Example #1
0
    def setUp(self):
        self.md = (gr.Model() >> gr.cp_function(
            fun=lambda x: x, var=1, out=1, runtime=1) >>
                   gr.cp_marginals(x0={
                       "dist": "uniform",
                       "loc": 0,
                       "scale": 1
                   }) >> gr.cp_copula_independence())

        self.md_2d = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[0], var=2, out=1) >> gr.cp_marginals(
                x0={
                    "dist": "uniform",
                    "loc": 0,
                    "scale": 1
                },
                x1={
                    "dist": "uniform",
                    "loc": 0,
                    "scale": 1
                },
            ) >> gr.cp_copula_independence())

        self.md_mixed = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[0] + x[1], var=2,
            out=1) >> gr.cp_bounds(x0=(-1, +1)) >> gr.cp_marginals(x1={
                "dist": "uniform",
                "loc": 0,
                "scale": 1
            }, ) >> gr.cp_copula_independence())
Example #2
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    def setUp(self):
        ## Smooth model
        self.md_smooth = (gr.Model() >> gr.cp_function(
            fun=lambda x: [x, x + 1], var=["x"], out=["y", "z"]) >>
                          gr.cp_marginals(x={
                              "dist": "uniform",
                              "loc": 0,
                              "scale": 2
                          }) >> gr.cp_copula_independence())

        self.df_smooth = self.md_smooth >> gr.ev_df(
            df=pd.DataFrame(dict(x=[0, 1, 2])))

        ## Tree model
        self.md_tree = (gr.Model() >> gr.cp_function(
            fun=lambda x: [0, x < 5], var=["x"], out=["y", "z"]) >>
                        gr.cp_marginals(x={
                            "dist": "uniform",
                            "loc": 0,
                            "scale": 2
                        }) >> gr.cp_copula_independence())

        self.df_tree = self.md_tree >> gr.ev_df(
            df=pd.DataFrame(dict(x=np.linspace(0, 10, num=8))))

        ## Cluster model
        self.df_cluster = pd.DataFrame(
            dict(
                x=[0.1, 0.2, 0.3, 0.4, 1.1, 1.2, 1.3, 1.4],
                y=[0.3, 0.2, 0.1, 0.0, 1.3, 1.2, 1.1, 1.0],
                c=[0, 0, 0, 0, 1, 1, 1, 1],
            ))
Example #3
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    def test_opt(self):
        # invariant checks
        self.inv_test.md_arg(gr.eval_min, df_arg="df_start")
        self.inv_test.df_arg(gr.eval_min, df_arg="df_start", acc_none="always")

        md_bowl = (gr.Model("Constrained bowl") >> gr.cp_function(
            fun=lambda x: x[0]**2 + x[1]**2,
            var=["x", "y"],
            out=["f"],
        ) >> gr.cp_function(
            fun=lambda x: (x[0] + x[1] + 1),
            var=["x", "y"],
            out=["g1"],
        ) >> gr.cp_function(
            fun=lambda x: -(-x[0] + x[1] - np.sqrt(2 / 10)),
            var=["x", "y"],
            out=["g2"],
        ) >> gr.cp_bounds(
            x=(-1, +1),
            y=(-1, +1),
        ))

        df_res = md_bowl >> gr.ev_min(
            out_min="f",
            out_geq=["g1"],
            out_leq=["g2"],
        )

        # Check result
        self.assertTrue(abs(df_res.x[0] + np.sqrt(1 / 20)) < 1e-6)
        self.assertTrue(abs(df_res.y[0] - np.sqrt(1 / 20)) < 1e-6)

        # Check errors for violated invariants
        with self.assertRaises(ValueError):
            gr.eval_min(md_bowl, out_min="FALSE")
        with self.assertRaises(ValueError):
            gr.eval_min(md_bowl, out_min="f", out_geq=["FALSE"])
        with self.assertRaises(ValueError):
            gr.eval_min(md_bowl, out_min="f", out_eq=["FALSE"])

        # Test multiple restarts
        df_multi = gr.eval_min(
            md_bowl,
            out_min="f",
            out_geq=["g1"],
            out_leq=["g2"],
            n_restart=2,
        )
        self.assertTrue(df_multi.shape[0] == 2)
Example #4
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    def test_grad_fd(self):
        """Checks the FD code
        """
        ## Accuracy
        df_grad = gr.eval_grad_fd(
            self.model_2d, df_base=self.df_2d_nominal, append=False
        )

        self.assertTrue(np.allclose(df_grad[self.df_2d_grad.columns], self.df_2d_grad))

        ## Subset
        df_grad_sub = gr.eval_grad_fd(
            self.model_2d, df_base=self.df_2d_nominal, var=["x"], append=False
        )

        self.assertTrue(set(df_grad_sub.columns) == set(["Df_Dx", "Dg_Dx"]))

        ## Flags
        md_test = (
            gr.Model()
            >> gr.cp_function(fun=lambda x: x[0] + x[1] ** 2, var=2, out=1)
            >> gr.cp_marginals(x0={"dist": "norm", "loc": 0, "scale": 1})
        )
        df_base = pd.DataFrame(dict(x0=[0, 1], x1=[0, 1]))
        ## Multiple base points
        df_true = pd.DataFrame(dict(Dy0_Dx0=[1, 1], Dy0_Dx1=[0, 2]))

        df_rand = gr.eval_grad_fd(md_test, df_base=df_base, var="rand", append=False)
        self.assertTrue(gr.df_equal(df_true[["Dy0_Dx0"]], df_rand, close=True))

        df_det = gr.eval_grad_fd(md_test, df_base=df_base, var="det", append=False)
        self.assertTrue(gr.df_equal(df_true[["Dy0_Dx1"]], df_det, close=True))
Example #5
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 def setUp(self):
     self.md = (gr.Model() >> gr.cp_function(
         fun=lambda x: x,
         var=["x"],
         out=["y"],
     ) >> gr.cp_marginals(x=dict(dist="norm", loc=0, scale=1)) >>
                gr.cp_copula_independence())
Example #6
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 def __init__(self):
     """Setup necessary values"""
     self.md = (gr.Model() >> gr.cp_function(
         fun=lambda x: x, var=1, out=1, runtime=1))
     self.md_var_det = self.md >> gr.cp_bounds(x1=(0, 1))
     self.df = pd.DataFrame(data={"x": [0.0], "y": [0.5]})
     # declare tests
     self.type_tests = [(1, 2), 2, [1, 8]]
Example #7
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    def test_nls(self):
        ## Setup
        md_feat = (
            gr.Model()
            >> gr.cp_function(fun=lambda x: x[0] * x[1] + x[2], var=3, out=1,)
            >> gr.cp_bounds(x0=[-1, +1], x2=[0, 0])
            >> gr.cp_marginals(x1=dict(dist="norm", loc=0, scale=1))
        )

        md_const = (
            gr.Model()
            >> gr.cp_function(fun=lambda x: x[0], var=1, out=1)
            >> gr.cp_bounds(x0=(-1, +1))
        )

        df_response = md_feat >> gr.ev_df(
            df=gr.df_make(x0=0.1, x1=[-1, -0.5, +0, +0.5, +1], x2=0)
        )
        df_data = df_response[["x1", "y0"]]

        ## Model with features
        df_true = gr.df_make(x0=0.1)
        df_fit = md_feat >> gr.ev_nls(df_data=df_data, append=False)

        pd.testing.assert_frame_equal(
            df_fit,
            df_true,
            check_exact=False,
            check_dtype=False,
            check_column_type=False,
        )
        ## Fitting synonym
        md_feat_fit = df_data >> gr.ft_nls(md=md_feat, verbose=False)
        self.assertTrue(set(md_feat_fit.var) == set(["x1", "x2"]))

        ## Constant model
        df_const = gr.df_make(x0=0)
        df_fit = md_const >> gr.ev_nls(df_data=gr.df_make(y0=[-1, 0, +1]))

        pd.testing.assert_frame_equal(
            df_fit,
            df_const,
            check_exact=False,
            check_dtype=False,
            check_column_type=False,
        )
Example #8
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    def test_drop_out(self):
        """Checks that output column names are properly dropped"""
        md = gr.Model() >> gr.cp_function(lambda x: x[0] + 1, var=1, out=1)
        df_in = gr.df_make(x0=[0, 1, 2], y0=[0, 1, 2])
        df_true = gr.df_make(x0=[0, 1, 2], y0=[1, 2, 3])

        df_res = md >> gr.ev_df(df=df_in)

        self.assertTrue(gr.df_equal(df_res, df_true, close=True))
Example #9
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    def test_dag(self):
        md = (gr.Model("model") >> gr.cp_function(lambda x: x, var=1, out=1) >>
              gr.cp_function(lambda x: x[0] + x[1], var=["x0", "y0"], out=1))

        G_true = nx.DiGraph()
        G_true.add_edge("(var)", "f0", label="{}".format({"x0"}))
        G_true.add_edge("f0", "(out)", label="{}".format({"y0"}))
        G_true.add_edge("(var)", "f1", label="{}".format({"x0"}))
        G_true.add_edge("f0", "f1", label="{}".format({"y0"}))
        G_true.add_edge("f1", "(out)", label="{}".format({"y1"}))
        nx.set_node_attributes(G_true, "model", "parent")

        self.assertTrue(
            nx.is_isomorphic(
                md.make_dag(),
                G_true,
                node_match=lambda u, v: u == v,
                edge_match=lambda u, v: u == v,
            ))
Example #10
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    def setUp(self):
        self.md = models.make_test()

        self.md_mixed = (
            gr.Model()
            >> gr.cp_function(fun=lambda x: x[0], var=3, out=1)
            >> gr.cp_bounds(x2=(0, 1))
            >> gr.cp_marginals(
                x0={"dist": "uniform", "loc": 0, "scale": 1},
                x1={"dist": "uniform", "loc": 0, "scale": 1},
            )
            >> gr.cp_copula_independence()
        )
Example #11
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 def setUp(self):
     ## Linear limit state w/ MPP off initial guess
     self.beta_true = 3
     self.md = (
         gr.Model()
         >> gr.cp_function(
             fun=lambda x: self.beta_true * 2 - x[0] - np.sqrt(3) * x[1],
             var=2,
             out=["g"],
         )
         >> gr.cp_marginals(
             x0=dict(dist="norm", loc=0, scale=1, sign=1),
             x1=dict(dist="norm", loc=0, scale=1, sign=1),
         )
         >> gr.cp_copula_independence()
     )
Example #12
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    def test_var_outer(self):
        ## Test pass-throughs
        df_test = pd.DataFrame(dict(x0=[0]))
        md_no_rand = gr.Model() >> gr.cp_function(
            fun=lambda x: x, var=1, out=1)
        md_no_rand.var_outer(pd.DataFrame(), df_det="nom")

        md_no_det = md_no_rand >> gr.cp_marginals(x0={
            "dist": "uniform",
            "loc": 0,
            "scale": 1
        })
        md_no_det.var_outer(df_test, df_det="nom")

        ## Test assertions
        with self.assertRaises(ValueError):
            self.model_3d.var_outer(self.df_2d, df_det=self.df_2d)
Example #13
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    def test_function_model(self):
        md_base = gr.Model() >> gr.cp_function(
            fun=lambda x: x, var=1, out=1, name="name", runtime=1)

        ## Base constructor
        func = gr.FunctionModel(md_base)

        self.assertTrue(md_base.var == func.var)
        self.assertTrue(md_base.out == func.out)
        self.assertTrue(md_base.name == func.name)
        self.assertTrue(md_base.runtime(1) == func.runtime)

        ## Test copy
        func_copy = func.copy()

        self.assertTrue(func_copy.var == func.var)
        self.assertTrue(func_copy.out == func.out)
        self.assertTrue(func_copy.name == func.name)
        self.assertTrue(func_copy.runtime == func.runtime)
Example #14
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    def setUp(self):
        ## Linear limit state w/ MPP off initial guess
        self.beta_true = 3
        self.md = (
            gr.Model()
            >> gr.cp_function(
                fun=lambda x: self.beta_true * 2 - x[0] - np.sqrt(3) * x[1],
                var=2,
                out=["g"],
            )
            >> gr.cp_marginals(
                x0=dict(dist="norm", loc=0, scale=1, sign=1),
                x1=dict(dist="norm", loc=0, scale=1, sign=1),
            )
            >> gr.cp_copula_independence()
        )

        ## Linear limit state w/ lognormal marginals
        self.md_log = (
            gr.Model()
            >> gr.cp_vec_function(
                fun=lambda df: gr.df_make(
                    g=gr.exp(gr.sqrt(2) * 1) - df.x * df.y
                ),
                var=["x", "y"],
                out=["g"]
            )
            >> gr.cp_marginals(
                x=dict(dist="lognorm", loc=0, scale=1, s=1),
                y=dict(dist="lognorm", loc=0, scale=1, s=1),
            )
            >> gr.cp_copula_independence()
        )
        self.df_mpp = gr.df_make(
            x=gr.exp(gr.sqrt(2)/2),
            y=gr.exp(gr.sqrt(2)/2),
            beta_g=1.0,
            g=0.0,
        )

        ## Cantilever beam for flatten test
        self.md_beam = models.make_cantilever_beam()
Example #15
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    def test_comp_model(self):
        """Test model composition"""
        md_inner = (
            gr.Model("inner")
            >> gr.cp_function(fun=lambda x: x[0] + x[1], var=2, out=1)
            >> gr.cp_marginals(x0=dict(dist="norm", loc=0, scale=1))
            >> gr.cp_copula_independence()
        )

        ## Deterministic composition
        md_det = gr.Model("outer_det") >> gr.cp_md_det(md=md_inner)

        self.assertTrue(set(md_det.var) == {"x0", "x1"})
        self.assertTrue(md_det.out == ["y0"])
        gr.eval_df(md_det, df=gr.df_make(x0=0, x1=0))

        ## Deterministic composition
        md_sample = gr.Model("outer_det") >> gr.cp_md_sample(
            md=md_inner, param=dict(x0=("loc", "scale"))
        )

        self.assertTrue(set(md_sample.var) == {"x0_loc", "x0_scale", "x1"})
        self.assertTrue(set(md_sample.out) == {"y0"})
        gr.eval_df(md_sample, df=gr.df_make(x0_loc=0, x0_scale=1, x1=0))
Example #16
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    def test_nls(self):
        ## Ground-truth model
        c_true = 2
        a_true = 1

        md_true = (gr.Model() >> gr.cp_function(
            fun=lambda x: a_true * np.exp(x[0] * c_true) + x[1],
            var=["x", "epsilon"],
            out=["y"],
        ) >> gr.cp_marginals(epsilon={
            "dist": "norm",
            "loc": 0,
            "scale": 0.5
        }) >> gr.cp_copula_independence())
        df_data = md_true >> gr.ev_monte_carlo(
            n=5, seed=101, df_det=gr.df_make(x=[0, 1, 2, 3, 4]))

        ## Model to fit
        md_param = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[2] * np.exp(x[0] * x[1]),
            var=["x", "c", "a"],
            out=["y"]) >> gr.cp_bounds(c=[0, 4], a=[0.1, 2.0]))

        ## Fit the model
        md_fit = df_data >> gr.ft_nls(
            md=md_param,
            verbose=False,
            uq_method="linpool",
        )

        ## Unidentifiable model throws warning
        # -------------------------
        md_unidet = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[2] / x[3] * np.exp(x[0] * x[1]),
            var=["x", "c", "a", "z"],
            out=["y"],
        ) >> gr.cp_bounds(c=[0, 4], a=[0.1, 2.0], z=[0, 1]))
        with self.assertWarns(RuntimeWarning):
            gr.fit_nls(
                df_data,
                md=md_unidet,
                uq_method="linpool",
            )

        ## True parameters in wide confidence region
        # -------------------------
        alpha = 1e-3
        self.assertTrue(
            (md_fit.density.marginals["c"].q(alpha / 2) <= c_true)
            and (c_true <= md_fit.density.marginals["c"].q(1 - alpha / 2)))

        self.assertTrue(
            (md_fit.density.marginals["a"].q(alpha / 2) <= a_true)
            and (a_true <= md_fit.density.marginals["a"].q(1 - alpha / 2)))

        ## Model with fixed parameter
        # -------------------------
        md_fixed = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[2] * np.exp(x[0] * x[1]),
            var=["x", "c", "a"],
            out=["y"]) >> gr.cp_bounds(c=[0, 4], a=[1, 1]))
        md_fit_fixed = df_data >> gr.ft_nls(
            md=md_fixed, verbose=False, uq_method="linpool")

        # Test that fixed model can evaluate successfully
        gr.eval_monte_carlo(md_fit_fixed, n=1, df_det="nom")

        ## Trajectory model
        # -------------------------
        md_base = models.make_trajectory_linear()
        md_fit = data.df_trajectory_windowed >> gr.ft_nls(
            md=md_base, method="SLSQP", tol=1e-3)
        df_tmp = md_fit >> gr.ev_nominal(df_det="nom")
Example #17
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    def test_comp_function(self):
        """Test comp_function()"""

        md_new0 = gr.comp_function(self.md, fun=lambda x: x, var=1, out=1)
        md_new1 = gr.comp_function(md_new0, fun=lambda x: x, var=1, out=1)

        ## Operations above should not affect self.md
        md_named = gr.comp_function(
            self.md,
            fun=lambda x: [x, 2 * x],
            var=["foo"],
            out=["bar1", "bar2"],
            name="test",
        )

        ## Default var and out names
        self.assertEqual(md_new0.var, ["x0"])
        self.assertEqual(md_new0.out, ["y0"])

        ## New default names iterate counter
        self.assertEqual(set(md_new1.var), set(["x0", "x1"]))
        self.assertEqual(set(md_new1.out), set(["y0", "y1"]))

        ## Output names assigned correctly
        # Also tests for copy issues
        self.assertEqual(set(md_named.out), set(["bar1", "bar2"]))
        ## Function name assigned correctly
        self.assertEqual(md_named.functions[0].name, "test")

        ## Invariant checks
        with self.assertRaises(ValueError):
            # Missing function
            gr.comp_function(self.md, fun=None, var=["foo"], out=["bar"])
        with self.assertRaises(ValueError):
            # Missing var
            gr.comp_function(self.md, fun=lambda x: x, var=None, out=["bar"])
        with self.assertRaises(ValueError):
            # Missing out
            gr.comp_function(self.md, fun=lambda x: x, var=["foo"], out=None)
        with self.assertRaises(ValueError):
            # Intersection var / out names
            self.md >> gr.cp_function(lambda x: x, var=["x"], out=["x"], name="f0")
        with self.assertRaises(ValueError):
            # Non-unique function names
            self.md >> gr.cp_function(
                lambda x: x, var=1, out=1, name="f0"
            ) >> gr.cp_function(lambda x: x, var=1, out=1, name="f0")
        ## DAG invariant checks
        with self.assertRaises(ValueError):
            # Cycle by input
            self.md >> gr.cp_function(
                fun=lambda x: x[0], var=["y0"], out=1
            ) >> gr.cp_function(fun=lambda x: x[0], var=1, out=["y0"])
        with self.assertRaises(ValueError):
            # Non-unique output
            self.md >> gr.cp_function(
                fun=lambda x: x[0], var=1, out=["y0"]
            ) >> gr.cp_function(fun=lambda x: x[0], var=1, out=["y0"])

        ## Check vectorized builder
        md_vec = gr.comp_vec_function(
            self.md, fun=lambda df: df.assign(y0=df.x0), var=1, out=1,
        )
        self.assertTrue(
            gr.df_equal(gr.df_make(x0=0, y0=0), md_vec >> gr.ev_df(df=gr.df_make(x0=0)))
        )
Example #18
0
    def test_nls(self):
        ## Setup
        md_feat = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[0] * x[1] + x[2],
            var=3,
            out=1,
        ) >> gr.cp_bounds(x0=[-1, +1], x2=[0, 0]) >>
                   gr.cp_marginals(x1=dict(dist="norm", loc=0, scale=1)))

        md_const = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[0], var=1, out=1) >> gr.cp_bounds(x0=(-1, +1)))

        df_response = md_feat >> gr.ev_df(
            df=gr.df_make(x0=0.1, x1=[-1, -0.5, +0, +0.5, +1], x2=0))
        df_data = df_response[["x1", "y0"]]

        ## Model with features
        df_true = gr.df_make(x0=0.1)
        df_fit = md_feat >> gr.ev_nls(df_data=df_data, append=False)

        pd.testing.assert_frame_equal(
            df_fit,
            df_true,
            check_exact=False,
            check_dtype=False,
            check_column_type=False,
        )
        ## Fitting synonym
        md_feat_fit = df_data >> gr.ft_nls(md=md_feat, verbose=False)
        self.assertTrue(set(md_feat_fit.var) == set(["x1", "x2"]))

        ## Constant model
        df_const = gr.df_make(x0=0)
        df_fit = md_const >> gr.ev_nls(df_data=gr.df_make(y0=[-1, 0, +1]))

        pd.testing.assert_frame_equal(
            df_fit,
            df_const,
            check_exact=False,
            check_dtype=False,
            check_column_type=False,
        )

        ## Multiple restarts works
        df_multi = gr.eval_nls(md_feat, df_data=df_data, n_restart=2)
        self.assertTrue(df_multi.shape[0] == 2)

        ## Specified initial guess
        df_spec = gr.eval_nls(md_feat,
                              df_data=df_data,
                              df_init=gr.df_make(x0=0.5),
                              append=False)
        pd.testing.assert_frame_equal(
            df_spec,
            df_true,
            check_exact=False,
            check_dtype=False,
            check_column_type=False,
        )
        # Raises if incorrect guess data
        with self.assertRaises(ValueError):
            gr.eval_nls(md_feat, df_data=df_data, df_init=gr.df_make(foo=0.5))
Example #19
0
    def test_nls(self):
        ## Ground-truth model
        c_true = 2
        a_true = 1

        md_true = (gr.Model() >> gr.cp_function(
            fun=lambda x: a_true * np.exp(x[0] * c_true) + x[1],
            var=["x", "epsilon"],
            out=["y"],
        ) >> gr.cp_marginals(epsilon={
            "dist": "norm",
            "loc": 0,
            "scale": 0.5
        }) >> gr.cp_copula_independence())
        df_data = md_true >> gr.ev_sample(
            n=5, seed=101, df_det=gr.df_make(x=[0, 1, 2, 3, 4]))

        ## Model to fit
        md_param = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[2] * np.exp(x[0] * x[1]),
            var=["x", "c", "a"],
            out=["y"]) >> gr.cp_bounds(c=[0, 4], a=[0.1, 2.0]))

        ## Fit the model
        md_fit = df_data >> gr.ft_nls(
            md=md_param,
            verbose=False,
            uq_method="linpool",
        )

        ## Unidentifiable model throws warning
        # -------------------------
        md_unidet = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[2] / x[3] * np.exp(x[0] * x[1]),
            var=["x", "c", "a", "z"],
            out=["y"],
        ) >> gr.cp_bounds(c=[0, 4], a=[0.1, 2.0], z=[0, 1]))
        with self.assertWarns(RuntimeWarning):
            gr.fit_nls(
                df_data,
                md=md_unidet,
                uq_method="linpool",
            )

        ## True parameters in wide confidence region
        # -------------------------
        alpha = 1e-3
        self.assertTrue(
            (md_fit.density.marginals["c"].q(alpha / 2) <= c_true)
            and (c_true <= md_fit.density.marginals["c"].q(1 - alpha / 2)))

        self.assertTrue(
            (md_fit.density.marginals["a"].q(alpha / 2) <= a_true)
            and (a_true <= md_fit.density.marginals["a"].q(1 - alpha / 2)))

        ## Model with fixed parameter
        # -------------------------
        md_fixed = (gr.Model() >> gr.cp_function(
            fun=lambda x: x[2] * np.exp(x[0] * x[1]),
            var=["x", "c", "a"],
            out=["y"]) >> gr.cp_bounds(c=[0, 4], a=[1, 1]))
        md_fit_fixed = df_data >> gr.ft_nls(
            md=md_fixed, verbose=False, uq_method="linpool")

        # Test that fixed model can evaluate successfully
        gr.eval_sample(md_fit_fixed, n=1, df_det="nom")

        ## Trajectory model
        # -------------------------
        md_base = models.make_trajectory_linear()
        md_fit = data.df_trajectory_windowed >> gr.ft_nls(
            md=md_base, method="SLSQP", tol=1e-3)
        df_tmp = md_fit >> gr.ev_nominal(df_det="nom")

        ## Select output for fitting
        # -------------------------
        # Split model has inconsistent "true" parameter value
        md_split = (gr.Model("Split") >> gr.cp_vec_function(
            fun=lambda df: gr.df_make(
                f=1 * df.c * df.x,
                g=2 * df.c * df.x,
            ),
            var=["c", "x"],
            out=["f", "g"],
        ) >> gr.cp_bounds(
            x=(-1, +1),
            c=(-1, +1),
        ))

        df_split = (gr.df_make(x=gr.linspace(-1, +1, 100)) >> gr.tf_mutate(
            f=X.x, g=X.x))

        # Fitting both outputs: cannot achieve mse ~= 0
        df_both = (df_split >> gr.ft_nls(md_split, out=["f", "g"]) >>
                   gr.ev_df(df_split >> gr.tf_rename(f_t=X.f, g_t=X.g)) >>
                   gr.tf_summarize(
                       mse_f=gr.mse(X.f, X.f_t),
                       mse_g=gr.mse(X.g, X.g_t),
                   ))
        self.assertTrue(df_both.mse_f[0] > 0)
        self.assertTrue(df_both.mse_g[0] > 0)

        # Fitting "f" only
        df_f = (df_split >> gr.ft_nls(md_split, out=["f"]) >>
                gr.ev_df(df_split >> gr.tf_rename(f_t=X.f, g_t=X.g)) >>
                gr.tf_summarize(
                    mse_f=gr.mse(X.f, X.f_t),
                    mse_g=gr.mse(X.g, X.g_t),
                ))
        self.assertTrue(df_f.mse_f[0] < 1e-16)
        self.assertTrue(df_f.mse_g[0] > 0)

        # Fitting "g" only
        df_g = (df_split >> gr.ft_nls(md_split, out=["g"]) >>
                gr.ev_df(df_split >> gr.tf_rename(f_t=X.f, g_t=X.g)) >>
                gr.tf_summarize(
                    mse_f=gr.mse(X.f, X.f_t),
                    mse_g=gr.mse(X.g, X.g_t),
                ))
        self.assertTrue(df_g.mse_f[0] > 0)
        self.assertTrue(df_g.mse_g[0] < 1e-16)