    for (SizeT k = 0; k < ny; ++k) {
      for (SizeT j = 0; j < nx; ++j) { //nb output points
        vres = &(res[ncontiguous * (k * nx + j) ]);
        x = xx[j];
        if (x < 0) {
          xi[0] = 0; xi[1] = 0;
        } else if (x >= n1-1 ) {
          xi[0] = n1-1; xi[1] = n1-1;
        } else {
          ix = floor(x);
          xi[0] = ix;
          xi[1] = ix + 1;
        }
        y = yy[k];
        if (y < 0) {
          yi[0] = 0; yi[1] = 0;
        } else if (y >= n2-1 ) {
          yi[0] = n2-1; yi[1] = n2-1;
        } else {
          iy = floor(y);
          yi[0] = iy;
          yi[1] = iy + 1;
        }
        dx = (x - xi[0]);
        dy = (y - yi[0]);
        vx0 = &(array[ncontiguous * (yi[0] * n1 + xi[0])]);
        vx1 = &(array[ncontiguous * (yi[0] * n1 + xi[1])]);
        vy0 = &(array[ncontiguous * (yi[1] * n1 + xi[0])]);
        vy1 = &(array[ncontiguous * (yi[1] * n1 + xi[1])]);
        for (SizeT i = 0; i < ncontiguous; ++i) {
          double dxdy=dx*dy;
          double c0=(1-dy-dx+dxdy);
          double c1=(dy-dxdy);
          double c2=(dx-dxdy);
          vres[i] = vx0[i] * c0 + vy0[i] * c1 + vx1[i] * c2 + vy1[i]*dxdy;
        }
      }
    }