ELLVEL Average and instantaneous ellipse velocities. V=ELLVEL(KAPPA,LAMBDA,THETA,PHI,STR) where KAPPA and LAMBDA are the amplitude and linearity of a time-varying ellise, THETA is its time- varying orientation, and PHI is its time-varying phase, returns various measures of the ellispe 'velocity'. STR determines the velocity quantity to be output. STR Symbol Description ---------------------------------------------------------------- 'geo' VM Geometric mean velocity 'ave' VBAR Period-averaged speed 'kin' VEKE Kinetic energy velocity 'cir' VGAMMA Circulation velocity 'azi' VAZ Instantaneous azimuthal velocity 'ins' VI Instantaneous speed All are signed quantities reflecting the direction of motion. That is, a velocity is defined to be positive when the ellipse is orbited in the mathematically positive (counterclockwise) sense, and negative when the ellipse is orbited in the mathematically negative sense. VM=ELLVEL(KAPPA,LAMBDA,THETA,PHI) with STR omitted returns VM, the geometric mean velocity. This is a basic of ellipse velocity that is analagous to the geometric mean radius as a measure of ellipse size. ELLVEL(DT,...,) optionally uses DT as the data sample rate, with a default value of DT=1. DT is a scalar. ELLVEL(DT,...,FACT,STR) optionally converts the physical units of velocity through a multiplication by FACT, with a default value of FACT=1. For example, FACT=1e5 converts kilometers into centimeters, while FACT=1e5/24/3600 converts km/day into cm/sec. ____________________________________________________________________ Cell array input/output If ELLVEL is given cell array input, it returns cell array output. Thus KAPPA, LAMBDA, THETA, and PHI may each be cell arrays of the same size, where each element in the cell array is a numerical array. VM and other velocity measures will be also cell arrays of this size. In this case ELLVEL(DT,...) also works with DT a scalar or an array whose length is the number of elements in the cell arrays. ____________________________________________________________________ See also ELLRAD, ELLPARAMS, ELLDIFF. Usage: v=ellvel(kappa,lambda,theta,phi); v=ellvel(dt,kappa,lambda,theta,phi,1e5); vbar=ellvel(kappa,lambda,theta,phi,'ave'); 'ellvel --f' generates a sample figure. __________________________________________________________________ This is part of JLAB --- type 'help jlab' for more information (C) 2005--2014 J.M. Lilly --- type 'help jlab_license' for details