Change asymdecrease3 to a yet preferable form.

tests/test_fitting.py

@@ -249,8 +249,8 @@ def test_fit_asymdecrease3(self):
         # Check whether the logarithmic square fit worked correctly.
         dist1 = fit.mul_var_dist.distributions[1]
         self.assertAlmostEqual(dist1.shape.a, 0, delta=0.1) # Should be about 0
-        self.assertAlmostEqual(dist1.shape.b, 0.35, delta=0.5) # Should be about 0.35
-        self.assertAlmostEqual(np.abs(dist1.shape.c), 2.5, delta=2) # Should be about 2.5
+        self.assertAlmostEqual(dist1.shape.b, 0.35, delta=0.4) # Should be about 0.35
+        self.assertAlmostEqual(np.abs(dist1.shape.c), 0.45, delta=0.2) # Should be about 0.45
         self.assertAlmostEquals(dist1.shape(0), 0.35, delta=0.2) # Should be about 0.35
 
     def test_min_number_datapoints_for_fit(self):

tests/test_params.py

@@ -70,7 +70,7 @@ def test_FunctionParam_asymdecrease3(self):
         """
 
         test_func = FunctionParam('asymdecrease3', 1, 4, 3)
-        self.assertEqual(test_func._value(0), 2)
+        self.assertEqual(test_func._value(0), 5)
         self.assertEqual(test_func.func_name, 'asymdecrease3')
         self.assertEqual(str(test_func)[0:1], '1')
 

viroconcom/fitting.py

@@ -55,7 +55,7 @@ def _powerdecrease3(x, a, b, c):
 
 # 3-parameter function that asymptotically decreases (a dependence function).
 def _asymdecrease3(x, a, b, c):
-    return a + b / (1 + x + np.abs(c))
+    return a + b / (1 + c * x)
 
 
 # A 4-parameter logististics function (a dependence function).
@@ -565,8 +565,7 @@ def __init__(self, samples, dist_descriptions, timeout=None):
             - :exp3: :math:`a + b * e^{x * c}`
             - :lnsquare2: :math:`ln[a + b * sqrt(x / 9.81)`
             - :powerdecrease3: :math:`a + 1 / (x + b)^c`
-            - :asymdecrease3: :math:`a + b / (1 + x + |c|)`
-            - :asymdecrease3: :math:`a + 1 / (b * (x + c))`
+            - :asymdecrease3: :math:`a + b / (1 + c * x)`
             - :logistics4: :math:`a + b / [1 + e^{-c * (x - d)}]`
             - remark : in case of Lognormal_SigmaMu it is (sigma, None, mu)
 

viroconcom/params.py

@@ -85,7 +85,7 @@ def __init__(self, func_name, a, b, c, d=None,
                 :exp3: :math:`a + b * e^{x * c}`
                 :lnsquare2: :math:`\ln[a + b * \sqrt(x / 9.81)`
                 :powerdecrease3: :math:`a + 1 / (x + b)^c`
-                :asymdecrease3: :math:`a + b / (1 + x + |c|)`
+                :asymdecrease3: :math:`a + b / (1 + c * x)`
                 :logistics4: :math:`a + b / [1 + e^{-c * (x - d)}]`
         a,b,c : float
             The function parameters.
@@ -165,7 +165,7 @@ def _powerdecrease3(self, x):
 
     # A 3-parameter function that asymptotically decreases (a dependence function).
     def _asymdecrease3(self, x):
-        return self.a + self.b / (1 +  x + np.abs(self.c))
+        return self.a + self.b / (1 + self.c * x)
 
     # A 4-parameter logististics function (a dependence function).
     def _logistics4(self, x, a=None, b=None, c=None, d=None):
@@ -199,7 +199,7 @@ def __str__(self):
                                ")^" + str(self.c)
         elif self.func_name == "asymdecrease3":
             function_string = "" + str(self.a) + " + " + str(self.b) + \
-                               "/ (1 + x + |" + str(self.c) + "|)"
+                               "/ (1 + " + str(self.c) + " * x)"
         elif self.func_name == "logistics4":
             function_string = "" + str(self.a) + " + " + str(self.b) + \
                               " / {1 + e^[-" + str(self.c) + \

viroconcom/version.py

@@ -1 +1 @@
-__version__ = '1.3.4'
+__version__ = '1.3.5'