Bench auxiliaries (#86)

* Number of auxiliaries

* Fixed typo

crates/bellpepper-core/src/constraint_system.rs

@@ -135,7 +135,7 @@ pub trait ConstraintSystem<Scalar: PrimeField>: Sized + Send {
         false
     }
 
-    /// Extend concatenates thew  `other` constraint systems to the receiver, modifying the receiver, whose
+    /// Extend concatenates the  `other` constraint systems to the receiver, modifying the receiver, whose
     /// inputs, allocated variables, and constraints will precede those of the `other` constraint system.
     /// The primary use case for this is parallel synthesis of circuits which can be decomposed into
     /// entirely independent sub-circuits. Each can be synthesized in its own thread, then the

crates/bellpepper/src/util_cs/bench_cs.rs

@@ -24,6 +24,10 @@ impl<Scalar: PrimeField> BenchCS<Scalar> {
         self.a
     }
 
+    pub fn num_auxiliaries(&self) -> usize {
+        self.aux
+    }
+
     pub fn num_inputs(&self) -> usize {
         self.inputs
     }