gtk wave not dispalying waveform

HI.

I written traffic signal program .Ran on ghdl simulator gtk wave not displaying waveform/

commands used :ghdl -a tra.vhd

ghdl -e tra

ghdl -r tra --vcd=ha.vcd=$--stop-time=100ns

gtkwave tra.vcd

library ieee;

use ieee.std_logic_1164.all;

entity tra is

port(rst,clk : in std_logic;

q : out std_logic_vector(2 downto 0));

end;

architecture fsm of tra is

type state_type is(red,green,yellow);

signal ps,ns1 : state_type;

begin

process(clk,rst)

begin

if(rst = '0')then

ps <= red;

elsif clk'event and clk='1'then

ps <= ns1;

end if;

end process;

process(ps,ns1)

begin

case ps is

when red =>

q <="001";

ns1<= green;

when green =>

q <= "010";

ns1 <= yellow;

when yellow =>

q <= "100";

ns1 <= red;

end case;

end process;

end fsm;

Thanks in advanvce

Regards

Raghavendra