% dpdtheta - derivative for function P(theta) in terms of (theta,P(theta))

% Philip D Loewen, 2010-02-24; 2011-03-15

function dpdt = dpdtheta(theta,P)

global global_GAMMA

g = global_GAMMA;

[V,dVdtheta] = vdv(theta);
[Q,dQdtheta] = qdq(theta);

dpdt = -g * P .* dVdtheta ./ V + (g-1) .* dQdtheta ./ V;