Computational physics can be stated as the study and the implementation of the numerical analysis for solving problems in physics for which there is the existence of a quantitative theory. Some time ago, computational physics was used as a application of modern computers in the field of science but now, it has become a subset of computational science.
It is basically an intermediate branch between the experimental physics and the theoretical physics which helps in supplementing both theory and experiment. In simple words, it is using computers for solving the problems of physics, for explaining the theories of physics along with its stimulations. It makes the life of computational physicists easier.
In the field of physics, various theories based on the mathematical models seem to predict the behavior of the systems. Unfortunately, many a times, solving the mathematical model for predicting a useful outcome is not always possible.
This occurs when the solution is complicated or does not have closed-form expression. In these cases, a numerical representation is needed. Computational physics deals with such numerical approximations. A computer is used for writing the solution in simple mathematical algorithm along with computing a solution with respective error.
There is more often than not a debate about the status of computers in physics. Many scientists regard the simulation of computers as mere computer experiments while some treat it as theoretical physics. The main purpose of using computers in physics is because the calculations get easier and the stored data is secure.
Computational physics helps in broadening and deepening of the understanding of physics in the human mind and also increases the range of calculations that can be performed mathematically.
Some of the software used in this field is MATHEMATICA, MAPLE, MATLAB etc. NAG, 4 LINPACK, 5 ODEPACK, 6 are some of the libraries that are used for performing all the real numerical work.
Computational physics is used in a wide area of physics like astrophysics, lattice field theory, fluid mechanics, plasma physics, weather prediction, soft condensed matter, hyper velocity impact physics etc. For example, computational solid state physics used the density functional theory for calculating the properties of solids in a method similar to the one used by the chemists for studying the molecules.
Problems of physics are not very easy to solve owing to various mathematical reasons but computational physics make it easy to solve. The problems that cannot be solve using computers are the ones involving chaos which renders any solution meaningless.