Merge pull request #142 from fjosw/feat/root_of_multi_parameter_functions

Root of multi parameter functions

pyerrors/roots.py

@@ -27,15 +27,17 @@ def find_root(d, func, guess=1.0, **kwargs):
     Obs
         `Obs` valued root of the function.
     '''
-    root = scipy.optimize.fsolve(func, guess, d.value)
+    d_val = np.vectorize(lambda x: x.value)(np.array(d))
+
+    root = scipy.optimize.fsolve(func, guess, d_val)
 
     # Error propagation as detailed in arXiv:1809.01289
-    dx = jacobian(func)(root[0], d.value)
+    dx = jacobian(func)(root[0], d_val)
     try:
-        da = jacobian(lambda u, v: func(v, u))(d.value, root[0])
+        da = jacobian(lambda u, v: func(v, u))(d_val, root[0])
     except TypeError:
         raise Exception("It is required to use autograd.numpy instead of numpy within root functions, see the documentation for details.") from None
     deriv = - da / dx
-
-    res = derived_observable(lambda x, **kwargs: (x[0] + np.finfo(np.float64).eps) / (d.value + np.finfo(np.float64).eps) * root[0], [d], man_grad=[deriv])
+    res = derived_observable(lambda x, **kwargs: (x[0] + np.finfo(np.float64).eps) / (np.array(d).reshape(-1)[0].value + np.finfo(np.float64).eps) * root[0],
+                             np.array(d).reshape(-1), man_grad=np.array(deriv).reshape(-1))
     return res

tests/roots_test.py

@@ -42,3 +42,13 @@ def test_root_no_autograd():
 
     with pytest.raises(Exception):
         my_root = pe.roots.find_root(my_obs, root_function)
+
+
+def test_root_multi_parameter():
+    o1 = pe.pseudo_Obs(1.1, 0.1, "test")
+    o2 = pe.pseudo_Obs(1.3, 0.12, "test")
+
+    f2 = lambda x, d: d[0] + d[1] * x
+
+    assert f2(-o1 / o2, [o1, o2]) == 0
+    assert pe.find_root([o1, o2], f2) == -o1 / o2