NDSolve

NDSolve[eqns, y, x, xmin, xmax] finds a numerical solution to the ordinary differential equations eqns for the function y with the independent variable x in the range xmin to xmax.

NDSolve[eqns, y, x, xmin, xmax, t, tmin, tmax] finds a numerical solution to the partial differential equations eqns.

NDSolve[eqns, , , ... , x, xmin, xmax] finds numerical solutions for the functions .

NDSolve gives results in terms of InterpolatingFunction objects.

NDSolve[eqns, y[x], x, xmin, xmax] gives solutions for y[x] rather than for the function y itself.

Differential equations must be stated in terms of derivatives such as y'[x], obtained with D, not total derivatives obtained with Dt.

NDSolve solves a wide range of ordinary differential equations as well as many partial differential equations.

In ordinary differential equations the functions must depend only on the single variable x. In partial differential equations they may depend on more than one variable.

The differential equations must contain enough initial or boundary conditions to determine the solutions for the completely.

Initial and boundary conditions are typically stated in form y[] == , y'[] == , etc., but may consist of more complicated equations.

The , , etc. can be lists, specifying that y[x] is a function with vector or general list values.

Periodic boundary conditions can be specified using y[] == y[].

The point that appears in the initial or boundary conditions need not lie in the range xmin to xmax over which the solution is sought.

The differential equations in NDSolve can involve complex numbers.

NDSolve can solve many differential-algebraic equations, in which some of the eqns are purely algebraic, or some of the variables are implicitly algebraic.

The can be functions of the dependent variables, and need not include all such variables.

The following options can be given:

NDSolve adapts its step size so that the estimated error in the solution is just within the tolerances specified by PrecisionGoal and AccuracyGoal.

The option NormFunction -> f specifies that the estimated errors for each of the should be combined using f[, , ... ].

AccuracyGoal effectively specifies the absolute local error allowed at each step in finding a solution, while PrecisionGoal specifies the relative local error.

If solutions must be followed accurately when their values are close to zero, AccuracyGoal should be set larger, or to Infinity.

The default setting of Automatic for AccuracyGoal and PrecisionGoal is equivalent to WorkingPrecision/2.

The setting for MaxStepFraction specifies the maximum step to be taken by NDSolve as a fraction of the range of values for each independent variable.

With DependentVariables->Automatic, NDSolve attempts to determine the dependent variables by analyzing the equations given.

Possible explicit settings for the Method option include:

With Method->"controller", Method->"submethod" or Method->"controller", Method->, , ... possible controller methods include:

Methods used mainly as submethods include:

See Section 3.9.1 and Section 3.9.7.

Implementation Notes: see Section A.9.4.

See also: DSolve, NIntegrate.

New in Version 2; modified in 5.0.

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