Interp2d.icc

#include <isce3/math/complexOperations.h>
 
#include "Interp1d.h"
#include "detail/Interp1d.h"
#include "detail/SSOBuffer.h"
 
namespace isce3 { namespace core {
 
template<typename KernelType, typename DataType>
DataType interp2d(const Kernel<KernelType>& kernelx,
        const Kernel<KernelType>& kernely, const DataType* z, size_t nx,
        size_t stridex, size_t ny, size_t stridey, double x, double y,
        bool periodic)
{
    using namespace isce3::math::complex_operations;
 
    // Small-size optimization to avoid heap allocation.
    const int widthx = static_cast<int>(ceil(kernelx.width()));
    const int widthy = static_cast<int>(ceil(kernely.width()));
    detail::SSOBuffer<KernelType> coeffsx(widthx), coeffsy(widthy);
    detail::SSOBuffer<DataType> datax(widthx), datay(widthy);
 
    // Pre-compute (widthx + widthy) coefficients rather than calculating them
    // (widthx * widthy) times inside the loop.
    // In principle we could delay calculating coeffsy until after the loop, in
    // which case we'd only need a single coefficient buffer.  But we need lowy
    // which comes from the same API call, and we're probably okay on stack
    // space anyhow.
    long lowx = 0, lowy = 0;
    detail::interp1d_coeffs(kernelx, x, &lowx, coeffsx.data());
    detail::interp1d_coeffs(kernely, y, &lowy, coeffsy.data());
 
    // Do X interp at each Y index.
    for (int i_kernely = 0; i_kernely < widthy; ++i_kernely) {
        long i_datay = i_kernely + lowy;
        if (periodic)
            i_datay %= ny;
        if ((i_datay >= 0) and (i_datay < ny)) {
            const DataType* zi = &z[i_datay * stridey];
            const DataType* px = detail::get_contiguous_view_or_copy(
                    datax.data(), widthx, lowx, zi, nx, stridex, periodic);
            datay[i_kernely] = detail::inner_product(widthx, coeffsx.data(), px);
        } else {
            datay[i_kernely] = 0;
        }
    }
    // Do Y interp.
    return detail::inner_product(widthy, coeffsy.data(), datay.data());
}
 
}} // namespace isce3::core