Merge pull request #35 from licode/expressModel

Express model

vttools/tests/test_fitting.py

@@ -43,7 +43,7 @@
 from skxray.testing.decorators import known_fail_if
 from vttools.to_wrap.fitting import (gaussian_model, lorentzian_model,
                                      lorentzian2_model, quadratic_model,
-                                     fit_engine)
+                                     fit_engine, fit_engine_list, expression_model)
 from nose.tools import (assert_equal, assert_true, raises)
 
 
@@ -114,6 +114,7 @@ def test_lorentzian2_fit():
     fitted_val = (out['area'], out['center'], out['sigma'])
     assert_array_almost_equal(true_val, fitted_val)
 
+
 def test_quadratic_fit():
     x = np.arange(-1, 1, .01)
     a = 1
@@ -133,3 +134,31 @@ def test_quadratic_fit():
     out = result.values
     fitted_val = (out['a'], out['b'], out['c'])
     assert_array_almost_equal(true_val, fitted_val)
+
+
+def test_fit_engine_list():
+    a = 1
+    b = 2
+    c = 3
+    m = quadratic_model('',
+                        a, 'free', [-1, 1],
+                        b, 'free', [-1, 1],
+                        c, 'free', [-1, 1])
+    x = np.arange(-1, 1, 0.01)
+    y = x**2 + 1
+
+    datav = [(x, y), (x, y+2)]
+    out = fit_engine_list(m, datav)
+    assert_equal(len(out), 2)
+
+
+def test_expression_model():
+
+    inputv = 'exp(-a*x)'
+
+    x = np.arange(-1, 1, 0.01)
+    y = np.exp(-x)
+
+    mod = expression_model(inputv)
+    out = mod.fit(y, x=x, a=0.1)
+    assert_equal(1, out.values['a'])

vttools/to_wrap/fitting.py

@@ -34,7 +34,8 @@
 ########################################################################
 import sys
 from skxray.fitting.api import (QuadraticModel, GaussianModel,
-                                 LorentzianModel, Lorentzian2Model)
+                                LorentzianModel, Lorentzian2Model,
+                                ExpressionModel)
 
 import logging
 logger = logging.getLogger(__name__)
@@ -150,6 +151,24 @@ def fit_engine_list(g, data):
     return result_list
 
 
+def expression_model(model_exp):
+    """
+    This function creates a Model from a user-supplied expression.
+
+    Parameters
+    ----------
+    model_exp : str
+        expression of the model
+
+    Returns
+    -------
+    mod : array_like
+        object of fitting results
+    """
+    mod = ExpressionModel(model_exp)
+    return mod
+
+
 def set_range(model_name,
               parameter_name, parameter_value,
               parameter_vary, parameter_range):
@@ -265,9 +284,3 @@ def inner(prefix, amplitude, amplitude_vary, amplitude_range,
     func_name.amplitude_vary = ['fixed', 'free', 'bounded']
     func_name.center_vary = ['fixed', 'free', 'bounded']
     func_name.sigma_vary = ['fixed', 'free', 'bounded']
-
-
-function_list = [fit_engine, fit_engine_list, quadratic_model]
-
-for func_name in function_list:
-    setattr(mod, func_name.__name__, func_name)

vttools/vtmods/import_lists/modules.yaml

@@ -74,6 +74,9 @@ autowrap_func:
 - func_name: fit_engine_list
   module_path: vttools.to_wrap.fitting
   namespace: fitting
+- func_name: expression_model
+  module_path: vttools.to_wrap.fitting
+  namespace: fitting
 # CALIBRATION
 - func_name: refine_center
   module_path: skxray.calibration