21     setIfInInput(
name_, 
"name");
 helper functions for EinsplineSetBuilder 
PerParticleHamiltonianLoggerInput()=default
For this input class its valid with just its defaults. 
#define LAMBDA_setIfInInput
If tag is present in input_secution set its variable. 
void readXML(xmlNodePtr cur)
Read variable values (initialize) from XML input, call checkValid. 
PerParticleHamiltonianLoggerInputSection input_section_