Guard against bad dropout rate

Author: milancurcic

src/nf/nf_layer_constructors_submodule.f90

@@ -69,6 +69,8 @@ end function dense
   module function dropout(rate) result(res)
     real, intent(in) :: rate
     type(layer) :: res
+    if (rate < 0 .or. rate > 1) &
+      error stop 'rate must be between 0 and 1 in a dropout layer'
     res % name = 'dropout'
     allocate(res % p, source=dropout_layer(rate))
   end function dropout
@@ -81,7 +83,6 @@ module function flatten() result(res)
   end function flatten
 
 
-
   module function input1d(layer_size) result(res)
     integer, intent(in) :: layer_size
     type(layer) :: res