physics.h

/*
	Copyright (c) 1999-2008, Phillip Stanley-Marbell (author)
 
	All rights reserved.

	Redistribution and use in source and binary forms, with or without 
	modification, are permitted provided that the following conditions
	are met:

	*	Redistributions of source code must retain the above
		copyright notice, this list of conditions and the following
		disclaimer.

	*	Redistributions in binary form must reproduce the above
		copyright notice, this list of conditions and the following
		disclaimer in the documentation and/or other materials
		provided with the distribution.

	*	Neither the name of the author nor the names of its
		contributors may be used to endorse or promote products
		derived from this software without specific prior written 
		permission.

	THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
	FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
	COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
	INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
	BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
	LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 
	CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 
	ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
	POSSIBILITY OF SUCH DAMAGE.
*/

typedef struct Signalsrc Signalsrc;
typedef struct Sensor Sensor;
typedef struct Actuator Actuator;

enum
{
	/*		Physical phenomena			*/
	MAX_SIGNAL_SRCS	= 32,
	MAX_SIGNALSRC_SUBSCRIBERS = 512,
	MAX_NODE_SENSORS = 8,
};

struct Signalsrc
{
	int	valid;
	int	ID;

	/*							*/
	/*	During each sampling period, signals from	*/
	/*	all sources of the same 'type' are summed	*/
	/*	at all subscribed nodes. Thus, you can		*/
	/*	define, e.g., 2 phenomyna of the same type,	*/
	/*	that interfere w/ each other.			*/
	/*	You can implement non-monotonic degradation	*/
	/*	effects like shadowing, multipath etc.,		*/
	/*	by defining additional signals of the same	*/
	/*	type with negative amplitudes, located at	*/
	/*	the positions of pronounced attenuation, and	*/
	/*	furthermore, recall all signals can have	*/
	/*	a flexible spatial attenuation relation.	*/
	/*							*/
	/*	It would be nice to implement a graphical tool	*/
	/*	that defines a terrain (e.g. as contour maps)	*/
	/*	and signal sources, and outputs configs to	*/
	/*	be provided to the simulator as input		*/
	/*							*/
	int		type;


	/*	A textual description of the phenomenon		*/
	char		*description;


	/*	Nodes that are subscribed to this phenomenon	*/
	Sensor*		subscribed_sensors[MAX_SIGNALSRC_SUBSCRIBERS];
	int		numsubscribed;

	/*							*/
	/*	The quantum of updates to subscribers of Phn.	*/
	/*	Physical phenomena such as sound propoagation	*/
	/*	will have larger constants than, say, EM rad.	*/
	/*							*/
	double		updates_tau;


	/*							*/
	/*	The signal propagation speed in environment	*/
	/*							*/
	double		propagation_speed;


	/*							*/
	/*	  Constants defining spatial attenuation. 	*/
	/*	The general form is:				*/
	/*							*/
	/* signal = S*(A*x^m + B*x^n + C*x^o + D*x^p + E*K^(F*x^q + G*x^r + H*x^s + I*x^t))*/
	/*							*/
	/*	where a..d and m..p are constants defined	*/
	/*	for each phenomenon, defaulting to 0. Thus,	*/
	/*	e.g., for wireless comms.:			*/
	/*		a = 1, m = -2, i.e.:			*/
	/*		signal = signal * 1/r^2			*/
	/*	Ideally, you should use a tool like		*/
	/*	Mathematica to fit data representative	of	*/
	/*	the physical phenomenon to the equation		*/
	/*	above, to obtain the coeffs.			*/
	/*							*/
	double		const_coeff_A;
	double		const_coeff_B;
	double		const_coeff_C;
	double		const_coeff_D;
	double		const_coeff_E;
	double		const_coeff_F;
	double		const_coeff_G;
	double		const_coeff_H;
	double		const_coeff_I;

	double		const_base_K;

	double		const_pow_m;
	double		const_pow_n;
	double		const_pow_o;
	double		const_pow_p;
	double		const_pow_q;
	double		const_pow_r;
	double		const_pow_s;
	double		const_pow_t;

	/*							*/
	/*	Positioning of signal source in 3-space		*/
	/*	and trajectory / speed of motion.		*/
	/*							*/
	double		xloc;
	double		yloc;
	double		zloc;
	double		*xlocs;
	double		*ylocs;
	double		*zlocs;

	char		*trajectory_file;
	int		nlocations;
	int		trajectory_rate;
	int		looptrajectory;


	/*							*/
	/*	Variation of unattenuated signal in time.	*/
	/*	The array of values is may be read from a file.	*/
	/*	E.g., for sound waves, this is basically	*/
	/*	the audio signal. The sampling rate defines	*/
	/*	how often subscribers to phenomenon have their	*/
	/*	sensor values updated. Sampling rates smaller	*/
	/*	than the minimum simulation step are 		*/
	/*	thresholded. Sampling rate is in samples/sec	*/
	/*	A sample rate of 0 is used for constant signals	*/
	/*							*/
	double		sample;
	double		*samples;

	char		*samples_file;
	int		nsamples;
	int		sample_rate;
	int		loopsamples;
	int 		interpolation;
};

struct Sensor
{
	/*		Owner is..				*/
	void		*parent;

	/*		Which sensor are we:			*/
	int		which;		
	
	/*							*/
	/*		Doesn't make sense to have the sensor	*/
	/*	values be double precision.			*/
	/*							*/
	float		reading;
};

struct Actuator
{
	Signalsrc	signalsrc;
};