TimerOutput::get_summary_data() returns wrong type for n_calls

[marcfehling]

TimerOutput::get_summary_data() can get called with any option of TimerOutput::OutputData, but always returns the value as a double.

For TimerOutput::OutputData::n_calls this should be an unsigned int.

Do you have an idea for a nice way how to make this right? We can introduce a template parameter for this function which defaults to double, and then the user could specify the data type he wants.

[bangerth]

That's unnecessarily complicated. It's also not backward compatible unless you default the template argument to double. You could use std::variant<double,unsigned int> if necessary, though then you have to decide whether it should really be an unsigned int of perhaps something larger.

In practice, I cannot think of a different usage for this function than to just output the result. In that case, the return type doesn't matter.