Grid/TODO

================================================================
*** Hacks and bug fixes to clean up and Audits
================================================================

*  Extract/merge/set cleanup ; too many variants; rationalise and call simpler ones
*  Used #define repetitive sequences to minimise code.
*  Rewrite core tensor arithmetic support to be more systematic
*  Ensure we ET as much as possible; move unop functions into ET framework.
   - tests with expression args to all functions


* FIXME audit
* const audit

Insert/Extract
* Replace vset with a call to merge.; 
* care in Gmerge,Gextract over vset .
* extract / merge extra implementation removal      
* Optimise the extract/merge SIMD routines; Azusa??
 - I have collated into single location at least.
 - Need to use _mm_*insert/extract routines.

* Thread scaling tests Xeon, XeonPhi

** Make the Tensor types and Complex etc... play more nicely.
  - TensorRemove is a hack, come up with a long term rationalised approach to Complex vs. Scalar<Scalar<Scalar<Complex > > >
  QDP forces use of "toDouble" to get back to non tensor scalar. This role is presently taken TensorRemove, but I
  want to introduce a syntax that does not require this.

  - Reductions that contract indices on a site should always demote the tensor structure.
    norm2(), innerProduct.

  - Result of Sum(), SliceSum // spatial sums
              trace, traceIndex etc.. do not.

  - problem arises because "trace" returns Lattice<TComplex> moving everything down to Scalar,
    and then Sum and SliceSum to not remove the Scalars. This would be fixed if we 
    template specialize the scalar scalar scalar sum and SliceSum,  on the basis of being
    pure scalar.

*** Expression template engine: -- DONE

[   -- Norm2(expression) problem: introduce norm2 unary op, or Introduce conversion automatic from expression to Lattice<vobj>
* Strong test for norm2, conj and all primitive types. -- tests/Grid_simd.cc is almost there
* Implement where within expression template scheme.
* Check for missing functionality                    - partially audited against QDP++ layout

   // Unary functions
   // cos,sin, tan, acos, asin, cosh, acosh, tanh, sinh, // Scalar<vReal> only arg
   // exp, log, sqrt, fabs
   // transposeColor, transposeSpin,
   // adjColor, adjSpin,
   // copyMask.
   // localMaxAbs
   // Fourier transform equivalent.]

================================================================
*** New Functionality
================================================================

* - BinaryWriter, TextWriter etc...
  - use protocol buffers? replace xmlReader/Writer ec..
  - Binary use htonll, htonl

* CovariantShift support                             -----Use a class to store gauge field? (parallel transport?)

* Parallel io improvements
  - optional parallel MPI2 IO
  - move Plaquette and link trace checks into nersc reader from the Grid_nersc_io.cc test.

* Support for ILDG

* Support different boundary conditions (finite temp, chem. potential ... )

* Support different fermion representations? 

Actions -- coherent framework for implementing actions and their forces.

* Fermion
  - Wilson
  - Clover
  - DomainWall
  - Mobius
  - z-Mobius

Algorithms (lots of reuse/port from BFM)
* LinearOperator
* LinearSolver
* Polynomial 
* Eigen
* CG
* Pcg
* Adef2
* DeflCG
* fPcg
* MCR
* HDCG
* HMC, 
* Heatbath
* Integrators, leapfrog, omelyan, force gradient etc...
* etc..

* Gauge
  - Wilson, symanzik, iwasaki

* rb4d support for 5th dimension in Mobius.

* Flavour matrices?
* Pauli, SU subgroup, etc.. 
* su3 exponentiation & log etc.. [Jamie's code?]
* TaProj
* FFTnD ?


======================================================================================================
FUNCTIONALITY: it pleases me to keep track of things I have done (keeps me arguably sane)
======================================================================================================

* Command line args for geometry, simd, etc. layout. Is it necessary to have -- DONE
  user pass these? Is this a QCD specific?

* Stencil -- DONE
* Test infrastructure -- DONE
* Fourspin, two spin project --- DONE
* Dirac Gamma/Dirac structures ---- DONE
* Conditional execution, where etc...                -----DONE, simple test
* Integer relational support                         -----DONE
* Coordinate information, integers etc...            -----DONE
* Integer type padding/union to vector.              -----DONE 
* LatticeCoordinate[mu]                              -----DONE
* expose traceIndex, peekIndex, transposeIndex etc at the Lattice Level -- DONE
* TraceColor, TraceSpin.                             ----- DONE (traceIndex<1>,traceIndex<2>, transposeIndex<1>,transposeIndex<2>)
                                                     ----- Implement mapping between traceColour and traceSpin and traceIndex<1/2>.
* How to do U[mu] ... lorentz part of type structure or not. more like chroma if not. -- DONE

* Twospin/Fourspin/Gamma/Proj/Recon                  ----- DONE
* norm2l is a hack. figure out syntax error and make this norm2 c.f. tests/Grid_gamma.cc -- DONE

* subdirs lib, tests ??                              ----- DONE
  - lib/math        
  - lib/cartesian
  - lib/cshift
  - lib/stencil
  - lib/communicator
  - lib/algorithms
  - lib/qcd
 future
  - lib/io/   -- GridLog, GridIn, GridErr, GridDebug, GridMessage
  - lib/qcd/actions
  - lib/qcd/measurements

* Subset support, slice sums etc...                  -----DONE
  sliceSum(orthog)
  sum
  innerProduct
  norm2

* Subgrid Transferral                                -----DONE
  subBlock (coarseLattice,fineLattice)
  projectBlockBasis  
  promoteBlockBasis

* random number generation                           ----- DONE

* Broadcast, reduction tests. innerProduct, localInnerProduct --- DONE

* I/O support
* NERSC Lattice loading, plaquette test             ------- DONE single node 

* Controling std::cout                              ------- DONE

* Had to hack assignment to 1.0 in the tests/Grid_gamma test -- DONE
* Reduce implemention is poor ; need threaded reductions; OMP isn't able to do it for generic objects. -- DONE
* Bug in RNG with complex numbers ; only filling real values; need helper function -- DONE
* Conformable test in Cshift routines. -- none needed ; there is only one 
* Conformable testing in expression templates -- DONE (recursive)

* Bug in SeedFixedIntegers gave same output on each site. -- DONE
  Implement and use lattice IO to verify this.            -- cout for lattice types DONE