# Function reference

## Types

 Dimension Symbol defining an iteration space. ConditionalDimension Symbol defining a non-convex iteration sub-space derived from a `parent` SubDimension Symbol defining a convex iteration sub-space derived from a `parent` Grid A cartesian grid that encapsulates a computational domain over which CustomTopology The CustomTopology class provides a mechanism to describe parametric domain SubDomain Base class to define Grid subdomains. Constant Symbol representing a constant, scalar value in symbolic equations. Function Tensor symbol representing a discrete function in symbolic equations. TimeFunction Tensor symbol representing a discrete function in symbolic equations. VectorFunction Vector valued space varying Function as a rank 1 tensor of Function. VectorTimeFunction Time varying VectorFunction. TensorFunction Tensor valued Function represented as a Matrix. TensorTimeFunction Time varying TensorFunction. SparseFunction Tensor symbol representing a sparse array in symbolic equations. SparseTimeFunction Tensor symbol representing a space- and time-varying sparse array in symbolic PrecomputedSparseFunction Tensor symbol representing a sparse array in symbolic equations; unlike PrecomputedSparseTimeFunction Tensor symbol representing a space- and time-varying sparse array in symbolic

## Operator

 Operator Generate, JIT-compile and run C code starting from an ordered sequence Eq An equal relation between two objects, the left-hand side and the

## Finite differences

 div Divergence of the input Function. grad Gradient of the input Function. curl Curl of the input Function. Only supported for VectorFunction diag Creates a diagonal tensor with func on its diagonal. laplace Laplacian of the input Function. Derivative An unevaluated Derivative, which carries metadata (Dimensions, Coefficient Prepare custom coefficients to pass to a Substitutions object. Substitutions Devito class to convert Coefficient objects into replacent rules

## Utilities

 smooth Smooth a Function through simple moving average. initialize_function Initialize a Function with the given `data`. `data` mmin Retrieve the minimum. mmax Retrieve the maximum. sum Compute the sum of the Function data over specified dimensions. norm Compute the norm of a Function.