$VersionNumber (Built-in Mathematica Symbol)

$VersionNumber is a real number which gives the current Mathematica kernel version number, and increases in successive versions.

Overview of Higher-Order ODEs (Mathematica Tutorial)

The general form of an ODE with order n is As in the case of second-order ODEs, such an ODE can be classified as linear or nonlinear. The general form of a linear ODE of ...

ControllableModelQ (Built-in Mathematica Symbol)

ControllableModelQ[ss] yields True if the StateSpaceModel object ss is controllable, and False otherwise.

Get (Built-in Mathematica Symbol)

<< name reads in a file, evaluating each expression in it, and returning the last one.

MatrixQ (Built-in Mathematica Symbol)

MatrixQ[expr] gives True if expr is a list of lists or a two-dimensional SparseArray object that can represent a matrix, and gives False otherwise. MatrixQ[expr, test] gives ...

ObservableModelQ (Built-in Mathematica Symbol)

ObservableModelQ[ss] gives True if the StateSpaceModel object ss is observable, and False otherwise.

RuntimeAttributes (Built-in Mathematica Symbol)

RuntimeAttributes is an option for Compile that specifies attributes for the compiled function it creates.

TimeConstrained (Built-in Mathematica Symbol)

TimeConstrained[expr, t] evaluates expr, stopping after t seconds. TimeConstrained[expr, t, failexpr] returns failexpr if the time constraint is not met.

Constructing Matrices (Mathematica Tutorial)

Functions for constructing matrices. This generates a 2×2 matrix whose i,j^th entry is a[i,j]. Here is another way to produce the same matrix.

PositiveDefiniteMatrixQ (Built-in Mathematica Symbol)

PositiveDefiniteMatrixQ[m] tests whether m is a positive definite matrix.