                                               db.reference_window_start.size());
 
         // compute the initial vcf range
-        uint2 vcf_range = make_uint2(vcf_start - db.reference_window_start.begin(),
-                                     vcf_start - db.reference_window_start.begin());
+        uint2 vcf_range;
 
         vcf_range.x = vcf_start - db.reference_window_start.begin();
         vcf_range.y = vcf_range.x;

        }

        // expand the start of the range backwards to find the first feature that overlaps with our alignment window
        while(vcf_range.x != 0 &&
              db.reference_window_start[vcf_range.x - 1] + db.alignment_window_len[vcf_range.x - 1] >= alignment_window.x)
        {
            vcf_range.x--;

        {
            loc_start = inside;
        } else {
            loc_start = right;
        }

