当我尝试为keras创建自定义指标时，我遇到了错误（Intersection over union） . 我想找到两个图像（张量）联合的交叉点
def IoU(y_true,y_pred):
y_true_f = K.flatten(y_true)
y_pred_f = K.flatten(y_pred)
#assert len(y_true_f) != len(y_pred_f)
y_true_f = y_true_f.eval(session = K.get_session())
y_pred_f = y_pred_f.eval(session = K.get_session())
union1 = [i for i,j in zip(y_true_f,y_pred_f) if i != j]
union2 = [j for i,j in zip(y_true_f,y_pred_f) if i != j]
intersection = [i for i,j in zip(y_true_f,y_pred_f) if i == j]
unionAll = union1 + union2 + intersection
return (np.sum(intersection) + smooth) / float(np.sum(unionAll)+ smooth)
error 我得到：
InvalidArgumentError（请参见上面的回溯）：您必须为占位符张量'activation_1_target'提供一个值，其中dtype为float和shape [？，？，？] [[Node：activation_1_target = Placeholderdtype = DT_FLOAT，shape = [？，？，？ ]，_ device =“/ job：localhost / replica：0 / task：0 / gpu：0”]] [[Node：metrics / IoU / Reshape / _5 = _Recvclient_terminated = false，recv_device =“/ job：localhost / replica： 0 / task：0 / cpu：0“，send_device =”/ job：localhost / replica：0 / task：0 / gpu：0“，send_device_incarnation = 1，tensor_name =”edge_8_metrics / IoU / Reshape“，tensor_type = DT_FLOAT， _device = “/作业：本地主机/复制：0 /任务：0 / CPU：0”]]