From 31f696078cd57fe0a2dba5c2fe02c6917041700d Mon Sep 17 00:00:00 2001
From: Timothy Poon <timothy0626@gmail.com>
Date: Tue, 6 Jul 2021 16:03:52 +0100
Subject: [PATCH 1/3] Used parameter attribute to accommodate polynomial with
 different orders

---
 hyperspy/_components/polynomial.py | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/hyperspy/_components/polynomial.py b/hyperspy/_components/polynomial.py
index b0d4291cbf..3aac6c9b44 100644
--- a/hyperspy/_components/polynomial.py
+++ b/hyperspy/_components/polynomial.py
@@ -33,7 +33,7 @@ class Polynomial(Expression):
     """n-order polynomial component.
 
     Polynomial component consisting of order + 1 parameters.
-    The parameters are named "a" followed by the corresponding order, 
+    The parameters are named "a" followed by the corresponding order,
     i.e.
 
     .. math::
@@ -60,10 +60,10 @@ def __init__(self, order=2, module="numexpr", **kwargs):
             raise ValueError("Polynomial of order 0 is not supported.")
         coeff_list = ['{}'.format(o).zfill(len(list(str(order)))) for o in
                       range(order, -1, -1)]
-        expr = "+".join(["a{}*x**{}".format(c, o) for c, o in 
+        expr = "+".join(["a{}*x**{}".format(c, o) for c, o in
                          zip(coeff_list, range(order, -1, -1))])
         name = "{} order Polynomial".format(ordinal(order))
-        super().__init__(expression=expr, name=name, module=module, 
+        super().__init__(expression=expr, name=name, module=module,
              autodoc=False, **kwargs)
         self._id_name = "eab91275-88db-4855-917a-cdcbe7209592"
 
@@ -107,7 +107,7 @@ def estimate_parameters(self, signal, x1, x2, only_current=False):
                     para.value = estim
             return True
         else:
-            if self.a0.map is None:
+            if self.parameters[0].map is None:
                 self._create_arrays()
 
             nav_shape = signal.axes_manager._navigation_shape_in_array
@@ -142,7 +142,7 @@ def convert_to_polynomial(poly_dict):
     """
     _logger.info("Converting the polynomial to the new definition")
     poly_order = poly_dict['order']
-    coeff_list = ['{}'.format(o).zfill(len(list(str(poly_dict['order'])))) 
+    coeff_list = ['{}'.format(o).zfill(len(list(str(poly_dict['order']))))
                   for o in range(poly_dict['order'], -1, -1)]
     poly2_dict = dict(poly_dict)
     coefficient_dict = poly_dict['parameters'][0]

From 322fc97c97d11aa86a4f0f5e2a9cc2f69f9e02df Mon Sep 17 00:00:00 2001
From: Timothy Poon <timothy0626@gmail.com>
Date: Tue, 6 Jul 2021 16:29:48 +0100
Subject: [PATCH 2/3] Modified relevant test for higher order polynomial
 component

---
 hyperspy/tests/component/test_components.py | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/hyperspy/tests/component/test_components.py b/hyperspy/tests/component/test_components.py
index 446b722dfc..4d332e8e8e 100644
--- a/hyperspy/tests/component/test_components.py
+++ b/hyperspy/tests/component/test_components.py
@@ -308,16 +308,17 @@ def test_fitting(self):
         m_2d.multifit(iterpath='serpentine', grad='analytical')
         np.testing.assert_allclose(m_2d.red_chisq.data.sum(), 0.0, atol=1E-7)
 
+    @pytest.mark.parametrize(("order"), (2, 12))
     @pytest.mark.parametrize(("only_current", "binned"), TRUE_FALSE_2_TUPLE)
-    def test_estimate_parameters(self,  only_current, binned):
+    def test_estimate_parameters(self,  only_current, binned, order):
         self.m.signal.metadata.Signal.binned = binned
         s = self.m.as_signal()
         s.metadata.Signal.binned = binned
-        p = hs.model.components1D.Polynomial(order=2, legacy=False)
+        p = hs.model.components1D.Polynomial(order=order, legacy=False)
         p.estimate_parameters(s, None, None, only_current=only_current)
-        np.testing.assert_allclose(p.a2.value, 0.5)
-        np.testing.assert_allclose(p.a1.value, 2)
-        np.testing.assert_allclose(p.a0.value, 3)
+        np.testing.assert_allclose(p.parameters[2].value, 0.5)
+        np.testing.assert_allclose(p.parameters[1].value, 2)
+        np.testing.assert_allclose(p.parameters[0].value, 3)
 
     def test_zero_order(self):
         m = self.m_offset

From d85c486cd8a67c02fccda18adceb8a9665bbb612 Mon Sep 17 00:00:00 2001
From: Timothy Poon <timothy0626@gmail.com>
Date: Tue, 6 Jul 2021 21:57:28 +0100
Subject: [PATCH 3/3] Added changelog for #2790

---
 upcoming_changes/2790.bugfix.rst | 2 ++
 1 file changed, 2 insertions(+)
 create mode 100644 upcoming_changes/2790.bugfix.rst

diff --git a/upcoming_changes/2790.bugfix.rst b/upcoming_changes/2790.bugfix.rst
new file mode 100644
index 0000000000..3d72b9cb5a
--- /dev/null
+++ b/upcoming_changes/2790.bugfix.rst
@@ -0,0 +1,2 @@
+Method `estimate_parameters` in `Polynomial` component now supports order
+greater than 10.