Copy databox_wrapper.hpp from Singe as a starting point for discussion.

spiner/databox_wrapper.hpp

@@ -0,0 +1,72 @@
+#ifndef SINGE_UTIL_DATABOXWRAPPER_HPP
+#define SINGE_UTIL_DATABOXWRAPPER_HPP
+
+#include "singe/util/databox.hpp"
+#include "singe/util/portability_macros.hpp"
+
+#include <cmath>
+
+namespace singe {
+namespace util {
+
+// ================================================================================================
+
+// a wrapper to (a) adapt the interface and (b) handle extrapolation off the table
+// -- note that we assume this is a 1D databox
+template <typename DataType_t, typename LowerExtrapolation, typename UpperExtrapolation>
+class DataBoxWrapper
+{
+private:
+    DataBox<DataType_t> databox_;
+    // Avoid re-calculating temperature bounds on every call
+    DataType_t Tlo_;
+    DataType_t Thi_;
+
+public:
+    SINGE_PORTABLE_FUNCTION DataBoxWrapper(DataBox<DataType_t> databox)
+        : databox_{databox} // MUST be initialized before Tlo_ and Thi_
+        , Tlo_{get_temperature(0)}
+        , Thi_{get_temperature(size() - 1)}
+    {}
+    SINGE_PORTABLE_FUNCTION constexpr DataType_t get_logT(int const index) const
+    {
+        return databox_.range(0).x(index);
+    }
+    SINGE_PORTABLE_FUNCTION constexpr DataType_t get_temperature(int const index) const
+    {
+        return std::exp(get_logT(index));
+    }
+    SINGE_PORTABLE_FUNCTION constexpr DataType_t get_value(int const index) const
+    {
+        return databox_(index);
+    }
+    SINGE_PORTABLE_FUNCTION constexpr DataType_t get_logV(int const index) const
+    {
+        return std::log(get_value(index));
+    }
+    SINGE_PORTABLE_FUNCTION constexpr int size() const
+    {
+        return databox_.dim(1);
+    }
+    SINGE_PORTABLE_FUNCTION constexpr DataType_t operator()(DataType_t const temperature) const
+    {
+        if (temperature < Tlo_) {
+            return LowerExtrapolation::extrapolate(temperature, *this);
+        } else if (temperature > Thi_) {
+            return UpperExtrapolation::extrapolate(temperature, *this);
+        } else {
+            return databox_.interpToReal(std::log(temperature));
+        }
+    }
+    SINGE_PORTABLE_FUNCTION constexpr void finalize()
+    {
+        databox_.finalize();
+    }
+};
+
+// ================================================================================================
+
+} // end namespace util
+} // end namespace singe
+
+#endif // ifndef SINGE_UTIL_DATABOXWRAPPER_HPP