On 10/23/11 15:40, Karsten Ahnert wrote:
Dear community,
odeint is a library for solving ordinary differential equations [snip] The library and the documentation are available at the github:
https://github.com/headmyshoulder/odeint-v2 http://headmyshoulder.github.com/odeint-v2/doc/index.html [snip] The page:
http://headmyshoulder.github.com/odeint-v2/doc/boost_sandbox_numeric_odeint/... says: The equations of motion are given by x'' = -x + γ x'. This can be transformed to a system of two coupled first-order differential equations with new variables x and p=x'. To apply numerical integration one first has to design the right hand side of the equation w' = f(w) where in this case w = (x,p): which initially confused me because x was not a new variable as claimed by: new variables x and p=x' I think it would be clearer if it read: with new variables w_1=x and w_2=x'. and then: w = (w_1,w_2) which would emphasize that w was a vector and f was a function taking a vector and returning a vector. -regards, Larry