SimΠ is a PHP script that allows calculation of unit cell identity parameter [1] using orthogonalization of unit cell parameters via SVD (singular value decomposition) [2] of specific matrix. Whole process is described during calculation.


  1. L. Fábián, A. Kálmán: Acta Cryst. B 55 (1999) 1099-1108.
  2. K. Baker: "Singular Value Decomposition Tutorial", The Ohio State University (2005).