tweaks

gridder_cxx.h

@@ -417,7 +417,7 @@ class ES_Kernel
         myassert(supp<opt_beta.size(), "bad support size");
         return opt_beta[supp];
         }
-      if (ofactor>=1.2)
+      if (ofactor>=1.175)
         {
         // empirical, but pretty accurate approximation
         static const array<double,16> betacorr{0,0,-0.51,-0.21,-0.1,-0.05,-0.025,-0.0125,0,0,0,0,0,0,0,0};
@@ -441,7 +441,7 @@ class ES_Kernel
           if (epssq>maxmaperr[i]) return i;
         myfail("requested epsilon too small - minimum is 1e-13");
         }
-      if (ofactor>=1.2)
+      if (ofactor>=1.175)
         {
         for (size_t w=2; w<16; ++w)
           {
@@ -632,7 +632,7 @@ class GridderConfig
       myassert(epsilon>0, "epsilon must be positive");
       myassert(pixsize_x>0, "pixsize_x must be positive");
       myassert(pixsize_y>0, "pixsize_y must be positive");
-      myassert(ofactor>=1.2, "oversampling factor smaller than 1.2");
+      myassert(ofactor>=1.175, "oversampling factor is too small");
 
       auto tmp = correction_factors(nu, ofactor, nx_dirty/2+1, supp, nthreads);
       cfu[nx_dirty/2]=tmp[0];