Runge Kutta Sine-Gordan equaiton.

[seagulloftime]

Apologies if this is in the wrong place, but could someone explain to me how I go about converting the sine-gordan equation with 2 double derivatives into one with a single derivative, or how I alter the rung-kutta algorithm to accommodate such a double derivative?

 

[HallsofIvy]

"Runge-Kutta" is a numerical method of solving ordinary differential equations so your first step should be to "separate" the variables to give you two ordinary differential equations. Then apply Runge-Kutta to both.