Merge pull request #343 from Consensys/340-add-model-for-bit_decompos…

…ition-example

feat: add model for `bit_decomposition` example

.pre-commit-config.yaml

@@ -11,7 +11,7 @@ repos:
     rev: v1.0.0-rc.1
     hooks:
       - id: go-test-mod
-        args: [ --run=Test_ ]
+        args: [ --run=Test_Basic ]
   - repo: https://github.com/golangci/golangci-lint
     rev: v1.57.1
     hooks:

cmd/testgen/main.go

@@ -72,6 +72,7 @@ type Model struct {
 }
 
 var models []Model = []Model{
+	{"bit_decomposition", bitDecompositionModel},
 	{"memory", memoryModel},
 	{"word_sorting", wordSortingModel},
 }
@@ -272,6 +273,48 @@ func wordSortingModel(schema sc.Schema, trace tr.Trace) bool {
 	return true
 }
 
+func bitDecompositionModel(schema sc.Schema, trace tr.Trace) bool {
+	TWO_1 := fr.NewElement(2)
+	TWO_2 := fr.NewElement(4)
+	TWO_3 := fr.NewElement(8)
+	TWO_4 := fr.NewElement(16)
+	//
+	NIBBLE := findColumn(0, "NIBBLE", schema, trace).Data()
+	BIT_0 := findColumn(0, "BIT_0", schema, trace).Data()
+	BIT_1 := findColumn(0, "BIT_1", schema, trace).Data()
+	BIT_2 := findColumn(0, "BIT_2", schema, trace).Data()
+	BIT_3 := findColumn(0, "BIT_3", schema, trace).Data()
+	//
+	for i := uint(0); i < NIBBLE.Len(); i++ {
+		NIBBLE_i := NIBBLE.Get(i)
+		BIT_0_i := BIT_0.Get(i)
+		BIT_1_i := BIT_1.Get(i)
+		BIT_2_i := BIT_2.Get(i)
+		BIT_3_i := BIT_3.Get(i)
+		// Check types
+		t_NIBBLE := NIBBLE_i.Cmp(&TWO_4) < 0
+		t_BIT_0 := BIT_0_i.Cmp(&TWO_1) < 0
+		t_BIT_1 := BIT_1_i.Cmp(&TWO_1) < 0
+		t_BIT_2 := BIT_2_i.Cmp(&TWO_1) < 0
+		t_BIT_3 := BIT_3_i.Cmp(&TWO_1) < 0
+		// Check type constraints
+		if !(t_NIBBLE && t_BIT_0 && t_BIT_1 && t_BIT_2 && t_BIT_3) {
+			return false
+		}
+		//
+		b1 := mul(BIT_1_i, TWO_1)
+		b2 := mul(BIT_2_i, TWO_2)
+		b3 := mul(BIT_3_i, TWO_3)
+		sum := add(add(add(b3, b2), b1), BIT_0_i)
+		// Check decomposition matches
+		if NIBBLE_i.Cmp(&sum) != 0 {
+			return false
+		}
+	}
+	// Success
+	return true
+}
+
 // ============================================================================
 // Helpers
 // ============================================================================

testdata/bit_decomposition.auto.accepts

@@ -0,0 +1,3 @@
+{"NIBBLE": [0, 0], "BIT_0": [0, 0], "BIT_1": [0, 0], "BIT_2": [0, 0], "BIT_3": [0, 0]}
+{"NIBBLE": [0, 1], "BIT_0": [0, 1], "BIT_1": [0, 0], "BIT_2": [0, 0], "BIT_3": [0, 0]}
+{"NIBBLE": [0, 2], "BIT_0": [0, 0], "BIT_1": [0, 1], "BIT_2": [0, 0], "BIT_3": [0, 0]}