static void
iter_<%=c_func%>(na_loop_t *const lp)
{
    size_t   n, i;
    char    *p1, *p2;
    ssize_t  s1, s2;
    ssize_t  x1;
    size_t   y1;
    double   y2;
    <%=struct%> *w = (<%=struct%>*)(lp->opt_ptr);

    INIT_COUNTER(lp, n);
    INIT_PTR(lp, 0, p1, s1);
    INIT_PTR(lp, 1, p2, s2);

    for (i=0; i<n; i++) {
        GET_DATA_STRIDE(p1,s1,ssize_t,x1);
        if (x1 < 0) {
            y1 = x1 + w->n;
        } else {
            y1 = x1;
        }
        y2 = <%=func_name%>(<%=get(:postpose) ? "y1,w" : "w,y1"%>);
        SET_DATA_STRIDE(p2,s2,double,y2);
    }
}
#undef FUNC

/*
  @overload <%=name%>(<%=args[1][1]%>)
  @param  [Int32/64]  <%=args[1][1]%>
  @return [<%=class_name%>]  self

  <%= description %>
*/
static VALUE
<%=c_func(1)%>(VALUE self, VALUE v1)
{
    <%=struct%> *w;
    ndfunc_arg_in_t ain[1] = {{cSSZ,0}};
    ndfunc_arg_out_t aout[1] = {{cDF,0}};
    ndfunc_t ndf = {iter_<%=c_func%>, STRIDE_LOOP|NDF_EXTRACT, 1,1, ain,aout};

    TypedData_Get_Struct(self, <%=struct%>, &<%=data_type_var%>, w);

    return na_ndloop3(&ndf, w, 1, v1);
}