fix Progression to actually do what we claim in the doc (missing -1 in
the formula: confusion between num_points and num_intervals)

Mesh/1D_Mesh.cpp

-// $Id: 1D_Mesh.cpp,v 1.46 2006-01-06 00:34:25 geuzaine Exp $
+// $Id: 1D_Mesh.cpp,v 1.47 2006-01-19 02:26:21 geuzaine Exp $
 //
 // Copyright (C) 1997-2006 C. Geuzaine, J.-F. Remacle
 //
@@ -59,7 +59,8 @@ double F_Transfini(double t)
   d = sqrt(der.Pos.X * der.Pos.X + der.Pos.Y * der.Pos.Y +
            der.Pos.Z * der.Pos.Z);
 
-  if(THEC->dpar[0] == 0.0 || THEC->dpar[0] == 1.0) {
+  if(THEC->dpar[0] <= 0.0 || THEC->dpar[0] == 1.0) {
+    // dpar[0] < 0 should never happen
     val = d * (double)THEC->ipar[0] / THEC->l;
   }
   else {
@@ -70,10 +71,7 @@ double F_Transfini(double t)
 	r = THEC->dpar[0];
       else
 	r = 1. / THEC->dpar[0];
-      if(r == 1.)
-        a = THEC->l / (double)THEC->ipar[0];
-      else
-        a = THEC->l * (r - 1.) / (pow(r, THEC->ipar[0]) - 1.);
+      a = THEC->l * (r - 1.) / (pow(r, THEC->ipar[0] - 1.) - 1.);
       i = (int)(log(t * THEC->l / a * (r - 1.) + 1.) / log(r));
       val = d / (a * pow(r, (double)i));
       break;

benchmarks/1d/progression.geo

+// the mesh nodes should match the points below
+
+Point(1) = {0,0,0,1};
+Point(2) = {1,0,0,1};
+Point(3) = {3,0,0,1};
+Point(4) = {7,0,0,1};
+Point(5) = {15,0,0,1};
+
+Point(6) = {0,0.2,0,1};
+Point(7) = {15,0.2,0,1};
+Line(1) = {6,7};
+Transfinite Line {1} = 5 Using Progression 2;

benchmarks/3d/periodic.geo

 // original file from benarafa@alpes.cea.fr
 
 Lc = 0.003 ;
-nb = 12;
+nb_layers = 12;
 use_prisms = 1;
 
 Point(1) = {0.,0.,0.,Lc};
@@ -46,12 +46,12 @@ Physical Line(18) = {2,3};
 Physical Surface(19) = {15};
 
 If(use_prisms)
-  Extrude Surface {15, {0.,0.,2.*R}}{Layers{nb,83,1}; Recombine; };
+  Extrude Surface {15, {0.,0.,2.*R}}{Layers{nb_layers,83,1}; Recombine; };
 EndIf
 
 If(!use_prisms)
   Extrude Surface {15, {0.,0.,2.*R}};
-  Transfinite Line {27,55,1,59,23,43,4,39,21,34,3,35,25,51,2,47} = nb Using Progression 1.;
+  Transfinite Line {27,55,1,59,23,43,4,39,21,34,3,35,25,51,2,47} = (nb_layers+1) Using Progression 1.;
   Transfinite Surface {52} = {16,14,33,37};
   Transfinite Surface {36} = {11,15,19,18};
   Transfinite Surface {44} = {13,17,24,28};