Commit Graph

3 Commits

Author SHA1 Message Date
François Coppens
b2b4756b53 Problem solved. Problems was caused by reading the inverse matrix S_inv the same way as the matrix S, but apparently what has been stored is transpose(S_inv) and not S_inv. Therefore it needs to be read transposed compared to S in order to for S*S_inv to give the Identity matrix.
TODO: Calls from C/C++ are still broken because inside the MaponiA3 algo there is compensation for the fact that Fortran sends it's arrays in column-major order. This must be resolved by  transposeing S_inv before it is passed to MaponiA3 and remove the compensations made there.
2021-02-22 15:43:27 +01:00
François Coppens
8d63dd1701 The algorithm now works for the following 4x4 example with 2 updates:
S = [1,0,1,-1; 0,1,1,0; -1,0,-1,0; 1,1,1,1]
S_inv = [1,-1,1,1; 1,0,2,1; -1,1,-2,-1; -1,0,-1,0]
u1 = [0,-2,0,0]
u2 = [0,-1,0,0]
upd_idx = [2,4]

To go from Maponi's examples where the number of updates is always equal
to the the dimension of the matrix, and the decomposition is always
diagonal, to cases with a non-diagonal decomposition and a number of
updates unequal to its size, the following changed needed to be made:

* in the calculation of the {y0k} an extra inner for-loop needs to be
  added to make it a full matrix-vector multiplication due to the fact
  that A0 is not a diagonal matrix

* in some places the use of the update-order vector p needs
  the be replaced with that of upd_idx to make sure the correct
  component of the ylk is selected and the proper rank-1 matrices are
  constructed

* when a matrix is passed from Fortran to C++ with 2D adressing, it is
  passed in colum-major order. The passed matrix needs to be transposed
  before passing to C++. Doing this inside the algorithm will break
  compatibility with called from C/C++.
2021-02-22 15:41:30 +01:00
François
48c27eb47e * Modified Maponi algo 3 so that it can be used with a number of updates
that is smaller than the size of the Slater-matrix
* Removed the Slater-matrix as an argument, since it is not used in the
  algo.
* Added a manual 4x4 example to debug MaponiA3 to work with a number of
  updates that is smaller than the size of the Slater-matrix
* Added a new Octave script to quickly check if the computes inverse is
  correct.
2021-02-22 15:34:34 +01:00