Loss of precision corrected!

--- a/src/spectralLib.f95
+++ b/src/spectralLib.f95
@@ -167,7 +167,7 @@ contains
                 nn=j-N-1
             end if
             ! diagonal
-            D(j)=(ii*nn*2*PI/L)**order
+            D(j)=dble(ii*nn*2*PI/L)**order
         end do