Sorted DTW algorithm and path extraction without decomposing into mod…

…ules

fluid/example/dtw/matrix-update.fld

@@ -35,20 +35,29 @@ let feq Infty Infty = True;
 let minAndPrev (i, j) im1 jm1 ijm1 = 
     let minim = fminimal [im1, jm1, ijm1] in
         if feq minim im1 then
-            ((i - 1, j), minim)
+            ((i, j + 1), minim)
         else
             if feq minim jm1 then
-                ((i, j - 1), minim)
-            else ((i - 1, j - 1), minim);
-
-let localMinUpdate seq1 seq2 matrix (i, j) = 
+                ((i + 1, j ), minim)
+            else ((i, j), minim);
+let extractPath indmatrix (i, j) =
+    let traverser (n,m) matrix accum =
+        if and (n == 1) (m == 1)
+        then accum
+        else
+            traverser (matrix!(n,m)) matrix ((n - 1,m - 1) : accum)
+    in traverser (i,j) indmatrix Nil;        
+let localMinUpdate seq1 seq2 (costmatrix, indmatrix) (i, j) = 
       let iEntr = nth (i - 1) seq1;
           jEntr = nth (j - 1) seq2;
           dist = (iEntr - jEntr) * (iEntr - jEntr);
-          im1 = matrix!(i , j + 1);
-          jm1 = matrix!(i + 1, j);
-          im1jm1 = matrix!(i , j );
-          ((prei,prej), minim) = minAndPrev (i + 1, j + 1) im1 jm1 im1jm1;
+          im1 = costmatrix!(i , j + 1);
+          jm1 = costmatrix!(i + 1, j);
+          im1jm1 = costmatrix!(i , j );
+          (prev, minim) = minAndPrev (i, j) im1 jm1 im1jm1;
           newVal = fadd (FNum dist) minim
-      in matrixUpdate matrix (i + 1,j + 1) newVal
-in foldl (localMinUpdate [3,1,2,2,1] [2,0,0,3,3,1,0]) (costMatrixInit 6 8 2) (nextIndices 5 7 2)  
+      in (matrixUpdate costmatrix (i + 1,j + 1) newVal, matrixUpdate indmatrix (i + 1,j + 1) prev)
+in
+    let (finished, indices) = foldl (localMinUpdate [3,1,2,2,1] [2,0,0,3,3,1,0]) (costMatrixInit 6 8 2, [| 0 | (i,j) in (6, 8) |]) (nextIndices 5 7 2)
+    in
+        (finished, extractPath indices (6,8))