// Copyright 1999 David Bourne david@boomer.org

var kel;
var cpmax;
var vd;
var weight;

function c1607a(form1)
{

	document.form1.cpmax.value = roundit((40-4)*Math.random()+4,2);
	document.form1.cpmin.value = roundit((3.5-0.25)*Math.random()+0.25,2);
	
	document.form1.vd.value = roundit((1.2-0.05)*Math.random()+0.05,3);
	document.form1.km.value = roundit((0.1-0.005)*Math.random()+0.005,2);
	document.form1.dslope.value = roundit((0.01-0.001)*Math.random()+0.001,2);

	document.form1.weight.value = roundit(Math.round((120-25)*Math.random()+25),3);
	document.form1.age.value = roundit((65-18)*Math.random()+18,2);

	document.form1.serumcr.value = roundit((3-0.4)*Math.random()+0.4,3);

	if (Math.random() > 0.5)
	{
		document.form1.sex[0].checked = false;
		document.form1.sex[1].checked = true;
	}
	else
	{
		document.form1.sex[0].checked = true;
		document.form1.sex[1].checked = false;
	}
	
	document.form1.crcl.value = "";
	document.form1.kel.value = "";
	document.form1.r.value = "";
	document.form1.tau.value = "";

	document.form2.r.value = "";
	document.form2.tau.value = "";
	document.form2.mdose.value = "";
	document.form2.tau1.value = "";
	document.form2.ldose.value = "";
	
}
function ckt(form1)
{
	if (document.form1.cpmax.value.length< 1)
	{
		alert ("Please enter a Cpmax value");
		return false;
	}

	cpmax   = document.form1.cpmax.value;
 	cpmin   = document.form1.cpmin.value;
	vd      = document.form1.vd.value;
	km      = document.form1.km.value;
	dslope  = document.form1.dslope.value;

	weight  = document.form1.weight.value;
	age     = document.form1.age.value;
	serumcr = document.form1.serumcr.value;

	if (document.form1.sex[0].checked == true)
	{
		sex = 1.0;
	}
	else
	{
		sex = 0.85;
	}

	crcl = ((140-age)*weight*sex)/(72.0*serumcr);
	kel = 1.0*km + dslope*crcl;
	r = cpmin/cpmax;
	tau = Math.log(cpmax/cpmin)/kel;

	document.form1.crcl.value = roundit(crcl,3);
	document.form1.kel.value  = roundit(kel,3);
	document.form1.r.value  = roundit(r,4);
	document.form1.tau.value  = roundit(tau,3);

}

function ml(form2)
{
	if (document.form2.tau.value.length< 1)
	{
		alert ("Please enter a new Tau value");
		return false;
	}

	tau = document.form2.tau.value;
	r = Math.exp(-1.0*kel*tau);
	mdose = cpmax*vd*weight*(1-r);
	ldose= cpmax*vd*weight;document.form2.r.value  = roundit(r,4);
	document.form2.mdose.value  = roundit(mdose,3);
	document.form2.ldose.value  = roundit(ldose,3);
	document.form2.tau1.value  = roundit(tau,3);
	
}

function roundit(a,b)

// a is value and b is number of significant digits returned

{
         c = b - Math.round(0.5 + (Math.log(a)/Math.log(10)));
         c = Math.pow(10,c);
         c = Math.round(c*a)/c;
         return c;
}