fix bugs in documentation and implementation of atom style mdpd

doc/src/read_data.txt

@@ -547,7 +547,7 @@ charge: atom-ID atom-type q x y z
 dipole: atom-ID atom-type q x y z mux muy muz
 dpd: atom-ID atom-type theta x y z
 edpd: atom-ID atom-type edpd_temp edpd_cv x y z 
-mdpd: atom-ID atom-type x y z
+mdpd: atom-ID atom-type rho x y z
 tdpd: atom-ID atom-type x y z cc1 cc2 ... ccNspecies
 electron: atom-ID atom-type q spin eradius x y z
 ellipsoid: atom-ID atom-type ellipsoidflag density x y z

src/USER-MESO/atom_vec_mdpd.cpp

@@ -43,9 +43,9 @@ AtomVecMDPD::AtomVecMDPD(LAMMPS *lmp) : AtomVec(lmp)
   size_reverse = 3 + 1; // 3 + drho
   size_border =  6 + 4; // 6 + rho + vest[3]
   size_velocity = 3;
-  size_data_atom = 5;
+  size_data_atom = 6;
   size_data_vel = 4;
-  xcol_data = 3;
+  xcol_data = 4;
 
   atom->rho_flag = 1;
   atom->vest_flag = 1;
@@ -817,7 +817,7 @@ void AtomVecMDPD::data_atom(double *coord, imageint imagetmp, char **values) {
   vest[nlocal][1] = 0.0;
   vest[nlocal][2] = 0.0;
 
-  rho[nlocal] = 0.0;
+  rho[nlocal] = atof(values[2]);
   drho[nlocal] = 0.0;
 
   atom->nlocal++;