diff --git a/test/pdegen/psb_d_pde2d.F90 b/test/pdegen/psb_d_pde2d.F90
index 4e65ad56..6f472b69 100644
--- a/test/pdegen/psb_d_pde2d.F90
+++ b/test/pdegen/psb_d_pde2d.F90
@@ -230,7 +230,7 @@ contains
       f_ => d_null_func_2d
     end if
 
-    deltah   = done/(idim+2)
+    deltah   = done/(idim+1)
     sqdeltah = deltah*deltah
     deltah2  = (2*done)* deltah
 
diff --git a/test/pdegen/psb_d_pde3d.F90 b/test/pdegen/psb_d_pde3d.F90
index 977ab77d..c9c1634b 100644
--- a/test/pdegen/psb_d_pde3d.F90
+++ b/test/pdegen/psb_d_pde3d.F90
@@ -246,7 +246,7 @@ contains
       f_ => d_null_func_3d
     end if
 
-    deltah   = done/(idim+2)
+    deltah   = done/(idim+1)
     sqdeltah = deltah*deltah
     deltah2  = (2*done)* deltah
 
diff --git a/test/pdegen/psb_s_pde2d.F90 b/test/pdegen/psb_s_pde2d.F90
index 54461e86..55902bdb 100644
--- a/test/pdegen/psb_s_pde2d.F90
+++ b/test/pdegen/psb_s_pde2d.F90
@@ -230,7 +230,7 @@ contains
       f_ => s_null_func_2d
     end if
 
-    deltah   = sone/(idim+2)
+    deltah   = sone/(idim+1)
     sqdeltah = deltah*deltah
     deltah2  = (2*sone)* deltah
 
diff --git a/test/pdegen/psb_s_pde3d.F90 b/test/pdegen/psb_s_pde3d.F90
index 5b3d76da..9b818dc7 100644
--- a/test/pdegen/psb_s_pde3d.F90
+++ b/test/pdegen/psb_s_pde3d.F90
@@ -246,7 +246,7 @@ contains
       f_ => s_null_func_3d
     end if
 
-    deltah   = sone/(idim+2)
+    deltah   = sone/(idim+1)
     sqdeltah = deltah*deltah
     deltah2  = (2*sone)* deltah