use Test::More tests => 1;
use File::Spec;
use lib File::Spec->catfile("..","lib");
use Math::ODE;
use Data::Dumper;

# analytic solution is y(x) = 2 e^{-x}
my $o = new Math::ODE ( file => 'data',
			step => 0.1,
			initial => [2], 
			ODE => [ \&DE1 ], 
			t0 => 0,
			tf => 1 );
$o->evolve;
my $res = abs($o->error - $o->{step}**4 );
ok( $res < 1e-12, "returns correct amount of error , res=$res" );
sub DE1 { my ($t,$y) = @_; return -$y->[0]; }