diff --git a/.obsidian/app.json b/.obsidian/app.json
index a70afcf..72a38a6 100644
--- a/.obsidian/app.json
+++ b/.obsidian/app.json
@@ -1,7 +1,7 @@
 {
   "promptDelete": false,
   "newLinkFormat": "relative",
-  "attachmentFolderPath": "./assets/Diffusion Models： A Comprehensive Survey of Methods and Applications",
+  "attachmentFolderPath": "./assets/预备知识",
   "showUnsupportedFiles": false,
   "newFileLocation": "current",
   "useMarkdownLinks": true,
diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index 05ceeea..96d92b6 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -13,7 +13,7 @@
             "state": {
               "type": "markdown",
               "state": {
-                "file": "Paper/Diffusion/Diffusion Models： A Comprehensive Survey of Methods and Applications.md",
+                "file": "Study/DL/动手学深度学习/预备知识.md",
                 "mode": "source",
                 "source": false
               }
@@ -77,8 +77,7 @@
       }
     ],
     "direction": "horizontal",
-    "width": 315.5,
-    "collapsed": true
+    "width": 315.5
   },
   "right": {
     "id": "c501495747cfa761",
@@ -94,7 +93,7 @@
             "state": {
               "type": "backlink",
               "state": {
-                "file": "Paper/Diffusion/Diffusion Models： A Comprehensive Survey of Methods and Applications.md",
+                "file": "Study/DL/动手学深度学习/预备知识.md",
                 "collapseAll": false,
                 "extraContext": false,
                 "sortOrder": "alphabetical",
@@ -111,7 +110,7 @@
             "state": {
               "type": "outgoing-link",
               "state": {
-                "file": "Paper/Diffusion/Diffusion Models： A Comprehensive Survey of Methods and Applications.md",
+                "file": "Study/DL/动手学深度学习/预备知识.md",
                 "linksCollapsed": false,
                 "unlinkedCollapsed": true
               }
@@ -134,7 +133,7 @@
             "state": {
               "type": "outline",
               "state": {
-                "file": "Paper/Diffusion/Diffusion Models： A Comprehensive Survey of Methods and Applications.md"
+                "file": "Study/DL/动手学深度学习/预备知识.md"
               }
             }
           },
@@ -167,8 +166,10 @@
   },
   "active": "7006e33745a6f46e",
   "lastOpenFiles": [
-    "Paper/Untitled.md",
     "Paper/Diffusion/Diffusion Models： A Comprehensive Survey of Methods and Applications.md",
+    "Study/DL/动手学深度学习/预备知识.md",
+    "Study/DL/动手学深度学习",
+    "Paper/Untitled.md",
     "Paper/Diffusion",
     "Study/乐理",
     "Paper/CLIP/Open-Vocabulary Semantic Segmentation.md",
@@ -191,7 +192,6 @@
     "Books/未命名.md",
     "Study/DL/吴恩达深度学习课程/Other.md",
     "Study/DL",
-    "Study",
     "Books/Java Guide/基础语法.md",
     "Books/Java并发编程/Java并发编程.md",
     "Books/从零开始深入学习Spring/IoC.md",
@@ -201,7 +201,6 @@
     "Books/代码随想录/().md",
     "_notion-like-tables/table-id-ncD19n.md",
     "未命名.md",
-    "Basic/未命名.md",
-    "Excalidraw/Drawing 2023-02-19 16.06.15.excalidraw.md"
+    "Basic/未命名.md"
   ]
 }
\ No newline at end of file
diff --git a/Study/DL/动手学深度学习/预备知识.md b/Study/DL/动手学深度学习/预备知识.md
new file mode 100644
index 0000000..5fa12e4
--- /dev/null
+++ b/Study/DL/动手学深度学习/预备知识.md
@@ -0,0 +1,4 @@
+# 矩阵计算
+| $y$ | $a$ | $au$ | sum(x) |  |
+| ---- | ---- | ---- | ---- | ---- |
+| $\frac{\partial y}{\partial \mathbf x}$ | $0^T$ | $a \frac{\partial u}{\partial \mathbf x}$ | $1^T$ |  |