Lots of changes

lib/Petzval/Optimization.hs

@@ -0,0 +1,33 @@
+{-# LANGUAGE NoMonomorphismRestriction #-}
+module Petzval.Optimization where
+
+import Control.Lens
+import Control.Lens.Unsound (adjoin)
+import Numeric.AD.Mode
+import Numeric.AD.Mode.Reverse.Double
+import Petzval.Optics
+import Petzval.Types
+
+-- | A set of modifiable parts of a lens system, expressed as a traversal.
+-- The recommended way of generating a variable set is with the following construction:
+-- @
+-- vars = ix 1 . roc `adjoin` ix 2 . thickness
+-- @
+type VariableSet = forall mat a. Traversal' [Element mat a] a
+type AdMode s = ReverseDouble s
+
+extractVars :: VariableSet -> [Element mat a] -> [a]
+extractVars vars system = system ^. partsOf vars
+
+setVars :: VariableSet -> [Element mat a] -> [a] -> [Element mat a]
+setVars vars system vals = system & partsOf vars .~ vals
+
+gradientAt :: VariableSet -- ^ The set of independent variables
+           -> (forall a. Calcuable a => [Element mat a] -> a) -- ^ merit function
+           -> [Element mat Double] -- ^ The system
+           -> (Double, [Double]) -- ^ The gradient
+gradientAt vars merit system =  grad' (merit . setVars vars (system & each.liftFp %~ auto)) (extractVars vars system)
+           
+
+
+-- instances