simGetObjectPose(gate_name) randomly returns nan

[yannbouteiller]

Hello,

I have been working quite a while on debugging an algorithm where 'nan' appeared randomly to finally find that this snippet from the baseline is responsible:

def get_ground_truth_gate_poses(self):
        gate_names_sorted_bad = sorted(self.airsim_client.simListSceneObjects("Gate.*"))
        gate_indices_bad = [int(gate_name.split('_')[0][4:]) for gate_name in gate_names_sorted_bad]
        gate_indices_correct = sorted(range(len(gate_indices_bad)), key=lambda k: gate_indices_bad[k])
        gate_names_sorted = [gate_names_sorted_bad[gate_idx] for gate_idx in gate_indices_correct]
        for gate_name in gate_names_sorted:
            p = self.airsim_client.simGetObjectPose(gate_name)
            assert not math.isnan(p.position.x_val), f"DEBUG: {gate_name} p.position.x_val is {p.position.x_val}"
            assert not math.isnan(p.position.y_val), f"DEBUG: {gate_name} p.position.y_val is {p.position.y_val}"
            assert not math.isnan(p.position.z_val), f"DEBUG: {gate_name} p.position.z_val is {p.position.z_val}"
        return [self.airsim_client.simGetObjectPose(gate_name) for gate_name in gate_names_sorted]

This randomly returns 'nan's on random gates after calling airsim_client.reset() repeatedly.

Regards,
Yann.

[yannbouteiller]

This workaround does the trick for me:

MAX_NUMBER_OF_GETOBJECTPOSE_TRIALS = 10
def get_ground_truth_gate_poses(self):
        gate_names_sorted_bad = sorted(self.airsim_client.simListSceneObjects("Gate.*"))
        gate_indices_bad = [int(gate_name.split('_')[0][4:]) for gate_name in gate_names_sorted_bad]
        gate_indices_correct = sorted(range(len(gate_indices_bad)), key=lambda k: gate_indices_bad[k])
        gate_names_sorted = [gate_names_sorted_bad[gate_idx] for gate_idx in gate_indices_correct]
        res = []
        for gate_name in gate_names_sorted:
            p = self.airsim_client.simGetObjectPose(gate_name)
            cpt = 0
            while (math.isnan(p.position.x_val) or math.isnan(p.position.y_val) or math.isnan(p.position.z_val)) and cpt < MAX_NUMBER_OF_GETOBJECTPOSE_TRIALS:
                print(f"DEBUG: {gate_name} position is nan, retrying...")
                cpt = cpt + 1
                p = self.airsim_client.simGetObjectPose(gate_name)
            assert not math.isnan(p.position.x_val), f"ERROR: {gate_name} p.position.x_val is still {p.position.x_val} after {cpt} trials"
            assert not math.isnan(p.position.y_val), f"ERROR: {gate_name} p.position.y_val is still {p.position.y_val} after {cpt} trials"
            assert not math.isnan(p.position.z_val), f"ERROR: {gate_name} p.position.z_val is still {p.position.z_val} after {cpt} trials"
            res.append(p)
        return res

[madratman]

This is happening very rarely coz of an unreal APIs we're using the backend - getAllActors - which fail randomly.
I've incorporated your suggestion in the baseline racer. It makes sense for the simgetobjectpose API to return NaN when object is not found, and the user to check it coz of this edge case
Didn't want to throw an error, which might kill the user's script