Added add_intermediate and add_secure_intermediate to eval API.

crates/prover/src/constraint_framework/expr.rs

@@ -772,34 +772,35 @@ pub struct ExprEvaluator {
     pub cur_var_index: usize,
     pub constraints: Vec<ExtExpr>,
     pub logup: FormalLogupAtRow,
-    pub intermediates: Vec<(String, ExtExpr)>,
+    pub intermediates: Vec<(String, BaseExpr)>,
+    pub secure_intermediates: Vec<(String, ExtExpr)>,
 }
 
 impl ExprEvaluator {
-    #[allow(dead_code)]
     pub fn new(log_size: u32, has_partial_sum: bool) -> Self {
         Self {
             cur_var_index: Default::default(),
             constraints: Default::default(),
             logup: FormalLogupAtRow::new(INTERACTION_TRACE_IDX, has_partial_sum, log_size),
             intermediates: vec![],
+            secure_intermediates: vec![],
         }
     }
 
-    pub fn add_intermediate(&mut self, expr: ExtExpr) -> ExtExpr {
-        let name = format!("intermediate{}", self.intermediates.len());
-        let intermediate = ExtExpr::Param(name.clone());
-        self.intermediates.push((name, expr));
-        intermediate
-    }
-
     pub fn format_constraints(&self) -> String {
         let lets_string = self
             .intermediates
             .iter()
             .map(|(name, expr)| format!("let {} = {};", name, expr.simplify_and_format()))
             .collect::<Vec<String>>()
-            .join("\n");
+            .join("\n\n");
+
+        let secure_lets_string = self
+            .secure_intermediates
+            .iter()
+            .map(|(name, expr)| format!("let {} = {};", name, expr.simplify_and_format()))
+            .collect::<Vec<String>>()
+            .join("\n\n");
 
         let constraints_str = self
             .constraints
@@ -809,7 +810,12 @@ impl ExprEvaluator {
             .collect::<Vec<String>>()
             .join("\n\n");
 
-        lets_string + "\n\n" + &constraints_str
+        [lets_string, secure_lets_string, constraints_str]
+            .iter()
+            .filter(|x| !x.is_empty())
+            .cloned()
+            .collect::<Vec<_>>()
+            .join("\n\n")
     }
 }
 
@@ -858,14 +864,35 @@ impl EvalAtRow for ExprEvaluator {
                      multiplicity,
                      values,
                  }| {
-                    let intermediate = self.add_intermediate(combine_formal(*relation, values));
+                    let intermediate =
+                        self.add_secure_intermediate(combine_formal(*relation, values));
                     Fraction::new(multiplicity.clone(), intermediate)
                 },
             )
             .collect();
         self.write_logup_frac(fracs.into_iter().sum());
     }
 
+    fn add_intermediate(&mut self, expr: Self::F) -> Self::F {
+        let name = format!(
+            "intermediate{}",
+            self.intermediates.len() + self.secure_intermediates.len()
+        );
+        let intermediate = BaseExpr::Param(name.clone());
+        self.intermediates.push((name, expr));
+        intermediate
+    }
+
+    fn add_secure_intermediate(&mut self, expr: Self::EF) -> Self::EF {
+        let name = format!(
+            "intermediate{}",
+            self.intermediates.len() + self.secure_intermediates.len()
+        );
+        let intermediate = ExtExpr::Param(name.clone());
+        self.secure_intermediates.push((name, expr));
+        intermediate
+    }
+
     super::logup_proxy!();
 }
 
@@ -1031,21 +1058,22 @@ mod tests {
     fn test_format_expr() {
         let test_struct = TestStruct {};
         let eval = test_struct.evaluate(ExprEvaluator::new(16, false));
-        let expected = "let intermediate0 = (TestRelation_alpha0) * (col_1_0[0]) \
+        let expected = "let intermediate0 = (col_1_1[0]) * (col_1_2[0]);
+
+\
+        let intermediate1 = (TestRelation_alpha0) * (col_1_0[0]) \
             + (TestRelation_alpha1) * (col_1_1[0]) \
             + (TestRelation_alpha2) * (col_1_2[0]) \
             - (TestRelation_z);
 
 \
-        let constraint_0 = \
-            (((col_1_0[0]) * (col_1_1[0])) * (col_1_2[0])) * (1 / (col_1_0[0] + col_1_1[0]));
+        let constraint_0 = ((col_1_0[0]) * (intermediate0)) * (1 / (col_1_0[0] + col_1_1[0]));
 
 \
         let constraint_1 = (SecureCol(col_2_4[0], col_2_6[0], col_2_8[0], col_2_10[0]) \
             - (SecureCol(col_2_5[-1], col_2_7[-1], col_2_9[-1], col_2_11[-1]) \
-                - ((total_sum) * (col_0_3[0])))\
-            ) \
-            * (intermediate0) \
+                - ((total_sum) * (col_0_3[0])))) \
+            * (intermediate1) \
             - (1);"
             .to_string();
 
@@ -1066,9 +1094,8 @@ mod tests {
             let x0 = eval.next_trace_mask();
             let x1 = eval.next_trace_mask();
             let x2 = eval.next_trace_mask();
-            eval.add_constraint(
-                x0.clone() * x1.clone() * x2.clone() * (x0.clone() + x1.clone()).inverse(),
-            );
+            let intermediate = eval.add_intermediate(x1.clone() * x2.clone());
+            eval.add_constraint(x0.clone() * intermediate * (x0.clone() + x1.clone()).inverse());
             eval.add_to_relation(&[RelationEntry::new(
                 &TestRelation::dummy(),
                 E::EF::one(),

crates/prover/src/constraint_framework/mod.rs

@@ -111,6 +111,18 @@ pub trait EvalAtRow {
     where
         Self::EF: Mul<G, Output = Self::EF> + From<G>;
 
+    /// Adds an intermediate value to the component and returns its value.
+    /// Does nothing by default.
+    fn add_intermediate(&mut self, val: Self::F) -> Self::F {
+        val
+    }
+
+    /// Adds a secure intermediate value to the component and returns its value.
+    /// Does nothing by default.
+    fn add_secure_intermediate(&mut self, val: Self::EF) -> Self::EF {
+        val
+    }
+
     /// Combines 4 base field values into a single extension field value.
     fn combine_ef(values: [Self::F; SECURE_EXTENSION_DEGREE]) -> Self::EF;
 

crates/prover/src/examples/state_machine/mod.rs

@@ -357,6 +357,7 @@ mod tests {
         let expected = "let intermediate0 = (StateMachineElements_alpha0) * (col_1_0[0]) \
             + (StateMachineElements_alpha1) * (col_1_1[0]) \
             - (StateMachineElements_z);
+
 \
         let intermediate1 = (StateMachineElements_alpha0) * (col_1_0[0] + 1) \
             + (StateMachineElements_alpha1) * (col_1_1[0]) \