The process of solving a problem in COMSOL Multiphysics is a hierarchy. The Study node () is the coarsest level (the top level). It contains the least amount of detail and defines a Study branch (see Branches and Subbranches in the Tree Structure).

When creating a new model, you can add any of the predefined Study and Study Step Types. At any time you can also add studies (see The Add Study Window). However you choose to add a study, a study node is added to The Model Builder including a corresponding study step (for example, Stationary in Figure 19-1), and in some cases, additional study steps. The study step represents the next level of detail.

Most study steps are used to control the form of the equations, what physics interfaces are included in the computation, and what mesh is used. A study step Settings window has a Physics and Variables Selection section where inclusion and exclusion of physics interfaces and variables can be adjusted and set. There are also Common Study Step Settings for many of the study features added to a sequence.

Study steps correspond to part of a solver configuration (solver sequence), which is the next level of detail. There are also study steps for cluster computing, for example, which correspond to part of the Job Configurations.

Solver Configurations contain nodes that define variables to solve for, the solvers and settings, and additional sequence nodes for storing the solution, for example (see Figure 19-1). The solvers also have nodes that can control the solver settings in detail. Knowing The Relationship Between Study Steps and Solver Configurations is useful to help define and edit the settings before computing a solution. Bear in mind, however, that the default solver settings defined by the study usually provide a good starting point.

Once the studies are added and defined, the simplest option to compute the solution is to right-click the Study node for a predefined study type and select Compute (). This generates the default solver configuration for the corresponding study steps and computes the solution. There are a variety of techniques you can use while Computing a Solution, including many custom adjustments.

There are different groups of feature types you can use to customize and fine tune the model. There are three classes of features that are subnodes to a Solution node. See Figure 19-1 for examples:

Some of the settings in subnodes are synchronized with the corresponding Study setting. They are unavailable by default and can only be controlled from the subnode by changing the Defined by study step setting to User defined.

There are also Study Extension Steps (Parametric Sweep and Optimization) and categories of Advanced Study Extension Steps ( Parametric, Batch, and Cluster Computing) for additional settings customization and extensions of a study.

For some modules, more settings are available with respect to Harmonic Perturbation, Prestressed Analysis, and Small-Signal Analysis.