Fitting of X-ray scattering data using evolutionary algorithms

A method for estimating parameters of a material, comprising the steps of:

• i) obtaining experimental x-ray scattering data which is indicative of parameter values for the material;
• ii) estimating a first vector of parameters for the material;
• iii) generating additional parameter vectors from said first vector parameter;
• iv) simulating x-ray scattering data for each of said parameter vectors and calculating an error value for each parameter vector based upon a comparison of the experimental and simulated scattering data;
• v) generating a test vector which is based upon random mutation of at least one of said parameter vectors;
• vi) comparing an error value for said test vector with the error value for a designated one of said parameter vectors;
• and
• vii) selecting the vector having the lower error value as a new estimate for the parameters of the material.

A computer-readable medium containing a program which executes the steps of:

• calculating simulated x-ray scattering data for an estimated model of a material;
• comparing the simulated x-ray scattering data with experimental data to generate an error value;
• modifying the model by means of an evolutionary algorithm to reduce said error value;
• and
• reporting the parameter values which characterize the modified model as an estimate of the parameter values for the material.

A computer readable medium containing a program which executes the steps of:

• generating a plurality of parameter vectors for a material;
• simulating x-ray scattering data for each of said parameter vectors and calculating an error value for each parameter vector based upon a comparison of experimental data and said simulated scattering data;
• generating a test vector which is based upon random mutation of at least one of said parameter vectors;
• comparing an error value for said test vector with the error value for a designated one of said parameter vectors;
• and
• selecting the vector having the lower error value as a new estimate for the parameters of the material.