more tweaks

gridder_cxx.h

@@ -530,7 +530,7 @@ class GridderConfig
     double beta;
     vector<double> cfu, cfv;
     size_t nthreads;
-//    double ushift, vshift;
+    double ushift, vshift;
     int maxiu0, maxiv0;
 
     complex<double> wscreen(double x, double y, double w, bool adjoint) const
@@ -554,7 +554,7 @@ class GridderConfig
         nu(max(2*nsafe,2*nx_dirty)), nv(max(2*nsafe,2*ny_dirty)),
         beta(2.3*supp),
         cfu(nx_dirty), cfv(ny_dirty), nthreads(nthreads_),
-//        ushift(-supp*0.5+1), vshift(-supp*0.5+1),
+        ushift(supp*(-0.5)+1+nu), vshift(supp*(-0.5)+1+nv),
         maxiu0((nu+nsafe)-supp), maxiv0((nv+nsafe)-supp)
       {
       myassert((nx_dirty&1)==0, "nx_dirty must be even");
@@ -673,12 +673,10 @@ class GridderConfig
 
     void getpix(double u_in, double v_in, double &u, double &v, int &iu0, int &iv0) const
       {
-      u=fmod1(u_in*psx)*nu,
-      iu0 = int(u-supp*0.5 + 1 + nu) - nu;
-      iu0 = min(iu0, maxiu0);
+      u=fmod1(u_in*psx)*nu;
+      iu0 = min(int(u+ushift)-int(nu), maxiu0);
       v=fmod1(v_in*psy)*nv;
-      iv0 = int(v-supp*0.5 + 1 + nv) - nv;
-      iv0 = min(iv0, maxiv0);
+      iv0 = min(int(v+vshift)-int(nv), maxiv0);
       }
 
     template<typename T> void apply_wscreen(const const_mav<complex<T>,2> &dirty,

nifty_gridder.cc

@@ -587,9 +587,9 @@ template<typename T> pyarr<complex<T>> Pygrid2vis_c(
   auto wgt2 = make_const_mav<1>(wgt);
   auto res = makeArray<complex<T>>({nvis});
   auto vis = make_mav<1>(res);
-  vis.fill(0);
   {
   py::gil_scoped_release release;
+  vis.fill(0);
   grid2vis_c<T>(baselines, gconf, idx2, grid2, vis, wgt2);
   }
   return res;

test.py

@@ -102,7 +102,7 @@ def test_adjointness_ms2dirty(nxdirty, nydirty, nrow, nchan, epsilon, singleprec
         if wgt is not None:
             wgt = wgt.astype("f4")
     dirty2 = ng.ms2dirty(uvw, freq, ms, wgt, nxdirty, nydirty, pixsizex,
-                         pixsizey, epsilon, wstacking, nthreads, 2).astype("f8")
+                         pixsizey, epsilon, wstacking, nthreads, 0).astype("f8")
     ms2 = ng.dirty2ms(uvw, freq, dirty, wgt, pixsizex, pixsizey, epsilon,
                       wstacking, nthreads, 0).astype("c16")
     tol = 5e-5 if singleprec else 5e-13