GetTDewPointFromVapPres: add simple test to check convergence (#27)

tests/js/test_psychrolib_si.js

@@ -91,6 +91,14 @@ it('test_VapPres_TDewPoint', function () {
     expect(psyjs.GetTDewPointFromVapPres(60.0, VapPres)).to.be.closeTo(50.0, 0.001)
 });
 
+// Test of relationships between wet bulb temperature and relative humidity
+// This test was known to cause a convergence issue in GetTDewPointFromVapPres
+// in versions of PsychroLib <= 2.0.0
+it('test_TWetBulb_RelHum', function () {
+    var TWetBulb = psyjs.GetTWetBulbFromRelHum(7, 0.61, 100000)
+    checkRelDiff(TWetBulb, 3.92667433781955, 0.001)
+});
+
 // Test of relationships between humidity ratio and vapour pressure
 it('test_HumRatio_VapPres', function () {
         var HumRatio = psyjs.GetHumRatioFromVapPres(3169.7, 95461)          // conditions at 25 C, std atm pressure at 500 m

tests/test_psychrolib_si.py

@@ -1,6 +1,7 @@
 # Copyright (c) 2018 D. Thevenard and D. Meyer. Licensed under the MIT License.
 # Test of PsychroLib in SI units for Python, C, and Fortran.
 
+import numpy as np
 import pytest
 
 pytestmark = pytest.mark.usefixtures('SetUnitSystem_SI')
@@ -68,6 +69,24 @@ def test_VapPres_TDewPoint(psy):
     VapPres = psy.GetVapPresFromTDewPoint(50.0)
     assert psy.GetTDewPointFromVapPres(60.0, VapPres) == pytest.approx(50.0, abs = 0.001)
 
+# Test of relationships between wet bulb temperature and relative humidity
+# This test was known to cause a convergence issue in GetTDewPointFromVapPres
+# in versions of PsychroLib <= 2.0.0
+def test_TWetBulb_RelHum(psy):
+    TWetBulb = psy.GetTWetBulbFromRelHum(7, 0.61, 100000)
+    assert TWetBulb == pytest.approx(3.92667433781955, rel = 0.001)
+
+# Test that the NR in GetTDewPointFromVapPres converges.
+# This test was known problem in versions of PsychroLib <= 2.0.0
+# def test_GetTDewPointFromVapPres_convergence(psy):
+#     TDryBulb = np.arange(30, 40, 0.1)
+#     RelHum = np.arange(0.1, 0.9, 0.01)
+#     Pressure = np.arange(101010, 120000)
+#     for T in TDryBulb:
+#         for RH in RelHum:
+#             for p in Pressure:
+#                 psy.GetTWetBulbFromRelHum(T, RH, p)
+
 # Test of relationships between humidity ratio and vapour pressure
 # Humidity ratio values to test against are calculated with Excel
 def test_HumRatio_VapPres(psy):

tests/vba/test_psychrolib_si.bas

@@ -126,6 +126,14 @@ Sub test_VapPres_TDewPoint()
   Call TestExpression("GetTDewPointFromVapPres", GetTDewPointFromVapPres(60#, VapPres), 50#, abst:=0.001)
 End Sub
 
+' Test of relationships between wet bulb temperature and relative humidity
+' This test was known to cause a convergence issue in GetTDewPointFromVapPres
+' in versions of PsychroLib <= 2.0.0
+Sub test_TWetBulb_RelHum()
+TWetBulb = GetTWetBulbFromRelHum(7, 0.61, 100000)
+Call TestExpression("GetTWetBulbFromRelHum", TWetBulb, 3.92667433781955, relt:=0.001)
+End Sub
+
 ' Test of relationships between humidity ratio and vapour pressure
 ' Humidity ratio values to test against are calculated with Excel
 Sub test_HumRatio_VapPres()