// Formas de onda de un sistema de primer orden.
// Autor: Juan Claudio Regidor
// Versi—n: 1.1
// Fecha: 27/may/02
//

title "Sistema de primer orden"

help
{@
Formas de onda de un sistema de primer orden.
@}

variable tau	// ctte. de tiempo
variable imp
variable recta
variable w

init (tau, imp, recta) = init

menu "Respuesta al escal—n" _checkmark(imp == 0) imp = newgr(imp)
menu "Mostrar pendiente" _checkmark(recta == 1) recta = newgr(recta)
separator
menu "800x600" _checkmark(w == 1) w = graf_layout(1)
menu "1024x768" _checkmark(w == 2) w = graf_layout(2)
menu "1152x768" _checkmark(w == 3) w = graf_layout(3)

figure "Respuesta primer orden"
	draw exponencial(0, 10, tau, imp, recta)

figure "Valor de tau"
	draw tau_sel(tau)
	mousedrag (tau) = dragSlider(tau, _nb, _x1)



functions
{@
function (tau, imp, recta) = init
	tau = 2;
	imp = 1;
	recta = 0;
	graf_layout(0);



function w1 = graf_layout(w)
	w1 = w;
	switch w
	case 0
		x = 510; y = 400;
	case 1
		x = 800; y = 600;
	case 2
		x = 1024; y = 768;
	case 3
		x = 1152; y = 768;
	end
	x=x-26;y=y-80; ux=x/8; uy=y/8; uy3 = 10;
	subplots('Respuesta primer orden\nValor de tau');
	subplotpos([0,ux,0,uy-uy3; 0,ux,uy-uy3,uy]);



	
function (gr) = newgr(gr)
	gr = 1 - gr;


function exponencial(tmin, tmax, tau, imp, recta)
	scale([tmin, tmax, -0.05, 1.05]);
	//plotoption xgrid;
	//plotoption ygrid;
	line([0, 1], 1, '-');
	line([0, 1], 0);
	(t, x) = sigExp(tmin, tmax+1, 0, tau, false);
	if(imp == 1)
		plot(t, x, 'b');
		text(5, 0.8, 'exp(-t/tau)', 'lb');
	else
		plot(t, 1 - x, 'b')
		text(5, 0.2, '1 - exp(-t/tau)', 'lb');
	end;
	line([1, 0], 0);
	if(recta == 1)
		if(imp == 1)
			line([1/tau, 1], 1, 'r');
			line([0, 1], exp(-1), 'g-');
			text(10, exp(-1)+0.02, '0,368', 'rb');
		else
			line([-1/tau, 1], 0, 'r');
			line([0, 1], 1-exp(-1), 'g-');
			text(10, 1-exp(-1)+0.02, '0,632', 'rb');
		end
		line([1, 0], tau, 'g-');
		text(tau+0.05, 0.05,'t=tau', 'l');
	end;

function tau_sel(tau)
	settabs('tau = 0.00   \t');
	slider(sprintf('tau = %.2f', tau), [tau], [0, 5], '', '', 1);


function (tau) = dragSlider(tau, nb, x1)
	if isempty(nb)
		cancel;
	end
	tau = x1;


function (t, x) = sigExp(tmin, tmax, t0, tau, backward)
	n = (tau > .2)? 200 : 400;
	if backward
		if t0 > tmax
			t = tmin + (tmax - tmin) * (0:n) / n;
			x = exp((t - t0) / tau);
		elseif t0 < tmin
			t = [tmin, tmax];
			x = [0, 0];
		else
			t = [tmin+(t0-tmin)*(0:n)/n, t0, tmax];
			x = [exp((tmin+(t0-tmin)*(0:n)/n-t0)/tau), 0, 0];
		end
	else
		if t0 < tmin
			t = tmin + (tmax - tmin) * (0:n) / n;
			x = exp((t0 - t) / tau);
		elseif t0 > tmax
			t = [tmin, tmax];
			x = [0, 0];
		else
			t = [tmin, t0, t0+(tmax-t0)*(0:n)/n];
			x = [0, 0, exp((t0-(t0+(tmax-t0)*(0:n)/n))/tau)];
		end
	end

@}