A rat to inhabit RatLab.
It has a field of view extending to viewAngle degrees either side of straight on. This range is binned into viewNPix bins for export to its network if specified.
Where there are markers defined in the environment it registers only those within range. The stepDistance, stepAngle and stepTime give the step size and duration when controlled from the keyboard.
Under random motion, the rat takes random steps of mean length avgRanD. The standard deviation of step length is sdRanD and of the angle sdRanAngle (degrees). Motion is governed by two autoregressive processes with parameters arpLin and arpRot. In each case the next random value vn satisfies vn = a vo + (1-a) u where vo is the last value used, a is the regression parameter arpLin or arpRot and u is a new gaussian random variable scaled approprately to give the desired overall variance. Values of the regression parameter near 1 give a lot of continuity in the motion. For a = 0 steps are completely independent.
The uniform option overrides this process, causing the rat simply to take a step of length uniformly distributed between 0 nad avgRanD and angle uniformly distributed between +sdRanAngle and -sdRanAngle.