update op_add related

moonbitlang · May 30, 2024 · 718f7bb · 718f7bb
1 parent d6152e7
commit 718f7bb
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Showing 4 changed files with 23 additions and 10 deletions.
diff --git a/course12/course_en.md b/course12/course_en.md
@@ -1,5 +1,5 @@
 ---
-marp: true
+marp: false
 math: mathjax
 paginate: true
 backgroundImage: url('../pics/background_moonbit.png')
@@ -145,8 +145,9 @@ headingDivider: 1
 	  let symbol : Symbol = example() // Abstract syntax tree of the function
 	  @assertion.assert_eq(symbol.compute(input), 600.0)?
 	  // Expression of df/dx
-	  inspect(symbol.differentiate(0), content="Add(Add(Mul(Mul(Constant(5.0), Var(0)), Constant(1.0)), Mul(Add(Mul(Constant(5.0), Constant(1.0)), Mul(Constant(0.0), Var(0))), Var(0))), Constant(0.0))")?
-	  @assertion.assert_eq(symbol.differentiate(0).compute(input), 50.0)?
+	  inspect(symbol.differentiate(0), 
+	  content="Add(Add(Mul(Mul(Constant(5.0), Var(0)), Constant(1.0)), Mul(Add(Mul(Constant(5.0), Constant(1.0)), Mul(Constant(0.0), Var(0))), Var(0))), Constant(0.0))")?
+	  @assertion.assert_eq(symbol.differentiate(0).compute(input), 100.0)?
 	}
 	```
 - Here, `diff_0` is:
@@ -163,10 +164,16 @@ headingDivider: 1
 	```moonbit
 	fn Symbol::op_add_simplified(f1 : Symbol, f2 : Symbol) -> Symbol {
 	  match (f1, f2) {
-	    (Constant(0.0), a) => a // 0 + a = a
-	    (Constant(a), Constant(b)) => Constant(a * b)
-	    (a, Constant(_) as const) => const + a
-	    _ => Add(f1, f2)
+	    (Constant(0.0), a) => a
+        (Constant(a), Constant(b)) => Constant(a + b)
+        (a, Constant(_) as const) => const + a
+        (Mul(n, Var(x1)), Mul(m, Var(x2))) =>
+          if x1 == x2 {
+            Mul(m + n, Var(x1))
+          } else {
+            Add(f1, f2)
+          }
+        _ => Add(f1, f2)
     } }
   ```
 

diff --git a/course12/course_en.pdf b/course12/course_en.pdf
diff --git a/course12/lec12.mbt b/course12/lec12.mbt
@@ -19,8 +19,14 @@ fn Symbol::op_add(f1 : Symbol, f2 : Symbol) -> Symbol {
   // With simplification 以下为化简实现
   match (f1, f2) {
     (Constant(0.0), a) => a
-    (Constant(a), Constant(b)) => Constant(a * b)
+    (Constant(a), Constant(b)) => Constant(a + b)
     (a, Constant(_) as const) => const + a
+    (Mul(n, Var(x1)), Mul(m, Var(x2))) =>
+      if x1 == x2 {
+        Mul(m + n, Var(x1))
+      } else {
+        Add(f1, f2)
+      }
     _ => Add(f1, f2)
   }
 }
@@ -67,7 +73,7 @@ test "Symbolic differentiation 符号微分" {
   @assertion.assert_eq(symbol.compute(input), 600.0)?
   // Expression of df/dx 关于x的偏微分表达式树
   inspect(symbol.differentiate(0), ~content="Mul(Constant(5.0), Var(0))")?
-  @assertion.assert_eq(symbol.differentiate(0).compute(input), 50.0)?
+  @assertion.assert_eq(symbol.differentiate(0).compute(input), 100.0)?
   @assertion.assert_eq(symbol.differentiate(1).compute(input), 1.0)?
 }
 

diff --git a/course12/lec12_script.md b/course12/lec12_script.md
@@ -1,4 +1,4 @@
-# 现代编程思想：案例：语法解析器
+# 现代编程思想：案例：自动微分
 
 大家好，欢迎来到由IDEA研究院基础软件中心为大家带来的现代编程思想公开课。今天我们继续案例学习，主题是自动微分。我会避开一些复杂的数学概念。