Mathematics 
Solver for Fully Implicit ODEs
The solver ode15i
solves fully implicit differential equations of the form
using the variable order BDF method. The basic syntax for ode15i
is

A function that evaluates the left side of the differential equation of the form . 
tspan 
A vector specifying the interval of integration, [t0,tf] . To obtain solutions at specific times (all increasing or all decreasing), use tspan = [t0,t1,...,t f]. 
y0, yp0 
Vectors of initial conditions for and , respectively. The specified values must be consistent; that is, they must satisfy . Example: Solving a Fully Implicit ODE Problem shows how to use the function decic to compute consistent initial conditions. 

Optional integration argument created using the odeset function. See the odeset reference page for details. 
t 
Column vector of time points 
y 
Solution array. Each row in y corresponds to the solution at a time returned in the corresponding row of t . 
See the ode15i
reference page for more information about these arguments.
Examples: Solving Explicit ODE Problems  Example: Solving a Fully Implicit ODE Problem 
© 19942005 The MathWorks, Inc.