Further protect users from mistakes in HX backward compat methods lea…

…ding to a zero divisor
NREL · May 13, 2024 · 1b8f688 · 1b8f688
1 parent 04636b4
commit 1b8f688
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Showing 2 changed files with 50 additions and 8 deletions.
diff --git a/src/model/HeatExchangerAirToAirSensibleAndLatent.cpp b/src/model/HeatExchangerAirToAirSensibleAndLatent.cpp
@@ -35,6 +35,8 @@
 // Remove when deprecated methods are removed
 #include "../utilities/core/DeprecatedHelpers.hpp"
 
+#include <limits>
+
 namespace openstudio {
 
 namespace model {
@@ -1026,8 +1028,13 @@ namespace model {
       return setCurveAt75(*curve_, sensibleEffectivenessat75HeatingAirFlow);
     }
 
-    auto tableLookup = makeTable(sensibleEffectivenessat75HeatingAirFlow, sensibleEffectivenessat100HeatingAirFlow(), model(),
-                                 fmt::format("{}_SensHeatEff", nameString()));
+    const auto val100 = sensibleEffectivenessat100HeatingAirFlow();
+    if (std::abs(val100) < std::numeric_limits<double>::min()) {
+      LOG_AND_THROW("Unable to set " << briefDescription()
+                                     << "'s Sensible Effectiveness at 75 Heating Air Flow because the value at 100 is zero and would lead to a "
+                                        "Normalization divisor equal to zero.");
+    }
+    auto tableLookup = makeTable(sensibleEffectivenessat75HeatingAirFlow, val100, model(), fmt::format("{}_SensHeatEff", nameString()));
     return setSensibleEffectivenessofHeatingAirFlowCurve(tableLookup);
   }
 
@@ -1038,8 +1045,13 @@ namespace model {
       return setCurveAt75(*curve_, latentEffectivenessat75HeatingAirFlow);
     }
 
-    auto tableLookup =
-      makeTable(latentEffectivenessat75HeatingAirFlow, latentEffectivenessat100HeatingAirFlow(), model(), fmt::format("{}_LatHeatEff", nameString()));
+    const auto val100 = latentEffectivenessat100HeatingAirFlow();
+    if (std::abs(val100) < std::numeric_limits<double>::min()) {
+      LOG_AND_THROW("Unable to set " << briefDescription()
+                                     << "'s Latent Effectiveness at 75 Heating Air Flow because the value at 100 is zero and would lead to a "
+                                        "Normalization divisor equal to zero.");
+    }
+    auto tableLookup = makeTable(latentEffectivenessat75HeatingAirFlow, val100, model(), fmt::format("{}_LatHeatEff", nameString()));
     return setLatentEffectivenessofHeatingAirFlowCurve(tableLookup);
   }
 
@@ -1050,8 +1062,13 @@ namespace model {
       return setCurveAt75(*curve_, sensibleEffectivenessat75CoolingAirFlow);
     }
 
-    auto tableLookup = makeTable(sensibleEffectivenessat75CoolingAirFlow, sensibleEffectivenessat100CoolingAirFlow(), model(),
-                                 fmt::format("{}_SensCoolEff", nameString()));
+    const auto val100 = sensibleEffectivenessat100CoolingAirFlow();
+    if (std::abs(val100) < std::numeric_limits<double>::min()) {
+      LOG_AND_THROW("Unable to set " << briefDescription()
+                                     << "'s Sensible Effectiveness at 75 Cooling Air Flow because the value at 100 is zero and would lead to a "
+                                        "Normalization divisor equal to zero.");
+    }
+    auto tableLookup = makeTable(sensibleEffectivenessat75CoolingAirFlow, val100, model(), fmt::format("{}_SensCoolEff", nameString()));
     return setSensibleEffectivenessofCoolingAirFlowCurve(tableLookup);
   }
 
@@ -1062,8 +1079,13 @@ namespace model {
       return setCurveAt75(*curve_, latentEffectivenessat75CoolingAirFlow);
     }
 
-    auto tableLookup =
-      makeTable(latentEffectivenessat75CoolingAirFlow, latentEffectivenessat100CoolingAirFlow(), model(), fmt::format("{}_LatCoolEff", nameString()));
+    const auto val100 = latentEffectivenessat100CoolingAirFlow();
+    if (std::abs(val100) < std::numeric_limits<double>::min()) {
+      LOG_AND_THROW("Unable to set " << briefDescription()
+                                     << "'s Latent Effectiveness at 75 Cooling Air Flow because the value at 100 is zero and would lead to a "
+                                        "Normalization divisor equal to zero.");
+    }
+    auto tableLookup = makeTable(latentEffectivenessat75CoolingAirFlow, val100, model(), fmt::format("{}_LatCoolEff", nameString()));
     return setLatentEffectivenessofCoolingAirFlowCurve(tableLookup);
   }
 

diff --git a/src/model/test/HeatExchangerAirToAirSensibleAndLatent_GTest.cpp b/src/model/test/HeatExchangerAirToAirSensibleAndLatent_GTest.cpp
@@ -401,6 +401,26 @@ TEST_F(ModelFixture, HeatExchangerAirToAirSensibleAndLatent_Deprecated75Effectiv
     EXPECT_TRUE(hx.setLatentEffectivenessat75CoolingAirFlow(val2));
     EXPECT_DOUBLE_EQ(val2, hx.latentEffectivenessat75CoolingAirFlow());
   }
+
+  // Ensure we protect users against dumb issues that lead to a normalization divisor of zero
+  {
+    // Ensure no curves assigned for now
+    hx.resetSensibleEffectivenessofHeatingAirFlowCurve();
+    hx.resetLatentEffectivenessofHeatingAirFlowCurve();
+    hx.resetSensibleEffectivenessofCoolingAirFlowCurve();
+    hx.resetLatentEffectivenessofCoolingAirFlowCurve();
+
+    // IMHO this doesn't make sense (IDD should be `\minimum> 0.0`), but the E+ IDD and OS IDD have always allowed it, so leaving it untouched
+    EXPECT_TRUE(hx.setSensibleEffectivenessat100HeatingAirFlow(0.0));
+    EXPECT_TRUE(hx.setLatentEffectivenessat100HeatingAirFlow(0.0));
+    EXPECT_TRUE(hx.setSensibleEffectivenessat100CoolingAirFlow(0.0));
+    EXPECT_TRUE(hx.setLatentEffectivenessat100CoolingAirFlow(0.0));
+
+    EXPECT_ANY_THROW(hx.setSensibleEffectivenessat75HeatingAirFlow(0.5));
+    EXPECT_ANY_THROW(hx.setLatentEffectivenessat75HeatingAirFlow(0.5));
+    EXPECT_ANY_THROW(hx.setSensibleEffectivenessat75CoolingAirFlow(0.5));
+    EXPECT_ANY_THROW(hx.setLatentEffectivenessat75CoolingAirFlow(0.5));
+  }
 }
 
 TEST_F(ModelFixture, HeatExchangerAirToAirSensibleAndLatent_assignHistoricalEffectivenessCurves) {