#已经取了前k个
def precision_and_recall(ranked_list, ground_list):
    hits = 0
    for i in range(len(ranked_list)):
        id = ranked_list[i]
        if id in ground_list:
            hits += 1
    pre = hits / (1.0 * len(ranked_list) if len(ground_list) != 0 else 1)
    rec = hits / (1.0 * len(ground_list) if len(ground_list) != 0 else 1)
    return pre, rec

def IDCG(n):
    idcg = 0
    for i in range(n):
        idcg += 1 / math.log(i + 2, 2)
    return idcg

def nDCG(ranked_list, ground_truth):
    dcg = 0
    idcg = IDCG(len(ground_truth))
    for i in range(len(ranked_list)):
        id = ranked_list[i]
        if id not in ground_truth:
            continue
        rank = i + 1
        dcg += 1 / math.log(rank + 1, 2)
    return dcg / idcg if idcg != 0 else 0

def AP(ranked_list, ground_truth):
    hits, sum_precs = 0, 0.0
    for i in range(len(ranked_list)):
        id = ranked_list[i]
        if id in ground_truth:
            hits += 1
            sum_precs += hits / (i + 1.0)
    if hits > 0:
        return sum_precs / len(ground_truth)
    else:
        return 0.0


def RR(ranked_list, ground_list):
    for i in range(len(ranked_list)):
        id = ranked_list[i]
        if id in ground_list:
            return 1 / (i + 1.0)
    return 0

2

def precision_recall_ndcg_at_k(k, rankedlist, test_matrix):
    idcg_k = 0
    dcg_k = 0
    n_k = k if len(test_matrix) > k else len(test_matrix)
    for i in range(n_k):
        idcg_k += 1 / math.log(i + 2, 2)

    b1 = rankedlist
    b2 = test_matrix
    s2 = set(b2)
    hits = [ (idx, val) for idx, val in enumerate(b1) if val in s2]
    count = len(hits)
    #print(hits)

    r = np.array(rankedlist)

    for c in range(count):
        dcg_k += 1 / math.log(hits[c][0] + 2, 2)
    #print(float(count / k))
    #print(float(count / len(test_matrix)))
    return float(count / k), float(count / len(test_matrix)), float(dcg_k / idcg_k)

def map_mrr_ndcg(rankedlist, test_matrix):
    ap = 0
    map = 0
    dcg = 0
    idcg = 0
    mrr = 0
    for i in range(len(test_matrix)):
        idcg += 1 / math.log(i + 2, 2)

    b1 = rankedlist
    b2 = test_matrix
    s2 = set(b2)
    hits = [ (idx, val) for idx, val in enumerate(b1) if val in s2]
    count = len(hits)

    for c in range(count):
        ap += (c+1) / (hits[c][0] + 1)
        dcg += 1 / math.log(hits[c][0] + 2, 2)

    if count != 0:
        mrr = 1 / (hits[0][0] + 1)

    if count != 0:
        map = ap / count

    return map, mrr, float(dcg / idcg)