$arr= pack("d",1) . pack("d",1.5) . pack("d",3);

##</code><code>##

    $arr= pack("d3",1,1.5,3);

##</code><code>##

    my @arr= ( 1, 1.5, 3 );
    my $arr= pack "d*", @arr;
    my $res= $obj->Call( $arr, 0+@arr );