- Function File:
`DiffusionRate`=**diffusion***(*`Alpha`,`Sigma`) Creates an object to represent the diffusion rate of a stochastic differential equation (SDE).

`DiffusionRate`(t, X_t) = diag(X_t.^Alpha(t)) * V(t)dX_t = DriftRate(t, X_t)dt +`DiffusionRate`(t, X_t)dW_t.- (X_t) is an NVARS-dimensional process;
- (W_t) is an NBROWNS-dimensional Wiener process.

- Variable:
`Alpha`An NVARS-by-1 vector or a function. As a function,`Alpha`returns an NVARS-by-1 vector and has either exactly one input (time:`Alpha`(t)) or exactly two inputs (time and space:`Alpha`(t, X_t)). - Variable:
`Sigma`An NVARS-by-NBROWNS matrix or a function. As a function,`Sigma`returns an NVARS-by-NBROWNS matrix and has either exactly one input (time:`Sigma`(t)) or exactly two inputs (time and space:`Sigma`(t, X_t)).

**See also:**drift.

Package: financial