custom_loss_fn_miml.py

def loss_fn(y_true,y_pred):
    loss = 0
    loss -= (positive_weights['desert']*y_true[0]*K.log(y_pred[0]) + negative_weights['desert']*(1-y_true[0])*K.log(1-y_pred[0]))
    loss -= (positive_weights['mountains']*y_true[1]*K.log(y_pred[1]) + negative_weights['mountains']*(1-y_true[1])*K.log(1-y_pred[1]))
    loss -= (positive_weights['sea']*y_true[2]*K.log(y_pred[2]) + negative_weights['sea']*(1-y_true[2])*K.log(1-y_pred[2]))
    loss -= (positive_weights['sunset']*y_true[3]*K.log(y_pred[3]) + negative_weights['sunset']*(1-y_true[3])*K.log(1-y_pred[3]))
    loss -= (positive_weights['trees']*y_true[4]*K.log(y_pred[4]) + negative_weights['trees']*(1-y_true[4])*K.log(1-y_pred[4]))

    return loss