A simplex optimization method for the precise determination of symmetry-constrained lattice constants from diffractometer data

A method for the determination of a symmetry-constrained least-squares orientation matrix and unit cell is described. The method retains the simplicity of early iterative techniques since it avoids the use of cumbersome constraining equations resulting from the application of Lagrange multipliers, yet it does not require the evaluation of numerical derivatives. The straightforward nature of simplex optimization makes the algorithm extremely easy to program in Fortran, Pascal and Basic. (orig.)