diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index f10c8da..3f17da5 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -36,13 +36,13 @@
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-                "mode": "source",
+                "file": "04. Programming/Machine Learning.md",
+                "mode": "preview",
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@@ -114,7 +114,7 @@
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@@ -139,7 +139,7 @@
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+                "file": "04. Programming/Machine Learning.md"
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@@ -190,8 +190,12 @@
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+    "04. Programming/Machine Learning.md",
+    "00. Inbox/01. TODO.md",
+    "04. Programming/Python/argparse.ArgumentParser.md",
     "05. 資料收集/皮質醇.md",
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     "05. 資料收集/讀書筆記/20201201 - 學習如何學習.md",
@@ -211,18 +215,14 @@
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     "04. Programming/Python/matplotlib.md",
-    "04. Programming/Machine Learning.md",
     "05. 資料收集/核心肌群訓練.md",
     "05. 資料收集/Capture One.md",
     "05. 資料收集/AI.md",
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     "01. 個人/01. Daily/2023-05-11(週四).md",
     "01. 個人/01. Daily/2023-05-12(週五).md",
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diff --git a/04. Programming/Machine Learning.md b/04. Programming/Machine Learning.md
index 87eec92..698eed6 100644
--- a/04. Programming/Machine Learning.md	
+++ b/04. Programming/Machine Learning.md	
@@ -3,9 +3,9 @@
 
 |  問題類型   | 啟動函數 |                損失函數                |
 |:-----------:|:--------:|:--------------------------------------:|
-|  二元分類   | sigmoid  |   binary_crossentropy（二元交叉熵）    |
-|  多元分類   | softmax  | categorical_crossentropy（分類交叉熵） |
+|  二元分類   | sigmoid  |   binary_crossentropy（二元交叉熵）    | 
+|  單標籤多元分類   | softmax  | [[categorical_crossentropy]]（分類交叉熵）<br> sparse_categorical_crossentropy |
 | 多標籤分類  | sigmoid  |          binary_crossentropy           |
-|  回歸求值   |   None   |            mse（均方誤差）             | 
+|  回歸求值   |   None   |            mse（均方誤差）             |
 | 回歸求0~1值 | sigmoid  |        mse或binary_crossentropy        |
 
diff --git a/04. Programming/categorical_crossentropy.md b/04. Programming/categorical_crossentropy.md
new file mode 100644
index 0000000..e7526ac
--- /dev/null
+++ b/04. Programming/categorical_crossentropy.md	
@@ -0,0 +1,2 @@
+- 僅適用於 one-hot 編碼。
+- 如果輸出不是 one-hot，而是整數標籤，也就是直接輸出 0、1、2，而不是一個array（`[0, 0, 0, 1, 0]` 之類），那就需要 sparse_categorical_crossentropy。
\ No newline at end of file