Add function which returns all effective uvws

nifty_gridder.cc

@@ -412,6 +412,24 @@ template<typename T> class Baselines
     np.array((nvis,), dtype=np.complex)
         The visibility data for the index array
     )""";
+
+    pyarr_c<T> ind2effectiveuvw(const pyarr_c<uint32_t> &idx_) const
+    {
+      checkArray(idx_, "idx", {0});
+      size_t nvis = size_t(idx_.shape(0));
+      auto idx = idx_.template unchecked<1>();
+      auto res_=makeArray<T>({nvis, 3});
+      auto res = res_.template mutable_unchecked<2>();
+      for (size_t i=0; i<nvis; i++)
+        {
+          auto uvw = effectiveCoord(idx(i));
+          res(i,0) = uvw.u;
+          res(i,1) = uvw.v;
+          res(i,2) = uvw.w;
+        }
+      return res_;
+    }
+
     template<typename T2> pyarr_c<T2> ms2vis(const pyarr<T2> &ms_,
       const pyarr_c<uint32_t> &idx_) const
       {
@@ -1528,6 +1546,7 @@ PYBIND11_MODULE(nifty_gridder, m)
     .def ("Nchannels",&Baselines<double>::Nchannels)
     .def ("ms2vis",&Baselines<double>::ms2vis<complex<double>>,
       Baselines<double>::ms2vis_DS, "ms"_a, "idx"_a)
+    .def ("ind2effectiveuvw",&Baselines<double>::ind2effectiveuvw, "idx"_a)
     .def ("vis2ms",&Baselines<double>::vis2ms<complex<double>>,
       Baselines<double>::vis2ms_DS, "vis"_a, "idx"_a, "ms_in"_a=None);
   py::class_<GridderConfig<double>> (m, "GridderConfig", GridderConfig_DS)