This symposium brings together mathematicians, computer scientists, chemists and physicist to address a truly multidisciplinary issue of enabling large-scale atomistically-resolved, ab initio materials modeling. Such modeling capabilities are required for understanding and rational design of materials ranging from alloys to solid electrolytes for fuel cells. There is a substantial gap in theory and computing techniques which on one hand would be able to model phenomena intrinsically requiring models with millions of atoms and on the other hand provide accuracy and insight which is today routinely achievable only for unrealistically small model systems . This is a gap between a model and a reality. To bridge it, this symposium makes brains from different research fields pull in one direction. Progress that this symposium will help accelerate will mean better computational support for the development of functional materials, with more of the development moved from time-, manpower-, and $-costly lab experimentation to in-silico design.