loncom/homework/functionplotresponse.pm - diff

Return to functionplotresponse.pm CVS log

Up to [LON-CAPA] / loncom / homework

version 1.27, 2010/11/07 12:28:28	version 1.28, 2010/11/07 13:15:28
Line 591 sub populate_arrays {	Line 591 sub populate_arrays {
$xiold=$xi;	$xiold=$xi;
# Function value	# Function value
$Apache::functionplotresponse::func[$xi]=&cubic_hermite($t,@yparms);	$Apache::functionplotresponse::func[$xi]=&cubic_hermite($t,@yparms);
	# Chain rule
# dy/dx=dy/dt/(dx/dt)	# dy/dx=dy/dt/(dx/dt)
my $dxdt=&ddt_cubic_hermite($t,@xparms);	my $dxdt=&ddt_cubic_hermite($t,@xparms);
if ($dxdt) {	if ($dxdt) {
$Apache::functionplotresponse::dfuncdx[$xi]=&ddt_cubic_hermite($t,@yparms)/$dxdt;	$Apache::functionplotresponse::dfuncdx[$xi]=&ddt_cubic_hermite($t,@yparms)/$dxdt;
}	}
# d^2y/dx^2	# Faa di Bruno
	# d^2y/dx^2=(d^2y/dt^2)/(dx/dt)^2+(dy/dt)/(d^2x/dt^2)
my $d2xdt2=&d2dt2_cubic_hermite($t,@xparms);	my $d2xdt2=&d2dt2_cubic_hermite($t,@xparms);
if ($d2xdt2) {	if (($dxdt) && ($d2xdt2)) {
$Apache::functionplotresponse::d2funcdx2[$xi]=&d2dt2_cubic_hermite($t,@yparms)/$d2xdt2;	$Apache::functionplotresponse::d2funcdx2[$xi]=
	&d2dt2_cubic_hermite($t,@yparms)/($dxdt*$dxdt)
	+&ddt_cubic_hermite($t,@yparms)/$d2xdt2;
}	}
}	}
}	}