Merge branch 'oskar-nearest-neighbor' into 'master'

Select nearest neighbor frequency in oskar dataset

See merge request RD/EveryBeam!136

cpp/oskar/oskardataset.cc

@@ -5,26 +5,52 @@
 #include <cassert>
 #include <stdexcept>
 
+#include <cstring>
+#include <limits>
 #include "oskardataset.h"
 
 Dataset::Dataset(H5::H5File& h5_file, const unsigned int freq) {
-  // Try to read coefficients for this frequency
-  std::string dataset_name = std::to_string((int)(freq / 1e6));
+  H5::DataSet dataset;
+  const int freq_mhz = (int)(freq / 1e6);
+  try {
+    // Try to find exact match
+    const std::string dataset_name = std::to_string(freq_mhz);
+    dataset = h5_file.openDataSet(dataset_name);
+  } catch (H5::FileIException& e) {
+    // Find nearest neighbor
+    int dfreq = std::numeric_limits<int>::max();
+    int freq_nearest = 0;
+    for (size_t i = 0; i < h5_file.getNumObjs(); ++i) {
+      const int h5_freq = stoi(h5_file.getObjnameByIdx(i));
+      if (std::abs(h5_freq - freq_mhz) < dfreq) {
+        dfreq = std::abs(h5_freq - freq_mhz);
+        freq_nearest = h5_freq;
+      }
+    }
+    std::cout << "Could not load dataset for frequency "
+              << std::to_string(freq_mhz)
+              << " MHz, using the nearest neighbor with frequency "
+              << freq_nearest << " MHz instead" << std::endl;
 
+    const std::string dataset_name = std::to_string(freq_nearest);
     try {
-    // Open dataset
-    H5::DataSet dataset = h5_file.openDataSet(dataset_name);
+      dataset = h5_file.openDataSet(dataset_name);
+    } catch (H5::FileIException& e) {
+      throw std::runtime_error("Could not load dataset for frequency " +
+                               dataset_name + "MHz.");
+    }
+  }
 
   // Read dataset dimensions
   H5::DataSpace dataspace = dataset.getSpace();
-    unsigned int rank = dataspace.getSimpleExtentNdims();
+  const size_t rank = dataspace.getSimpleExtentNdims();
   assert(rank == dataset_rank_);
 
   // Get dimensions
   std::vector<hsize_t> dims(rank);
   dataspace.getSimpleExtentDims(dims.data(), NULL);
-    auto nr_elements = dims[0];
-    auto nr_coeffs = dims[1];
+  const size_t nr_elements = dims[0];
+  const size_t nr_coeffs = dims[1];
   assert(dims[2] == 4);  // tetm*pol
 
 // Coefficient data stored as:
@@ -38,8 +64,8 @@ Dataset::Dataset(H5::H5File& h5_file, const unsigned int freq) {
 #endif
 
   // Check total number of coefficients to find l_max
-    auto l_max_d = sqrt(nr_coeffs + 1) - 1;
-    auto l_max = (int)round(l_max_d);
+  const double l_max_d = sqrt(nr_coeffs + 1) - 1;
+  const size_t l_max = (size_t)round(l_max_d);
 #ifndef NDEBUG
   std::cout << "l_max: " << l_max << std::endl;
 #endif
@@ -58,12 +84,6 @@ Dataset::Dataset(H5::H5File& h5_file, const unsigned int freq) {
   H5::DataType data_type = dataset.getDataType();
   assert(data_type.getSize() == sizeof(std::complex<double>));
   dataset.read(data_.data(), data_type, dataspace);
-  } catch (H5::FileIException& e) {
-    std::stringstream message;
-    message << "Could not load dataset for frequency " << dataset_name
-            << " Mhz";
-    throw std::runtime_error(message.str());
-  }
 }
 
 size_t Dataset::GetIndex(const unsigned int element) const {

cpp/oskar/oskardataset.h

@@ -36,9 +36,9 @@ class Dataset {
 
   // Members
   std::vector<std::complex<double>> data_;
-  unsigned int nr_elements_;
-  unsigned int nr_coeffs_;
-  unsigned int l_max_;
+  size_t nr_elements_;
+  size_t nr_coeffs_;
+  size_t l_max_;
 };
 
 #endif