如何在调用mapreduce函数时将参数传递给map函数?

pu3pd22g  于 2021-05-29  发布在  Hadoop
关注(0)|答案(1)|浏览(471)

我有一个mapreduce函数,它的输出应该反馈给另一个mapreduce函数,代码如下

function clustering = parallel_clustering_kmeans(data)
%% find first clustering from all chunks
result = mapreduce(data,@k_means_Mapper,@k_means_Reducer);
result = readall(result);
index = result{:,1};
index = cell2mat(cellfun(@str2num,strrep(index,',',' '),'un',0));
clustering = mapreduce(data,@k_means_Mapper_second,@k_means_Reducer);
end

第一个函数很好地工作result=mapreduce(data,@k_means_mapper,@k_means_reducer); 但是,我想将索引作为k\u means\u mapper\u second的参数传递
代码必须如下

function k_means_Mapper_second(data,index,intermidiateValuesOut)
distance = zeros(size(data,1),size(index,1));
parfor i = 1:size(data,1)
    for j = 1:size(index,1)
        distance(i,j) =  sum((data(i,:)-index(j,:)).^2).^0.5;
    end
end
for i = 1:size(distance,1)
    x = distance(i,:);
    [~,ind] = min(x);
    key = combine_values(data(i,:));
    addmulti(intermidiateValuesOut,key,ind);
end
end

我的问题是如何将索引作为参数传递给最后一行中的k\u means\u mapper\u second函数

clustering = mapreduce(data,@k_means_Mapper_second,@k_means_Reducer);

提前谢谢

iqxoj9l9

iqxoj9l91#

您需要将您的函数 Package 在一个匿名函数中,该匿名函数接受 mapreduce 然后调用函数,只传递相关的值。对于您的情况,它看起来像:

mapperFunc = @(data, info, interim)k_means_Mapper_second(data, index, interim);
clustering = mapreduce(data, mapperFunc, @k_means_Reducer);

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