diff --git a/postprocessor.py b/postprocessor.py
index b50426d..1848111 100644
--- a/postprocessor.py
+++ b/postprocessor.py
@@ -1329,7 +1329,7 @@ class PostProcessor(HDF5Container):
         # Thermal support
         GPy, GPx = np.gradient(Pz, dy, dx, edge_order=2)
         gradPr = (xx * GPx + yy * GPy) / rr
-        fP = gradPr / rho
+        fP = -gradPr / rho
 
         # Gravitational field
         e2 = (1.0 / 512) ** 2
@@ -1342,13 +1342,12 @@ class PostProcessor(HDF5Container):
         # Forces at the center of filaments
         Rdisk_center = Rdisk[i_center, j_center]
         gr_center = gdisk[i_center, j_center]
-        fP_center = fP[i_center, j_center]
         dvr_center = dvr[i_center, j_center]
 
         # Forces for the filaments equilibrium
         Rfil = Rdisk - Rdisk_center
         gfil = gdisk - gr_center
-        fPfil = fP - fP_center
+        fPfil = fP
         dvr_fil = dvr - dvr_center
 
         return {"gfil": gfil, "Rfil": Rfil, "fPfil": fPfil, "dvr": dvr_fil}