Apply Laplacian to negative frequencies correctly.

diff --git a/src/ofc/generators/onetep/Laplacian.scala b/src/ofc/generators/onetep/Laplacian.scala
index e70a16517d7d93d0b81e62a2bd4a28071c1c89e6..46c6632a66475c097524a78dcb8c095ace924005 100644 (file)
--- a/src/ofc/generators/onetep/Laplacian.scala
+++ b/src/ofc/generators/onetep/Laplacian.scala
@@ -21,6 +21,16 @@ class Laplacian(op: Field)  extends Field {
       // Construct loops
       val loops = for(dim <- 0 to 2) yield new ForLoop(indices(dim), 1, getSize(dim))
 
+      val frequencies = for(dim <- 0 to 2) yield {
+        val index = indices(dim)
+        val frequency = new DeclaredVarSymbol[IntType]("freq_"+(dim+1))
+        val halfWidth = getSize(dim)/2 + 1;
+        context.addDeclaration(frequency)
+        loops(dim) += new AssignStatement(frequency, 
+          new ConditionalValue[IntType](index |>| halfWidth, index - getSize(dim) - 1, index - 1))
+        frequency
+      }
+
       // Nest loops and add outer to context
       for(dim <- 1 to 2) loops(dim) += loops(dim-1)
       context += loops(2)
@@ -35,7 +45,7 @@ class Laplacian(op: Field)  extends Field {
         var component : Expression[FloatType] = new FloatLiteral(0.0)
         for(vec <- 0 to 2) {
           val vector = OnetepTypes.FFTBoxInfo.public % OnetepTypes.FFTBoxInfo.latticeReciprocal(vec)
-          component = component + vector % OnetepTypes.Point.coord(dim) * new Conversion[IntType, FloatType](indices(vec) - 1)
+          component = component + vector % OnetepTypes.Point.coord(dim) * new Conversion[IntType, FloatType](frequencies(vec))
         }
         loops(0) += new AssignStatement(reciprocalVector(dim), component)
       }