1. 18 Jul, 2018 2 commits
  2. 11 Dec, 2016 1 commit
  3. 08 Dec, 2016 1 commit
  4. 03 Dec, 2016 2 commits
  5. 01 Dec, 2016 3 commits
  6. 30 Nov, 2016 3 commits
    • Christoph Conrads's avatar
      Src: manually provide a matrix decomposition · 9487615b
      Christoph Conrads authored
      Preserving the symmetry fixes the out-of-memory situations [on my
      computer] with the test matrix bmwcra_1.
      9487615b
    • Christoph Conrads's avatar
      d2118ec2
    • Christoph Conrads's avatar
      Src: subspace iteration for small search spaces · 7776693d
      Christoph Conrads authored
      This commit replaces Chebyshev polynomials with inverse iteration to
      avoid accidentally wiping out a perfectly good approximate eigenvector
      (cf. commit 33c1, Nov 28, 2016).
      
      Inverse iteration updates only the lower part of the spectrum quite well
      so the idea is to compute eigenpairs with Rayleigh-Ritz early and then
      to improve eigenpairs selectively. The two major problems tackled in
      this commit are missing eigenpairs and the forward error; the backward
      error is usually not a problem, e.g., on vanbody, the backward error of
      all eigenpairs after one inverse iteration is below the single-precision
      epsilon 1.1*10^-7. We ensure finding all desired eigenpairs by applying
      shift-and-invert to eigenpairs with eigenvalues above the cutoff. A
      large forward error can have two causes:
      - a large condition number, or
      - the use of shifted matrices causing a large residual.
      Hence, to reduce the forward error we must use inverse iteration without
      shifts, especially after executing shift-and-invert.
      
      With this commit, we find all 1265 eigenpairs below the cutoff 20 on
      vanbody in 993 seconds (1780 seconds CPU time). This is a significant
      improvement over the previous record with commit 3dce, July 27, 2016
      (1063 seconds wall-clock time, 1890 second CPU time). Additionally, the
      search space dimension decreased from 2064 to 1453.
      7776693d
  7. 28 Nov, 2016 6 commits
  8. 27 Nov, 2016 6 commits
  9. 26 Nov, 2016 7 commits
  10. 25 Nov, 2016 1 commit
  11. 23 Nov, 2016 2 commits
  12. 22 Nov, 2016 6 commits