calculate the degree of gate constraints

src/Gate/Computation.hs

@@ -124,6 +124,18 @@ straightLineOperCount (MkStraightLine{..}) = final where
   coms  = map exprOperCount $ commits
   final = mconcat defs <> mconcat coms  
 
+-- | Maximum degree of a gate's constraints
+constraintDegree :: StraightLine -> Int
+constraintDegree (MkStraightLine{..}) = maxdeg where
+  ndefs = length localdefs
+  table = array (0,ndefs-1) [ (i, exprDegree lkp rhs) | MkLocalDef i _ rhs <- localdefs ]
+  lkp var = case var of
+    LocalVar i _ -> table!i
+    ProofVar v   -> case v of { PIV {} -> 0 ; _ -> 1 }
+  maxdeg = case commits of
+    [] -> 0
+    _  -> maximum (map (exprDegree lkp) commits)
+
 --------------------------------------------------------------------------------
 
 type Scope a = IntMap a

src/Gate/Vars.hs

@@ -18,7 +18,7 @@ data PlonkyVar
   = SelV   Int        -- ^ selector variable
   | ConstV Int        -- ^ constant variable
   | WireV  Int        -- ^ wire variable
-  | PIV    Int        -- ^ public input hash variable
+  | PIV    Int        -- ^ public input hash variable (technically these are constants, not variables)
   deriving (Eq,Ord,Show)
 
 instance Pretty PlonkyVar where

src/Test/Witness.hs

@@ -70,6 +70,11 @@ test_fibonacci = do
   let pubio_prg = gateProgram (PublicInputGate  )
   let const_prg = gateProgram (ConstantGate    2)
 
+  putStrLn $ "maximum degree of constraints in ArithmeticGate  = " ++ show (constraintDegree arith_prg)
+  putStrLn $ "maximum degree of constraints in PosiedonGate    = " ++ show (constraintDegree posei_prg)
+  putStrLn $ "maximum degree of constraints in PublicInputGate = " ++ show (constraintDegree pubio_prg)
+  putStrLn $ "maximum degree of constraints in ConstGate       = " ++ show (constraintDegree const_prg)
+
   let arith_evals = runStraightLine (fmap fromBase arith_row) arith_prg  
   let posei_evals = runStraightLine (fmap fromBase posei_row) posei_prg
   let const_evals = runStraightLine (fmap fromBase const_row) const_prg
@@ -92,5 +97,5 @@ test_fibonacci = do
   
 --------------------------------------------------------------------------------
 
-main :: IO
+main :: IO ()
 main = test_fibonacci