anchor.diff:  %% sample call sequence to get a tx trace:
   %% tex traces have to be relatively short, so paste all at once to the
   %% erlang shell.
  -%% api_tx:write("b", 1). trace_mpath:start(). api_tx:write("a", 1). trace_mpath:stop(). T = trace_mpath:get_trace(). trace_mpath:to_texfile(T, "trace.tex").
  +%% api_tx:write("b", 1). trace_mpath:start(). api_tx:write("a", 1). trace_mpath:stop(). timer:sleep(10). T = trace_mpath:get_trace(). trace_mpath:to_texfile(T, "trace.tex").
  +%%  P = pid_groups:find_a(trace_mpath). gen_component:bp_set_cond(P, fun(_,_) -> true end, mybp). api_tx:write("b", 1). trace_mpath:start(). api_tx:write("a", 1). trace_mpath:stop(). timer:sleep(1). gen_component:bp_del(P, mybp). gen_component:bp_cont(P). timer:sleep(10).  T = trace_mpath:get_trace(). trace_mpath:to_texfile(T, "trace.tex").
  +%% P = pid_groups:find_a(trace_mpath). gen_component:bp_set_cond(P, fun(_,_)-> true end, mybp). rbrcseq:qread(self(), "b"). receive _ -> ok end. trace_mpath:start(). rbrcseq:qread(self(), "a"). receive _ -> ok end. trace_mpath:stop(). gen_component:bp_del(P, mybp). gen_component:bp_cont(P). T = trace_mpath:get_trace(). trace_mpath:to_texfile(T, "trace.tex").
   
   -spec to_texfile(trace(), file:name()) -> ok | {error, file:posix() | badarg | terminated}.
   to_texfile(Trace, Filename) ->
  -    ScaleX = 30, %% 1 cm is ScaleX microseconds in the plot
  -    TicsFreq = 50, %% draw x-tics every TicsFreq microseconds
  +    ScaleX = 20, %% 1 cm is ScaleX microseconds in the plot
  +    TicsFreq = 20, %% draw x-tics every TicsFreq microseconds
   
       {ok, File} = file:open(Filename, [write]),
       io:format(File,
  
positive.code: -spec normalize_pidinfo(anypid()) -> pidinfo().
  normalize_pidinfo(Pid) ->
      case is_pid(Pid) of
          true -> {comm:make_global(Pid), pid_groups:group_and_name_of(Pid)};
          false ->
              case comm:is_valid(Pid) of
                  true ->
                      case comm:is_local(Pid) of
                          true -> {Pid,
                                   pid_groups:group_and_name_of(
                                     comm:make_local(Pid))};
                          false -> {Pid, non_local_pid_name_unknown}
                      end;
                  false -> %% already a pidinfo()
  
negative.code:         log_recv ->
              %% found a receive without a send?
              %% not yet implemented
              io:format("Found receive without send?~n"),
            _ = element(5, X),
              DrawTrace;
          log_info ->
              %% print info somewhere
  