointHook API documentation](mmengine.hooks.CheckpointHook).
 
-The four features mentioned above are described below.
+The six features mentioned above are described below.
 
 - Save checkpoints by interval, and support saving them by epoch or iteration
 
@@ -129,6 +130,14 @@ The four features mentioned above are described below.
   default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=1, save_best='accuracy', rule='less', published_keys=['meta', 'state_dict']))
   ```
 
+- Control the epoch number or iteration number at which checkpoint saving begins
+
+  If you want to set the number of epochs or iterations to control the start of saving weights, you can set the `save_begin` parameter, defaults to 1, which means saving checkpoints from the beginning of training. For example, if you train for a total of 10 epochs, and `save_begin` is set to 6, then the checkpoints for epochs 6, 7, 8, 9, and 10 will be saved. If `interval=2`, only save checkpoints for epochs 6, 8 and 10.
+
+  ```python
+  default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=6))
+  ```
+
 [LoggerHook](mmengine.hooks.LoggerHook) collects logs from different components of `Runner` and write them to terminal, JSON file, tensorboard and wandb .etc.
 
 If we want to output (or save) the logs every 20 iterations, we can set the `interval` parameter and configure it as follows.
diff --git a/docs/zh_cn/tutorials/hook.md b/docs/zh_cn/tutorials/hook.md
index 63e6380477..a8e9ee636c 100644
--- a/docs/zh_cn/tutorials/hook.md
+++ b/docs/zh_cn/tutorials/hook.md
@@ -72,10 +72,11 @@ runner.train()
 - 保存最优权重
 - 指定保存权重的路径
 - 制作发布用的权重
+- 设置开始保存权重的 epoch 数或者 iteration 数
 
 如需了解其他功能，请阅读 [CheckpointHook API 文档](mmengine.hooks.CheckpointHook)。
 
-下面介绍上面提到的 4 个功能。
+下面介绍上面提到的 6 个功能。
 
 - 按照间隔保存权重，支持按 epoch 数或者 iteration 数保存权重
 
@@ -130,6 +131,14 @@ runner.train()
   default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=1, save_best='accuracy', rule='less', published_keys=['meta', 'state_dict']))
   ```
 
+- 设置开始保存权重的 epoch 数或者 iteration 数
+
+  如果想要设置控制开始保存权重的 epoch 数或者 iteration 数，可以设置 `save_begin` 参数，默认为1，表示从训练开始就保存权重。例如，如果总共训练 10 个 epoch，并且 `save_begin` 设置为 6，则将保存第 6、7、8、9 和 10 个 epoch 的权重。如果`interval=2`，则仅保存epoch 6、8和10的权重。
+
+  ```python
+  default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=6))
+  ```
+
 ### LoggerHook
 
 [LoggerHook](mmengine.hooks.LoggerHook) 负责收集日志并把日志输出到终端或者输出到文件、TensorBoard 等后端。
diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index 0b0f8d9a6e..1c4c0299a1 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -92,6 +92,10 @@ class CheckpointHook(Hook):
             publish model with keys in the list after training.
             Defaults to None.
             `New in version 0.7.1.`
+        save_begin (int) : Control the epoch number or iteration number
+            at which checkpoint saving begins. Defaults to 1, which means
+            saving at the beginning.
+
     Examples:
         >>> # Save best based on single metric
         >>> CheckpointHook(interval=2, by_epoch=True, save_best='acc',
@@ -139,6 +143,7 @@ def __init__(self,
                  filename_tmpl: Optional[str] = None,
                  backend_args: Optional[dict] = None,
                  published_keys: Union[str, List[str], None] = None,
+                 save_begin: int = 1,
                  **kwargs) -> None:
         self.interval = interval
         self.by_epoch = by_epoch
@@ -244,6 +249,7 @@ def __init__(self,
         self.published_keys = published_keys
 
         self.last_ckpt = None
+        self.save_begin = save_begin
 
     def before_train(self, runner) -> None:
         """Finish all operations, related to checkpoint.
@@ -325,6 +331,9 @@ def after_train_epoch(self, runner) -> None:
         if not self.by_epoch:
             return
 
+        if runner.epoch + 1 < self.save_begin:
+            return
+
         # save checkpoint for following cases:
         # 1. every ``self.interval`` epochs
         # 2. reach the last epoch of training
@@ -642,6 +651,9 @@ def after_train_iter(self,
         if self.by_epoch:
             return
 
+        if runner.iter + 1 < self.save_begin:
+            return
+
         # save checkpoint for following cases:
         # 1. every ``self.interval`` iterations
         # 2. reach the last iteration of training
diff --git a/tests/test_hooks/test_checkpoint_hook.py b/tests/test_hooks/test_checkpoint_hook.py
index e4e982721d..7d1813615b 100644
--- a/tests/test_hooks/test_checkpoint_hook.py
+++ b/tests/test_hooks/test_checkpoint_hook.py
@@ -622,7 +622,7 @@ def test_with_runner(self, training_type):
             self.assertEqual(best_ckpt['meta']['epoch'], 0)
             self.assertEqual(best_ckpt['meta']['iter'], 5)
 
-        # test save published keys
+        # Test save published keys
         cfg = copy.deepcopy(common_cfg)
         cfg.default_hooks.checkpoint.published_keys = ['meta', 'state_dict']
         runner = self.build_runner(cfg)
@@ -632,3 +632,23 @@ def test_with_runner(self, training_type):
             any(re.findall(r'-[\d\w]{8}\.pth', file) for file in ckpt_files))
 
         self.clear_work_dir()
+
+        # Test save_begin with interval=2
+        cfg = copy.deepcopy(common_cfg)
+        cfg.default_hooks.checkpoint.interval = 2
+        cfg.default_hooks.checkpoint.save_begin = 6
+        runner = self.build_runner(cfg)
+        runner.train()
+        for i in range(6):
+            self.assertFalse(
+                osp.isfile(osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+        for i in range(6, 11):
+            if i % 2:
+                self.assertFalse(
+                    osp.isfile(
+                        osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+            else:
+                self.assertTrue(
+                    osp.isfile(
+                        osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+        self.clear_work_dir()

From 8030023cfc16d7cc360bfb039fc03c740e285dd0 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 11:11:42 +0800
Subject: [PATCH 02/14] Update docs/zh_cn/tutorials/hook.md

Co-authored-by: Mashiro <57566630+HAOCHENYE@users.noreply.github.com>
---
 docs/zh_cn/tutorials/hook.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/zh_cn/tutorials/hook.md b/docs/zh_cn/tutorials/hook.md
index a8e9ee636c..14bf922a95 100644
--- a/docs/zh_cn/tutorials/hook.md
+++ b/docs/zh_cn/tutorials/hook.md
@@ -133,7 +133,7 @@ runner.train()
 
 - 设置开始保存权重的 epoch 数或者 iteration 数
 
-  如果想要设置控制开始保存权重的 epoch 数或者 iteration 数，可以设置 `save_begin` 参数，默认为1，表示从训练开始就保存权重。例如，如果总共训练 10 个 epoch，并且 `save_begin` 设置为 6，则将保存第 6、7、8、9 和 10 个 epoch 的权重。如果`interval=2`，则仅保存epoch 6、8和10的权重。
+  如果想要设置控制开始保存权重的 epoch 数或者 iteration 数，可以设置 `save_begin` 参数，默认为 1，表示从训练开始就保存权重。例如，如果总共训练 10 个 epoch，并且 `save_begin` 设置为 6，则将保存第 6、7、8、9 和 10 个 epoch 的权重。如果 `interval=2`，则仅保存第 6、8 和 10 个 epoch 的权重。
 
   ```python
   default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=6))

From c54944b76ee9393db9dc96aff1aff8c84d39f109 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 11:11:49 +0800
Subject: [PATCH 03/14] Update tests/test_hooks/test_checkpoint_hook.py

Co-authored-by: Mashiro <57566630+HAOCHENYE@users.noreply.github.com>
---
 tests/test_hooks/test_checkpoint_hook.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/test_hooks/test_checkpoint_hook.py b/tests/test_hooks/test_checkpoint_hook.py
index 7d1813615b..b702bae875 100644
--- a/tests/test_hooks/test_checkpoint_hook.py
+++ b/tests/test_hooks/test_checkpoint_hook.py
@@ -643,7 +643,7 @@ def test_with_runner(self, training_type):
             self.assertFalse(
                 osp.isfile(osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
         for i in range(6, 11):
-            if i % 2:
+            if i % 2 == 1:
                 self.assertFalse(
                     osp.isfile(
                         osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))

From eeaa117cbd4f3fdb8f89c631d6778ee0d29418ed Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 15:30:11 +0800
Subject: [PATCH 04/14] update control range of save_begin

---
 docs/en/tutorials/hook.md                |  4 +--
 docs/zh_cn/tutorials/hook.md             |  4 +--
 mmengine/hooks/checkpoint_hook.py        | 12 ++++---
 mmengine/hooks/hook.py                   | 12 ++++---
 tests/test_hooks/test_checkpoint_hook.py | 44 +++++++++++++++++++++---
 5 files changed, 59 insertions(+), 17 deletions(-)

diff --git a/docs/en/tutorials/hook.md b/docs/en/tutorials/hook.md
index c450b93133..ac969bf984 100644
--- a/docs/en/tutorials/hook.md
+++ b/docs/en/tutorials/hook.md
@@ -132,10 +132,10 @@ The six features mentioned above are described below.
 
 - Control the epoch number or iteration number at which checkpoint saving begins
 
-  If you want to set the number of epochs or iterations to control the start of saving weights, you can set the `save_begin` parameter, defaults to 1, which means saving checkpoints from the beginning of training. For example, if you train for a total of 10 epochs, and `save_begin` is set to 6, then the checkpoints for epochs 6, 7, 8, 9, and 10 will be saved. If `interval=2`, only save checkpoints for epochs 6, 8 and 10.
+  If you want to set the number of epochs or iterations to control the start of saving weights, you can set the `save_begin` parameter, defaults to 0, which means saving checkpoints from the beginning of training. For example, if you train for a total of 10 epochs, and `save_begin` is set to 5, then the checkpoints for epochs 5, 6, 7, 8, 9, and 10 will be saved. If `interval=2`, only save checkpoints for epochs 5, 7 and 9.
 
   ```python
-  default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=6))
+  default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=5))
   ```
 
 [LoggerHook](mmengine.hooks.LoggerHook) collects logs from different components of `Runner` and write them to terminal, JSON file, tensorboard and wandb .etc.
diff --git a/docs/zh_cn/tutorials/hook.md b/docs/zh_cn/tutorials/hook.md
index 14bf922a95..36f931446d 100644
--- a/docs/zh_cn/tutorials/hook.md
+++ b/docs/zh_cn/tutorials/hook.md
@@ -133,10 +133,10 @@ runner.train()
 
 - 设置开始保存权重的 epoch 数或者 iteration 数
 
-  如果想要设置控制开始保存权重的 epoch 数或者 iteration 数，可以设置 `save_begin` 参数，默认为 1，表示从训练开始就保存权重。例如，如果总共训练 10 个 epoch，并且 `save_begin` 设置为 6，则将保存第 6、7、8、9 和 10 个 epoch 的权重。如果 `interval=2`，则仅保存第 6、8 和 10 个 epoch 的权重。
+  如果想要设置控制开始保存权重的 epoch 数或者 iteration 数，可以设置 `save_begin` 参数，默认为 0，表示从训练开始就保存权重。例如，如果总共训练 10 个 epoch，并且 `save_begin` 设置为 5，则将保存第 5、6、7、8、9 和 10 个 epoch 的权重。如果 `interval=2`，则仅保存第 5、7 和 9 个 epoch 的权重。
 
   ```python
-  default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=6))
+  default_hooks = dict(checkpoint=dict(type='CheckpointHook', interval=2, save_begin=5))
   ```
 
 ### LoggerHook
diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index 1c4c0299a1..655bb73765 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -93,7 +93,7 @@ class CheckpointHook(Hook):
             Defaults to None.
             `New in version 0.7.1.`
         save_begin (int) : Control the epoch number or iteration number
-            at which checkpoint saving begins. Defaults to 1, which means
+            at which checkpoint saving begins. Defaults to 0, which means
             saving at the beginning.
 
     Examples:
@@ -143,7 +143,7 @@ def __init__(self,
                  filename_tmpl: Optional[str] = None,
                  backend_args: Optional[dict] = None,
                  published_keys: Union[str, List[str], None] = None,
-                 save_begin: int = 1,
+                 save_begin: int = 0,
                  **kwargs) -> None:
         self.interval = interval
         self.by_epoch = by_epoch
@@ -335,9 +335,9 @@ def after_train_epoch(self, runner) -> None:
             return
 
         # save checkpoint for following cases:
-        # 1. every ``self.interval`` epochs
+        # 1. every ``self.interval`` epochs which start at ``self.save_begin``
         # 2. reach the last epoch of training
-        if self.every_n_epochs(runner, self.interval) or (
+        if self.every_n_epochs(runner, self.interval, self.save_begin) or (
                 self.save_last and self.is_last_train_epoch(runner)):
             runner.logger.info(
                 f'Saving checkpoint at {runner.epoch + 1} epochs')
@@ -656,8 +656,10 @@ def after_train_iter(self,
 
         # save checkpoint for following cases:
         # 1. every ``self.interval`` iterations
+        #       which start at ``self.save_begin``
         # 2. reach the last iteration of training
-        if self.every_n_train_iters(runner, self.interval) or \
+        if self.every_n_train_iters(runner, self.interval,
+                                    self.save_begin) or \
                 (self.save_last and
                  self.is_last_train_iter(runner)):
             runner.logger.info(
diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index 941eb86537..5ab723d2fc 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -335,18 +335,20 @@ def _after_iter(self,
             mode (str): Current mode of runner. Defaults to 'train'.
         """
 
-    def every_n_epochs(self, runner, n: int) -> bool:
+    def every_n_epochs(self, runner, n: int, st: int = 0) -> bool:
         """Test whether current epoch can be evenly divided by n.
 
         Args:
             runner (Runner): The runner of the training, validation or testing
                 process.
             n (int): Whether current epoch can be evenly divided by n.
+            st(int): The parameter of save_begin, controlling the
+                epoch number at which checkpoint saving begins.
 
         Returns:
             bool: Whether current epoch can be evenly divided by n.
         """
-        return (runner.epoch + 1) % n == 0 if n > 0 else False
+        return (runner.epoch + 1 - st) % n == 0 if n > 0 else False
 
     def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
         """Test whether current inner iteration can be evenly divided by n.
@@ -363,19 +365,21 @@ def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
         """
         return (batch_idx + 1) % n == 0 if n > 0 else False
 
-    def every_n_train_iters(self, runner, n: int) -> bool:
+    def every_n_train_iters(self, runner, n: int, st: int = 0) -> bool:
         """Test whether current training iteration can be evenly divided by n.
 
         Args:
             runner (Runner): The runner of the training, validation or testing
                 process.
             n (int): Whether current iteration can be evenly divided by n.
+            st(int): The parameter of save_begin, controlling the
+                iteration number at which checkpoint saving begins.
 
         Returns:
             bool: Return True if the current iteration can be evenly divided
             by n, otherwise False.
         """
-        return (runner.iter + 1) % n == 0 if n > 0 else False
+        return (runner.iter + 1 - st) % n == 0 if n > 0 else False
 
     def end_of_epoch(self, dataloader, batch_idx: int) -> bool:
         """Check whether the current iteration reaches the last iteration of
diff --git a/tests/test_hooks/test_checkpoint_hook.py b/tests/test_hooks/test_checkpoint_hook.py
index b702bae875..d731a42b76 100644
--- a/tests/test_hooks/test_checkpoint_hook.py
+++ b/tests/test_hooks/test_checkpoint_hook.py
@@ -633,16 +633,34 @@ def test_with_runner(self, training_type):
 
         self.clear_work_dir()
 
-        # Test save_begin with interval=2
+        # Test save_begin with interval=2, save_begin=5
         cfg = copy.deepcopy(common_cfg)
         cfg.default_hooks.checkpoint.interval = 2
-        cfg.default_hooks.checkpoint.save_begin = 6
+        cfg.default_hooks.checkpoint.save_begin = 5
         runner = self.build_runner(cfg)
         runner.train()
-        for i in range(6):
+
+        for i in range(5):
             self.assertFalse(
                 osp.isfile(osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
-        for i in range(6, 11):
+        for i in range(5, 11):
+            if (i - 5) % 2 == 1:
+                self.assertFalse(
+                    osp.isfile(
+                        osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+            else:
+                self.assertTrue(
+                    osp.isfile(
+                        osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+        self.clear_work_dir()
+
+        # Test save_begin with interval=2, save_begin=0
+        cfg = copy.deepcopy(common_cfg)
+        cfg.default_hooks.checkpoint.interval = 2
+        runner = self.build_runner(cfg)
+        runner.train()
+
+        for i in range(1, 11):
             if i % 2 == 1:
                 self.assertFalse(
                     osp.isfile(
@@ -652,3 +670,21 @@ def test_with_runner(self, training_type):
                     osp.isfile(
                         osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
         self.clear_work_dir()
+
+        # Test save_begin with interval=2, save_begin=1
+        cfg = copy.deepcopy(common_cfg)
+        cfg.default_hooks.checkpoint.interval = 2
+        cfg.default_hooks.checkpoint.save_begin = 1
+        runner = self.build_runner(cfg)
+        runner.train()
+
+        for i in range(1, 11):
+            if i % 2 == 1:
+                self.assertTrue(
+                    osp.isfile(
+                        osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+            else:
+                self.assertFalse(
+                    osp.isfile(
+                        osp.join(cfg.work_dir, f'{training_type}_{i}.pth')))
+        self.clear_work_dir()

From 3e04557a4753eb4bb26990556aea5355bf328049 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:16:45 +0800
Subject: [PATCH 05/14] Update mmengine/hooks/hook.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
---
 mmengine/hooks/hook.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index 5ab723d2fc..38d4bf91cf 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -335,7 +335,7 @@ def _after_iter(self,
             mode (str): Current mode of runner. Defaults to 'train'.
         """
 
-    def every_n_epochs(self, runner, n: int, st: int = 0) -> bool:
+    def every_n_epochs(self, runner, n: int, start: int = 0) -> bool:
         """Test whether current epoch can be evenly divided by n.
 
         Args:

From dc0ba7ca741d6ee9f96a58877884a71ec0b0fd54 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:16:52 +0800
Subject: [PATCH 06/14] Update mmengine/hooks/checkpoint_hook.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
---
 mmengine/hooks/checkpoint_hook.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index 655bb73765..5ccf472959 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -92,9 +92,10 @@ class CheckpointHook(Hook):
             publish model with keys in the list after training.
             Defaults to None.
             `New in version 0.7.1.`
-        save_begin (int) : Control the epoch number or iteration number
+        save_begin (int): Control the epoch number or iteration number
             at which checkpoint saving begins. Defaults to 0, which means
             saving at the beginning.
+            `New in version 0.8.3.`
 
     Examples:
         >>> # Save best based on single metric

From 20cc16cdf611ac3b101f4b9d4c46797b15d1455c Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:17:07 +0800
Subject: [PATCH 07/14] Update mmengine/hooks/checkpoint_hook.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
---
 mmengine/hooks/checkpoint_hook.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index 5ccf472959..2c3f9387fe 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -250,6 +250,8 @@ def __init__(self,
         self.published_keys = published_keys
 
         self.last_ckpt = None
+        if save_begin < 0:
+            raise ValueError('save_begin should not less than 0, but got {save_begin}')
         self.save_begin = save_begin
 
     def before_train(self, runner) -> None:

From 24e5a400cbaa357919759d5c229e68147ea4e126 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:17:29 +0800
Subject: [PATCH 08/14] Update mmengine/hooks/hook.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
---
 mmengine/hooks/hook.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index 38d4bf91cf..97657a0544 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -342,8 +342,8 @@ def every_n_epochs(self, runner, n: int, start: int = 0) -> bool:
             runner (Runner): The runner of the training, validation or testing
                 process.
             n (int): Whether current epoch can be evenly divided by n.
-            st(int): The parameter of save_begin, controlling the
-                epoch number at which checkpoint saving begins.
+            start (int): Starting from `start` to check the logic for every n epochs.
+                Defaults to 0.
 
         Returns:
             bool: Whether current epoch can be evenly divided by n.

From 7132692c5587b1d8162cadbabbaa30583446e6df Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:17:50 +0800
Subject: [PATCH 09/14] Update mmengine/hooks/hook.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
---
 mmengine/hooks/hook.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index 97657a0544..ec33403531 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -348,7 +348,8 @@ def every_n_epochs(self, runner, n: int, start: int = 0) -> bool:
         Returns:
             bool: Whether current epoch can be evenly divided by n.
         """
-        return (runner.epoch + 1 - st) % n == 0 if n > 0 else False
+        dividend = runner.epoch + 1 - start
+        return dividend % n == 0 if dividend >=0 and n > 0 else False
 
     def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
         """Test whether current inner iteration can be evenly divided by n.

From fa3aeac1fdb3133ced008fe92edc5763b9265b87 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:25:40 +0800
Subject: [PATCH 10/14] fix code mention above and do pre-commit check again

---
 mmengine/hooks/checkpoint_hook.py |  6 ++----
 mmengine/hooks/hook.py            | 15 ++++++++-------
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index 2c3f9387fe..b7f6cc0c4a 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -251,7 +251,8 @@ def __init__(self,
 
         self.last_ckpt = None
         if save_begin < 0:
-            raise ValueError('save_begin should not less than 0, but got {save_begin}')
+            raise ValueError(
+                'save_begin should not less than 0, but got {save_begin}')
         self.save_begin = save_begin
 
     def before_train(self, runner) -> None:
@@ -654,9 +655,6 @@ def after_train_iter(self,
         if self.by_epoch:
             return
 
-        if runner.iter + 1 < self.save_begin:
-            return
-
         # save checkpoint for following cases:
         # 1. every ``self.interval`` iterations
         #       which start at ``self.save_begin``
diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index ec33403531..4e1c4ce8bd 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -342,14 +342,14 @@ def every_n_epochs(self, runner, n: int, start: int = 0) -> bool:
             runner (Runner): The runner of the training, validation or testing
                 process.
             n (int): Whether current epoch can be evenly divided by n.
-            start (int): Starting from `start` to check the logic for every n epochs.
-                Defaults to 0.
+            start (int): Starting from `start` to check the logic for
+                every n epochs. Defaults to 0.
 
         Returns:
             bool: Whether current epoch can be evenly divided by n.
         """
         dividend = runner.epoch + 1 - start
-        return dividend % n == 0 if dividend >=0 and n > 0 else False
+        return dividend % n == 0 if dividend >= 0 and n > 0 else False
 
     def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
         """Test whether current inner iteration can be evenly divided by n.
@@ -366,21 +366,22 @@ def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
         """
         return (batch_idx + 1) % n == 0 if n > 0 else False
 
-    def every_n_train_iters(self, runner, n: int, st: int = 0) -> bool:
+    def every_n_train_iters(self, runner, n: int, start: int = 0) -> bool:
         """Test whether current training iteration can be evenly divided by n.
 
         Args:
             runner (Runner): The runner of the training, validation or testing
                 process.
             n (int): Whether current iteration can be evenly divided by n.
-            st(int): The parameter of save_begin, controlling the
-                iteration number at which checkpoint saving begins.
+            start (int): Starting from `start` to check the logic for
+                every n iterations. Defaults to 0.
 
         Returns:
             bool: Return True if the current iteration can be evenly divided
             by n, otherwise False.
         """
-        return (runner.iter + 1 - st) % n == 0 if n > 0 else False
+        dividend = runner.iter + 1 - start
+        return dividend % n == 0 if dividend >= 0 and n > 0 else False
 
     def end_of_epoch(self, dataloader, batch_idx: int) -> bool:
         """Check whether the current iteration reaches the last iteration of

From 28c339ba5f347f1d199c766a404041f273939d37 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:32:54 +0800
Subject: [PATCH 11/14] Update mmengine/hooks/checkpoint_hook.py

Co-authored-by: Zaida Zhou <58739961+zhouzaida@users.noreply.github.com>
---
 mmengine/hooks/checkpoint_hook.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index b7f6cc0c4a..94082182c3 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -252,7 +252,7 @@ def __init__(self,
         self.last_ckpt = None
         if save_begin < 0:
             raise ValueError(
-                'save_begin should not less than 0, but got {save_begin}')
+                'save_begin should not be less than 0, but got {save_begin}')
         self.save_begin = save_begin
 
     def before_train(self, runner) -> None:

From 9a084d133d1b3b2a0856cfe796b55d20b7ab6dc9 Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 17:40:39 +0800
Subject: [PATCH 12/14] delete

---
 mmengine/hooks/checkpoint_hook.py | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/mmengine/hooks/checkpoint_hook.py b/mmengine/hooks/checkpoint_hook.py
index b7f6cc0c4a..03e00b0829 100644
--- a/mmengine/hooks/checkpoint_hook.py
+++ b/mmengine/hooks/checkpoint_hook.py
@@ -335,9 +335,6 @@ def after_train_epoch(self, runner) -> None:
         if not self.by_epoch:
             return
 
-        if runner.epoch + 1 < self.save_begin:
-            return
-
         # save checkpoint for following cases:
         # 1. every ``self.interval`` epochs which start at ``self.save_begin``
         # 2. reach the last epoch of training

From dc8b1adf7f7e4431ebe4ae89a1923a6830997cce Mon Sep 17 00:00:00 2001
From: KerwinKai <101576779+KerwinKai@users.noreply.github.com>
Date: Tue, 25 Jul 2023 18:05:23 +0800
Subject: [PATCH 13/14] try to fix unit test failed

---
 mmengine/hooks/hook.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index 4e1c4ce8bd..3aa18ac239 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -348,7 +348,7 @@ def every_n_epochs(self, runner, n: int, start: int = 0) -> bool:
         Returns:
             bool: Whether current epoch can be evenly divided by n.
         """
-        dividend = runner.epoch + 1 - start
+        dividend = int(runner.epoch + 1 - start)
         return dividend % n == 0 if dividend >= 0 and n > 0 else False
 
     def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
@@ -380,7 +380,7 @@ def every_n_train_iters(self, runner, n: int, start: int = 0) -> bool:
             bool: Return True if the current iteration can be evenly divided
             by n, otherwise False.
         """
-        dividend = runner.iter + 1 - start
+        dividend = int(runner.iter + 1 - start)
         return dividend % n == 0 if dividend >= 0 and n > 0 else False
 
     def end_of_epoch(self, dataloader, batch_idx: int) -> bool:

From d6256cf8c232ef6ded3a5258ea5068e96500c9ac Mon Sep 17 00:00:00 2001
From: HAOCHENYE <21724054@zju.edu.cn>
Date: Tue, 25 Jul 2023 19:05:14 +0800
Subject: [PATCH 14/14] Avoid to compare  (MagicMock) with other integers.

---
 mmengine/hooks/hook.py               | 4 ++--
 tests/test_hooks/test_logger_hook.py | 4 ++++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/mmengine/hooks/hook.py b/mmengine/hooks/hook.py
index 3aa18ac239..4e1c4ce8bd 100644
--- a/mmengine/hooks/hook.py
+++ b/mmengine/hooks/hook.py
@@ -348,7 +348,7 @@ def every_n_epochs(self, runner, n: int, start: int = 0) -> bool:
         Returns:
             bool: Whether current epoch can be evenly divided by n.
         """
-        dividend = int(runner.epoch + 1 - start)
+        dividend = runner.epoch + 1 - start
         return dividend % n == 0 if dividend >= 0 and n > 0 else False
 
     def every_n_inner_iters(self, batch_idx: int, n: int) -> bool:
@@ -380,7 +380,7 @@ def every_n_train_iters(self, runner, n: int, start: int = 0) -> bool:
             bool: Return True if the current iteration can be evenly divided
             by n, otherwise False.
         """
-        dividend = int(runner.iter + 1 - start)
+        dividend = runner.iter + 1 - start
         return dividend % n == 0 if dividend >= 0 and n > 0 else False
 
     def end_of_epoch(self, dataloader, batch_idx: int) -> bool:
diff --git a/tests/test_hooks/test_logger_hook.py b/tests/test_hooks/test_logger_hook.py
index d2670b5b4b..52b8bc1fa3 100644
--- a/tests/test_hooks/test_logger_hook.py
+++ b/tests/test_hooks/test_logger_hook.py
@@ -63,6 +63,9 @@ def test_init(self):
 
     def test_after_train_iter(self):
         # Test LoggerHook by iter.
+        # Avoid to compare `Runner.iter` (MagicMock) with other integers.
+        ori_every_n_train_iters = LoggerHook.every_n_train_iters
+        LoggerHook.every_n_train_iters = MagicMock(return_value=True)
         runner = MagicMock()
         runner.log_processor.get_log_after_iter = MagicMock(
             return_value=(dict(), 'log_str'))
@@ -112,6 +115,7 @@ def test_after_train_iter(self):
         logger_hook = LoggerHook()
         logger_hook.after_train_iter(runner, batch_idx=8)
         runner.log_processor.get_log_after_iter.assert_called()
+        LoggerHook.every_n_train_iters = ori_every_n_train_iters
 
     def test_after_val_epoch(self):
         logger_hook = LoggerHook()