diff --git a/.gitignore b/.gitignore
index d743ee06..44e063b9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -88,11 +88,17 @@ Thumbs.db
 ###################
 build*/*
 
+# bootstrap #
+#############
+*.tar.bz2*
+
 # IDE related files #
 #####################
 *.xcodeproj/*
 build.sh
 .vscode
+.ctags
+tags
 
 # Eigen source #
 ################
diff --git a/bootstrap.sh b/bootstrap.sh
index ac27ef25..1510e3a1 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -1,11 +1,16 @@
 #!/usr/bin/env bash
 
-EIGEN_URL='http://bitbucket.org/eigen/eigen/get/3.3.3.tar.bz2'
+EIGEN_SRC='3.3.3.tar.bz2'
+EIGEN_URL="http://bitbucket.org/eigen/eigen/get/${EIGEN_SRC}"
 
-echo "-- deploying Eigen source..."
-wget ${EIGEN_URL} --no-check-certificate
-./scripts/update_eigen.sh `basename ${EIGEN_URL}`
-#rm `basename ${EIGEN_URL}`
+if [ -f ${EIGEN_SRC} ]; then
+  echo "-- skip deploying Eigen source..."
+else
+  echo "-- deploying Eigen source..."
+  wget ${EIGEN_URL} --no-check-certificate
+  ./scripts/update_eigen.sh `basename ${EIGEN_URL}`
+  #rm `basename ${EIGEN_URL}`
+fi
 
 echo '-- generating Make.inc files...'
 ./scripts/filelist
diff --git a/tests/lanczos/Test_dwf_block_lanczos.cc b/tests/lanczos/Test_dwf_block_lanczos.cc
new file mode 100644
index 00000000..da721efa
--- /dev/null
+++ b/tests/lanczos/Test_dwf_block_lanczos.cc
@@ -0,0 +1,107 @@
+    /*************************************************************************************
+
+    Grid physics library, www.github.com/paboyle/Grid 
+
+    Source file: ./tests/Test_dwf_lanczos.cc
+
+    Copyright (C) 2015
+
+Author: Peter Boyle <paboyle@ph.ed.ac.uk>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License along
+    with this program; if not, write to the Free Software Foundation, Inc.,
+    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+    See the full license in the file "LICENSE" in the top level distribution directory
+    *************************************************************************************/
+    /*  END LEGAL */
+#include <Grid/Grid.h>
+
+using namespace std;
+using namespace Grid;
+using namespace Grid::QCD;
+
+typedef typename GparityDomainWallFermionR::FermionField FermionField;
+
+RealD AllZero(RealD x){ return 0.;}
+
+int main (int argc, char ** argv)
+{
+  Grid_init(&argc,&argv);
+
+  const int Ls=8;
+
+  GridCartesian         * UGrid   = SpaceTimeGrid::makeFourDimGrid(GridDefaultLatt(), GridDefaultSimd(Nd,vComplex::Nsimd()),GridDefaultMpi());
+  GridRedBlackCartesian * UrbGrid = SpaceTimeGrid::makeFourDimRedBlackGrid(UGrid);
+  GridCartesian         * FGrid   = SpaceTimeGrid::makeFiveDimGrid(Ls,UGrid);
+  GridRedBlackCartesian * FrbGrid = SpaceTimeGrid::makeFiveDimRedBlackGrid(Ls,UGrid);
+  printf("UGrid=%p UrbGrid=%p FGrid=%p FrbGrid=%p\n",UGrid,UrbGrid,FGrid,FrbGrid);
+
+  std::vector<int> seeds4({1,2,3,4});
+  std::vector<int> seeds5({5,6,7,8});
+  GridParallelRNG          RNG5(FGrid);  RNG5.SeedFixedIntegers(seeds5);
+  GridParallelRNG          RNG4(UGrid);  RNG4.SeedFixedIntegers(seeds4);
+  GridParallelRNG          RNG5rb(FrbGrid);  RNG5.SeedFixedIntegers(seeds5);
+
+  LatticeGaugeField Umu(UGrid); 
+  SU3::HotConfiguration(RNG4, Umu);
+
+  std::vector<LatticeColourMatrix> U(4,UGrid);
+  for(int mu=0;mu<Nd;mu++){
+    U[mu] = PeekIndex<LorentzIndex>(Umu,mu);
+  }
+  
+  RealD mass=0.01;
+  RealD M5=1.8;
+  RealD mob_b=1.5;
+//  DomainWallFermionR Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5);
+  GparityMobiusFermionD ::ImplParams params;
+  std::vector<int> twists({1,1,1,0});
+  params.twists = twists;
+  GparityMobiusFermionR  Ddwf(Umu,*FGrid,*FrbGrid,*UGrid,*UrbGrid,mass,M5,mob_b,mob_b-1.,params);
+
+//  MdagMLinearOperator<DomainWallFermionR,LatticeFermion> HermOp(Ddwf);
+//  SchurDiagTwoOperator<DomainWallFermionR,LatticeFermion> HermOp(Ddwf);
+  SchurDiagTwoOperator<GparityMobiusFermionR,FermionField> HermOp(Ddwf);
+//  SchurDiagMooeeOperator<DomainWallFermionR,LatticeFermion> HermOp(Ddwf);
+
+  const int Nstop = 30;
+  const int Nk = 40;
+  const int Np = 40;
+  const int Nm = Nk+Np;
+  const int MaxIt= 10000;
+  RealD resid = 1.0e-8;
+
+  std::vector<double> Coeffs { 0.,-1.};
+  Polynomial<FermionField> PolyX(Coeffs);
+  Chebyshev<FermionField> Cheb(0.2,5.,11);
+//  ChebyshevLanczos<LatticeFermion> Cheb(9.,1.,0.,20);
+//  Cheb.csv(std::cout);
+//  exit(-24);
+  ImplicitlyRestartedLanczos<FermionField> IRL(HermOp,Cheb,Nstop,Nk,Nm,resid,MaxIt);
+
+  
+  std::vector<RealD>          eval(Nm);
+  FermionField    src(FrbGrid); 
+  gaussian(RNG5rb,src);
+  std::vector<FermionField> evec(Nm,FrbGrid);
+  for(int i=0;i<1;i++){
+    std::cout << GridLogMessage <<i<<" / "<< Nm<< " grid pointer "<<evec[i]._grid<<std::endl;
+  };
+
+  int Nconv;
+  //IRL.calc(eval,evec,src,Nconv);
+
+
+  Grid_finalize();
+}
diff --git a/tests/lanczos/Test_wilson_lanczos.cc b/tests/lanczos/Test_wilson_lanczos.cc
index e8549234..bf8bb8f1 100644
--- a/tests/lanczos/Test_wilson_lanczos.cc
+++ b/tests/lanczos/Test_wilson_lanczos.cc
@@ -58,7 +58,7 @@ int main(int argc, char** argv) {
   GridParallelRNG RNG4(UGrid);
   RNG4.SeedFixedIntegers(seeds4);
   GridParallelRNG RNG5rb(FrbGrid);
-  RNG5.SeedFixedIntegers(seeds5);
+  RNG5.SeedFixedIntegers(seeds5); // ypj [note] Does it mean RNG5rb? RNG5rb is never used.
 
   LatticeGaugeField Umu(UGrid);
   SU3::HotConfiguration(RNG4, Umu);