reduced duplicate code

include/aare/NDView.hpp

@@ -178,6 +178,22 @@ class NDView : public ArrayExpr<NDView<T, Ndim>, Ndim> {
     const T *data() const { return buffer_; }
     void print_all() const;
 
+    /**
+     * @brief Create a subview of a range of the first dimension. 
+     * This is useful for splitting a batches of frames in parallel processing.
+     * @param first The first index of the subview (inclusive).
+     * @param last The last index of the subview (exclusive).
+     * @return A new NDView that is a subview of the current view.
+     * @throws std::runtime_error if the range is invalid.
+     */
+    NDView sub_view(ssize_t first, ssize_t last) const {
+        if (first < 0 || last > shape_[0] || first >= last)
+            throw std::runtime_error(LOCATION + "Invalid sub_view range");
+        auto new_shape = shape_;
+        new_shape[0] = last - first;
+        return NDView(buffer_ + first * strides_[0], new_shape);
+    }
+
   private:
     T *buffer_{nullptr};
     std::array<ssize_t, Ndim> strides_{};

include/aare/calibration.hpp

@@ -3,6 +3,7 @@
 #include "aare/NDArray.hpp"
 #include "aare/NDView.hpp"
 #include "aare/defs.hpp"
+#include "aare/utils/par.hpp"
 #include "aare/utils/task.hpp"
 #include <cstdint>
 #include <future>
@@ -111,35 +112,30 @@ void apply_calibration(NDView<T, 3> res, NDView<uint16_t, 3> raw_data,
     for (const auto &lim : limits)
         futures.push_back(std::async(
             static_cast<void (*)(NDView<T, 3>, NDView<uint16_t, 3>,
-                                 NDView<T, Ndim>, NDView<T, Ndim>, int, int)>(
+                                 NDView<T, Ndim>, NDView<T, Ndim>, int,
+                                 int)>(
                 apply_calibration_impl),
             res, raw_data, ped, cal, lim.first, lim.second));
     for (auto &f : futures)
         f.get();
 }
 
+
 std::pair<NDArray<size_t, 3>, NDArray<size_t, 3>>
 sum_and_count_per_gain(NDView<uint16_t, 3> raw_data);
 
 std::pair<NDArray<size_t, 2>, NDArray<size_t, 2>>
 sum_and_count_g0(NDView<uint16_t, 3> raw_data);
 
-
 template <typename T>
 NDArray<T, 2> calculate_pedestal_g0(NDView<uint16_t, 3> raw_data,
-                                 ssize_t n_threads) {
+                                    ssize_t n_threads) {
     std::vector<std::future<std::pair<NDArray<size_t, 2>, NDArray<size_t, 2>>>>
         futures;
     futures.reserve(n_threads);
-    auto limits = split_task(0, raw_data.shape(0), n_threads);  
-    // make subviews for each thread
-    std::vector<NDView<uint16_t, 3>> subviews;
-    for (const auto &lim : limits) {
-        subviews.emplace_back(
-            raw_data.data() + lim.first * raw_data.strides()[0],
-            std::array<ssize_t, 3>{lim.second - lim.first, raw_data.shape(1),
-                                   raw_data.shape(2)});
-    }
+
+    auto subviews = make_subviews(raw_data, n_threads);
+
     for (auto view : subviews) {
         futures.push_back(std::async(
             static_cast<std::pair<NDArray<size_t, 2>, NDArray<size_t, 2>> (*)(
@@ -157,26 +153,17 @@ NDArray<T, 2> calculate_pedestal_g0(NDView<uint16_t, 3> raw_data,
     }
 
     return safe_divide<T>(accumulator, count);
-
 }
 
-
 template <typename T>
 NDArray<T, 3> calculate_pedestal(NDView<uint16_t, 3> raw_data,
                                  ssize_t n_threads) {
     std::vector<std::future<std::pair<NDArray<size_t, 3>, NDArray<size_t, 3>>>>
         futures;
     futures.reserve(n_threads);
-    auto limits = split_task(0, raw_data.shape(0), n_threads);
 
-    // make subviews for each thread
-    std::vector<NDView<uint16_t, 3>> subviews;
-    for (const auto &lim : limits) {
-        subviews.emplace_back(
-            raw_data.data() + lim.first * raw_data.strides()[0],
-            std::array<ssize_t, 3>{lim.second - lim.first, raw_data.shape(1),
-                                   raw_data.shape(2)});
-    }
+    auto subviews = make_subviews(raw_data, n_threads);
+
     for (auto view : subviews) {
         futures.push_back(std::async(
             static_cast<std::pair<NDArray<size_t, 3>, NDArray<size_t, 3>> (*)(

include/aare/utils/par.hpp

@@ -1,7 +1,10 @@
+#pragma once
 #include <thread>
 #include <utility>
 #include <vector>
 
+#include "aare/utils/task.hpp"
+
 namespace aare {
 
 template <typename F>
@@ -15,4 +18,17 @@ void RunInParallel(F func, const std::vector<std::pair<int, int>> &tasks) {
         thread.join();
     }
 }
+
+
+template <typename T>
+std::vector<NDView<T,3>> make_subviews(NDView<T, 3> &data, ssize_t n_threads) {
+    std::vector<NDView<T, 3>> subviews;
+    subviews.reserve(n_threads);
+    auto limits = split_task(0, data.shape(0), n_threads);
+    for (const auto &lim : limits) {
+        subviews.push_back(data.sub_view(lim.first, lim.second));
+    }
+    return subviews;
+}
+
 } // namespace aare

include/aare/utils/task.hpp

@@ -1,4 +1,4 @@
-
+#pragma once
 #include <utility>
 #include <vector>