Do not calculate hv if length is 1 or less (#35)

Author: jbussemaker

sb_arch_opt/__init__.py

@@ -1 +1 @@
-__version__ = '1.6.0'
+__version__ = '1.6.1'

sb_arch_opt/algo/pymoo_interface/metrics.py

@@ -123,6 +123,9 @@ def do(self, f, *args, **kwargs):
         if f.ndim == 1:
             f = f[None, :]
 
+        if len(f) <= 1:
+            return 0.
+
         if self.ref_point is None:
             f_invalid = np.any(np.isinf(f) | np.isnan(f), axis=1)
             f_valid = f[~f_invalid, :]