Question

我有以下代码，该代码应该从modelService返回orgId，但不能与Optional

一起使用

#ifdef _OPENMP
   #include <omp.h>
#else
   #define omp_get_num_threads() 1
   #define omp_get_thread_num() 0
#endif


__inline static
void calculateClusterCentroIDs(int numCoords, int numObjs, int numClusters, float * dataSetMatrix, int * clusterAssignmentCurrent, float *clustersCentroID) {
    int * clusterMemberCount = (int *) calloc (numClusters,sizeof(float));
    // sum all points
    // for every point

    #pragma omp parallel
    {
        int nbOfThreads = omp_get_num_threads();
        int thisThread = omp_get_thread_num();
        // Schedule for the first step : process only cluster with ID in the [from , to[ range
        int clustFrom = (thisThread*numClusters)/nbOfThreads;
        int clustTo   = (thisThread+1 == nbOfThreads) ? numClusters : ((thisThread+1)*numClusters)/nbOfThreads;

        // Each thread will loop through all values of numObjs but only process them depending on activeCluster
        // The loop is skipped only if the thread was assigned no cluster
        if (clustTo>clustFrom){
            for (int i = 0; i < numObjs; ++i) {
                // which cluster is it in?
                int activeCluster = clusterAssignmentCurrent[i];

                if (activeCluster>=clustFrom && activeCluster<clustTo){
                    // update count of members in that cluster
                    ++clusterMemberCount[activeCluster];

                    // sum point coordinates for finding centroid
                    for (int j = 0; j < numCoords; ++j)
                        clustersCentroID[activeCluster*numCoords + j] += dataSetMatrix[i*numCoords + j];
                }
            }
        }

        #pragma omp barrier

        // now divide each coordinate sum by number of members to find mean/centroid
        // for each cluster
        #pragma omp for // straightforward
        for (int i = 0; i < numClusters; ++i) {
            if (clusterMemberCount[i] != 0)
                // for each coordinate
                for (int j = 0; j < numCoords; ++j)
                    clustersCentroID[i*numCoords + j] /= clusterMemberCount[i];  /// XXXX will divide by zero here for any empty clusters!
        }
    }
    free(clusterMemberCount);
}

此代码不起作用public Long getOrgId(String someId) { return this.getSpecialOrgId(someId).orElse(this.getById(someId).getOrgId()); } private Optional<Long> getSpecialOrgId(String someId) { return modelService.getModel(someId).map(Model::getOrgId).filter(this::isConditionTrue); }始终返回getSpecialOrgId

但是下面的代码很好用，不确定上面的代码有什么问题

empty

其中private Long getOrgId(String someId) { Optional<Long> orgIdFromModel = this.getSpecialOrgId(someId); if (orgIdFromModel.isPresent()) { return orgIdFromModel.get(); } return this.getById(someId).getOrgId(); } private Optional<Long> getSpecialOrgId(String someId) { Optional<Model> modelOptional = modelService.getModel(someId); if (modelOptional.isPresent()) { Model model = modelOptional.get(); if (isConditionTrue(model.getOrgId())) { return of(model.getOrgId()); } } return empty(); }始终是isConditionTrue，这是准确的代码，我仅更改了一些变量名

Answer 1

您似乎应该将orElse中的getOrgId替换为orElseGet(() -> getById(someId).getOrgId())。

Java可选地图和过滤器无法按预期工作

1 个答案: