Validation of codes for cores in hexagonal and other geometries and optimal use of information

In connection with the transfer of technologies between countries of the formerly divided world, the word {open_quotes}validation{close_quotes} frequently used. Let us try to analyze what it really denotes the clerical, physical, and mathematical points of view. For our special case, it denotes a transfer of calculations between various geometries and sets of measurements. The standard way is a more or less automatic comparison in tables. The purpose of such a procedure is to have an optimal description of experiments. Mathematically, validation denotes a minimum of the least-squares functional for measurement and theory. Limitations are equations, which should be fulfilled; doubts are imprecisely defined situations or coefficients in the equations. It was shown that such a variational problem could be solved either directly (through derivative of measurement over the searched parameters) or by introducing a generalized Lagrange multiplier method in which equations are included in functionals.