code: @Override
      public Long getMinimumStart() {
          calculator();
          if (simple) {
              return v[0];
          } else {
              Weight minStart = cn.getMinimumStart();
              return minStart.isInfinity() ? null : minStart.value();
          }
      }
docs: /*
  (non-Javadoc)
  
  @see org.virginia.pbhs.parameters.Interval#getMinimumStart()