From f30cb6df8c559db0d6cb7338742089c8cf327e27 Mon Sep 17 00:00:00 2001
From: Gene Lin <genelin@GenedeMacBook-Air.local>
Date: Sun, 21 Jul 2024 11:31:57 +0800
Subject: [PATCH 1/6] hide boundary points in figure

---
 modmesh/app/euler1d.py    | 20 +++++++++++---------
 modmesh/onedim/euler1d.py |  3 ++-
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/modmesh/app/euler1d.py b/modmesh/app/euler1d.py
index f1f79598..53495f6b 100644
--- a/modmesh/app/euler1d.py
+++ b/modmesh/app/euler1d.py
@@ -511,6 +511,8 @@ def set_solver_config(self):
         self.interval = self.solver_config.get_var("timer_interval", "value")
         self.max_steps = self.solver_config.get_var("max_steps", "value")
         self.profiling = self.solver_config.get_var("profiling", "value")
+        ncoord = self.solver_config.get_var("ncoord", "value")
+        self.plot_point = np.linspace(2, (ncoord - 3), num=((ncoord - 3) // 2), dtype=int)
 
     def setup_timer(self):
         """
@@ -530,7 +532,7 @@ def build_grid_figure(self):
 
         :return: FigureCanvas
         """
-        x = self.st.svr.coord[::2]
+        x = self.st.svr.coord[self.plot_point]
         fig = Figure()
         canvas = FigureCanvas(fig)
         ax = canvas.figure.subplots(3, 2)
@@ -574,7 +576,7 @@ def build_single_figure(self):
 
         :return: FigureCanvas
         """
-        x = self.st.svr.coord[::2]
+        x = self.st.svr.coord[self.plot_point]
         fig = Figure()
         canvas = FigureCanvas(fig)
         ax = canvas.figure.subplots()
@@ -744,23 +746,23 @@ def update_lines(self):
         """
         if self.use_grid_layout:
             self.density.update(adata=self.st.density_field,
-                                ndata=self.st.svr.density[::2])
+                                ndata=self.st.svr.density[self.plot_point])
             self.pressure.update(adata=self.st.pressure_field,
-                                 ndata=self.st.svr.pressure[::2])
+                                 ndata=self.st.svr.pressure[self.plot_point])
             self.velocity.update(adata=self.st.velocity_field,
-                                 ndata=self.st.svr.velocity[::2])
+                                 ndata=self.st.svr.velocity[self.plot_point])
             self.temperature.update(adata=self.st.temperature_field,
-                                    ndata=self.st.svr.temperature[::2])
+                                    ndata=self.st.svr.temperature[self.plot_point])
             self.internal_energy.update(adata=(self.st.internal_energy_field),
                                         ndata=(self.st.svr.
-                                               internal_energy[::2]))
+                                               internal_energy[self.plot_point]))
             self.entropy.update(adata=self.st.entropy_field,
-                                ndata=self.st.svr.entropy[::2])
+                                ndata=self.st.svr.entropy[self.plot_point])
         else:
             for name, is_selected, *_ in self.plot_config.state:
                 if is_selected:
                     eval(f'(self.{name}.update(adata=self.st.{name}_field,'
-                         f' ndata=self.st.svr.{name}[::2]))')
+                         f' ndata=self.st.svr.{name}[self.plot_point]))')
 
 
 class PlotArea(PuiInQt):
diff --git a/modmesh/onedim/euler1d.py b/modmesh/onedim/euler1d.py
index 90297d8a..4dfcf266 100644
--- a/modmesh/onedim/euler1d.py
+++ b/modmesh/onedim/euler1d.py
@@ -311,7 +311,8 @@ def build_field(self, t, coord=None):
         :return: None
         """
         if None is coord:
-            coord = self.svr.coord[::2]  # Use the numerical solver.
+            plot_point = np.linspace(2, (self.svr.ncoord - 3), num=((self.svr.ncoord - 3) // 2), dtype=int)
+            coord = self.svr.coord[plot_point]  # Use the numerical solver.
         self.coord = coord.copy()  # Make a copy; no write back to argument.
 
         # Determine the zone location and the Boolean selection arrays.

From 059272a73c6039d9653b96080138d554bbcf15ea Mon Sep 17 00:00:00 2001
From: Gene Lin <genelin@GenedeMacBook-Air.local>
Date: Thu, 25 Jul 2024 17:29:28 +0800
Subject: [PATCH 2/6] set xindices as an option

---
 modmesh/app/euler1d.py    | 20 +++++++++-----------
 modmesh/onedim/euler1d.py | 10 +++++++---
 startup.py                |  3 +++
 3 files changed, 19 insertions(+), 14 deletions(-)
 create mode 100644 startup.py

diff --git a/modmesh/app/euler1d.py b/modmesh/app/euler1d.py
index 53495f6b..e5528c93 100644
--- a/modmesh/app/euler1d.py
+++ b/modmesh/app/euler1d.py
@@ -511,8 +511,6 @@ def set_solver_config(self):
         self.interval = self.solver_config.get_var("timer_interval", "value")
         self.max_steps = self.solver_config.get_var("max_steps", "value")
         self.profiling = self.solver_config.get_var("profiling", "value")
-        ncoord = self.solver_config.get_var("ncoord", "value")
-        self.plot_point = np.linspace(2, (ncoord - 3), num=((ncoord - 3) // 2), dtype=int)
 
     def setup_timer(self):
         """
@@ -532,7 +530,7 @@ def build_grid_figure(self):
 
         :return: FigureCanvas
         """
-        x = self.st.svr.coord[self.plot_point]
+        x = self.st.svr.coord[self.st.xindices]
         fig = Figure()
         canvas = FigureCanvas(fig)
         ax = canvas.figure.subplots(3, 2)
@@ -576,7 +574,7 @@ def build_single_figure(self):
 
         :return: FigureCanvas
         """
-        x = self.st.svr.coord[self.plot_point]
+        x = self.st.svr.coord[self.st.xindices]
         fig = Figure()
         canvas = FigureCanvas(fig)
         ax = canvas.figure.subplots()
@@ -746,23 +744,23 @@ def update_lines(self):
         """
         if self.use_grid_layout:
             self.density.update(adata=self.st.density_field,
-                                ndata=self.st.svr.density[self.plot_point])
+                                ndata=self.st.svr.density[self.st.xindices])
             self.pressure.update(adata=self.st.pressure_field,
-                                 ndata=self.st.svr.pressure[self.plot_point])
+                                 ndata=self.st.svr.pressure[self.st.xindices])
             self.velocity.update(adata=self.st.velocity_field,
-                                 ndata=self.st.svr.velocity[self.plot_point])
+                                 ndata=self.st.svr.velocity[self.st.xindices])
             self.temperature.update(adata=self.st.temperature_field,
-                                    ndata=self.st.svr.temperature[self.plot_point])
+                                    ndata=self.st.svr.temperature[self.st.xindices])
             self.internal_energy.update(adata=(self.st.internal_energy_field),
                                         ndata=(self.st.svr.
-                                               internal_energy[self.plot_point]))
+                                               internal_energy[self.st.xindices]))
             self.entropy.update(adata=self.st.entropy_field,
-                                ndata=self.st.svr.entropy[self.plot_point])
+                                ndata=self.st.svr.entropy[self.st.xindices])
         else:
             for name, is_selected, *_ in self.plot_config.state:
                 if is_selected:
                     eval(f'(self.{name}.update(adata=self.st.{name}_field,'
-                         f' ndata=self.st.svr.{name}[self.plot_point]))')
+                         f' ndata=self.st.svr.{name}[self.st.xindices]))')
 
 
 class PlotArea(PuiInQt):
diff --git a/modmesh/onedim/euler1d.py b/modmesh/onedim/euler1d.py
index 4dfcf266..b45b9cb9 100644
--- a/modmesh/onedim/euler1d.py
+++ b/modmesh/onedim/euler1d.py
@@ -302,7 +302,7 @@ def calc_internal_energy(self, pressure, density):
     def calc_entropy(self, pressure, density):
         return pressure / (density ** self.gamma)
 
-    def build_field(self, t, coord=None):
+    def build_field(self, t, coord=None, keep_edge=False):
         """
         Populate the field data using the analytical solution.
 
@@ -310,9 +310,13 @@ def build_field(self, t, coord=None):
         :param coord: If None, take the coordinate from the numerical solver.
         :return: None
         """
+        _ = self.svr.ncoord
+        if keep_edge:
+            self.xindices = np.linspace(0, (_ - 1), num=((_ + 1) // 2), dtype=int)
+        else:
+            self.xindices = np.linspace(2, (_ - 3), num=((_ - 3) // 2), dtype=int) 
         if None is coord:
-            plot_point = np.linspace(2, (self.svr.ncoord - 3), num=((self.svr.ncoord - 3) // 2), dtype=int)
-            coord = self.svr.coord[plot_point]  # Use the numerical solver.
+            coord = self.svr.coord[self.xindices]  # Use the numerical solver.
         self.coord = coord.copy()  # Make a copy; no write back to argument.
 
         # Determine the zone location and the Boolean selection arrays.
diff --git a/startup.py b/startup.py
new file mode 100644
index 00000000..421eed69
--- /dev/null
+++ b/startup.py
@@ -0,0 +1,3 @@
+import modmesh.view as mv
+
+mv.launch()

From bae5f8e4ebae9e4109017f1d471c22bb35c13563 Mon Sep 17 00:00:00 2001
From: Gene Lin <genelin@GenedeMacBook-Air.local>
Date: Wed, 7 Aug 2024 08:34:36 +0800
Subject: [PATCH 3/6] keep boundary points in test_field_with_numerical

---
 modmesh/app/euler1d.py     | 18 +++++++++---------
 modmesh/onedim/euler1d.py  | 13 +++++++------
 tests/test_onedim_euler.py |  2 +-
 3 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/modmesh/app/euler1d.py b/modmesh/app/euler1d.py
index e5528c93..10b0d3ae 100644
--- a/modmesh/app/euler1d.py
+++ b/modmesh/app/euler1d.py
@@ -530,7 +530,7 @@ def build_grid_figure(self):
 
         :return: FigureCanvas
         """
-        x = self.st.svr.coord[self.st.xindices]
+        x = self.st.svr.coord[self.st.svr.xindices]
         fig = Figure()
         canvas = FigureCanvas(fig)
         ax = canvas.figure.subplots(3, 2)
@@ -574,7 +574,7 @@ def build_single_figure(self):
 
         :return: FigureCanvas
         """
-        x = self.st.svr.coord[self.st.xindices]
+        x = self.st.svr.coord[self.st.svr.xindices]
         fig = Figure()
         canvas = FigureCanvas(fig)
         ax = canvas.figure.subplots()
@@ -744,23 +744,23 @@ def update_lines(self):
         """
         if self.use_grid_layout:
             self.density.update(adata=self.st.density_field,
-                                ndata=self.st.svr.density[self.st.xindices])
+                                ndata=self.st.svr.density[self.st.svr.xindices])
             self.pressure.update(adata=self.st.pressure_field,
-                                 ndata=self.st.svr.pressure[self.st.xindices])
+                                 ndata=self.st.svr.pressure[self.st.svr.xindices])
             self.velocity.update(adata=self.st.velocity_field,
-                                 ndata=self.st.svr.velocity[self.st.xindices])
+                                 ndata=self.st.svr.velocity[self.st.svr.xindices])
             self.temperature.update(adata=self.st.temperature_field,
-                                    ndata=self.st.svr.temperature[self.st.xindices])
+                                    ndata=self.st.svr.temperature[self.st.svr.xindices])
             self.internal_energy.update(adata=(self.st.internal_energy_field),
                                         ndata=(self.st.svr.
-                                               internal_energy[self.st.xindices]))
+                                               internal_energy[self.st.svr.xindices]))
             self.entropy.update(adata=self.st.entropy_field,
-                                ndata=self.st.svr.entropy[self.st.xindices])
+                                ndata=self.st.svr.entropy[self.st.svr.xindices])
         else:
             for name, is_selected, *_ in self.plot_config.state:
                 if is_selected:
                     eval(f'(self.{name}.update(adata=self.st.{name}_field,'
-                         f' ndata=self.st.svr.{name}[self.st.xindices]))')
+                         f' ndata=self.st.svr.{name}[self.st.svr.xindices]))')
 
 
 class PlotArea(PuiInQt):
diff --git a/modmesh/onedim/euler1d.py b/modmesh/onedim/euler1d.py
index b45b9cb9..8a122a30 100644
--- a/modmesh/onedim/euler1d.py
+++ b/modmesh/onedim/euler1d.py
@@ -310,13 +310,14 @@ def build_field(self, t, coord=None, keep_edge=False):
         :param coord: If None, take the coordinate from the numerical solver.
         :return: None
         """
-        _ = self.svr.ncoord
-        if keep_edge:
-            self.xindices = np.linspace(0, (_ - 1), num=((_ + 1) // 2), dtype=int)
-        else:
-            self.xindices = np.linspace(2, (_ - 3), num=((_ - 3) // 2), dtype=int) 
+
         if None is coord:
-            coord = self.svr.coord[self.xindices]  # Use the numerical solver.
+            _ = self.svr.ncoord
+            if keep_edge:
+                self.svr.xindices = np.linspace(0, (_ - 1), num=((_ + 1) // 2), dtype=int)
+            else:
+                self.svr.xindices = np.linspace(2, (_ - 3), num=((_ - 3) // 2), dtype=int)
+            coord = self.svr.coord[self.svr.xindices]  # Use the numerical solver.
         self.coord = coord.copy()  # Make a copy; no write back to argument.
 
         # Determine the zone location and the Boolean selection arrays.
diff --git a/tests/test_onedim_euler.py b/tests/test_onedim_euler.py
index 9fde2719..98bb7fed 100644
--- a/tests/test_onedim_euler.py
+++ b/tests/test_onedim_euler.py
@@ -105,7 +105,7 @@ def test_field_without_numerical(self):
     def test_field_with_numerical(self):
         self.st.build_numerical(xmin=-1, xmax=1, ncoord=21,
                                 time_increment=0.05)
-        self.st.build_field(t=0.0)
+        self.st.build_field(t=0.0, keep_edge=True)
         self.assertIsInstance(self.st.svr, euler1d.Euler1DSolver)
         self.assertEqual(len(self.st.coord), 11)
         self._check_field_value_at_t0()

From ff4fac01b0a4a3d20c4e4ead44b4edb846fcc816 Mon Sep 17 00:00:00 2001
From: Gene Lin <genelin@GenedeMacBook-Air.local>
Date: Thu, 8 Aug 2024 20:00:00 +0800
Subject: [PATCH 4/6] format document with black

---
 modmesh/app/euler1d.py    | 37 ++++++++++++++++++++++++-------------
 modmesh/onedim/euler1d.py | 11 ++++++++---
 2 files changed, 32 insertions(+), 16 deletions(-)

diff --git a/modmesh/app/euler1d.py b/modmesh/app/euler1d.py
index 10b0d3ae..3e510bb1 100644
--- a/modmesh/app/euler1d.py
+++ b/modmesh/app/euler1d.py
@@ -743,19 +743,30 @@ def update_lines(self):
         :return: None
         """
         if self.use_grid_layout:
-            self.density.update(adata=self.st.density_field,
-                                ndata=self.st.svr.density[self.st.svr.xindices])
-            self.pressure.update(adata=self.st.pressure_field,
-                                 ndata=self.st.svr.pressure[self.st.svr.xindices])
-            self.velocity.update(adata=self.st.velocity_field,
-                                 ndata=self.st.svr.velocity[self.st.svr.xindices])
-            self.temperature.update(adata=self.st.temperature_field,
-                                    ndata=self.st.svr.temperature[self.st.svr.xindices])
-            self.internal_energy.update(adata=(self.st.internal_energy_field),
-                                        ndata=(self.st.svr.
-                                               internal_energy[self.st.svr.xindices]))
-            self.entropy.update(adata=self.st.entropy_field,
-                                ndata=self.st.svr.entropy[self.st.svr.xindices])
+            self.density.update(
+                adata=self.st.density_field,
+                ndata=self.st.svr.density[self.st.svr.xindices]
+            )
+            self.pressure.update(
+                adata=self.st.pressure_field,
+                ndata=self.st.svr.pressure[self.st.svr.xindices]
+            )
+            self.velocity.update(
+                adata=self.st.velocity_field,
+                ndata=self.st.svr.velocity[self.st.svr.xindices]
+            )
+            self.temperature.update(
+                adata=self.st.temperature_field,
+                ndata=self.st.svr.temperature[self.st.svr.xindices]
+            )
+            self.internal_energy.update(
+                adata=(self.st.internal_energy_field),
+                ndata=(self.st.svr.internal_energy[self.st.svr.xindices])
+            )
+            self.entropy.update(
+                adata=self.st.entropy_field,
+                ndata=self.st.svr.entropy[self.st.svr.xindices]
+            )
         else:
             for name, is_selected, *_ in self.plot_config.state:
                 if is_selected:
diff --git a/modmesh/onedim/euler1d.py b/modmesh/onedim/euler1d.py
index 8a122a30..4e37b950 100644
--- a/modmesh/onedim/euler1d.py
+++ b/modmesh/onedim/euler1d.py
@@ -314,10 +314,15 @@ def build_field(self, t, coord=None, keep_edge=False):
         if None is coord:
             _ = self.svr.ncoord
             if keep_edge:
-                self.svr.xindices = np.linspace(0, (_ - 1), num=((_ + 1) // 2), dtype=int)
+                self.svr.xindices = np.linspace(
+                    0, (_ - 1), num=((_ + 1) // 2), dtype=int
+                )
             else:
-                self.svr.xindices = np.linspace(2, (_ - 3), num=((_ - 3) // 2), dtype=int)
-            coord = self.svr.coord[self.svr.xindices]  # Use the numerical solver.
+                self.svr.xindices = np.linspace(
+                    2, (_ - 3), num=((_ - 3) // 2), dtype=int
+                )
+            # Use the numerical solver.
+            coord = self.svr.coord[self.svr.xindices]
         self.coord = coord.copy()  # Make a copy; no write back to argument.
 
         # Determine the zone location and the Boolean selection arrays.

From e2de8d093af1ef8cd6d6ef49da296bf7a10e1aac Mon Sep 17 00:00:00 2001
From: Gene Lin <genelin@GenedeMacBook-Air.local>
Date: Wed, 25 Sep 2024 20:59:43 +0800
Subject: [PATCH 5/6] init xindices in Euler1DSolver

---
 modmesh/app/euler1d.py    | 13 +++++++------
 modmesh/onedim/euler1d.py | 27 ++++++++++++++-------------
 startup.py                |  3 ---
 3 files changed, 21 insertions(+), 22 deletions(-)
 delete mode 100644 startup.py

diff --git a/modmesh/app/euler1d.py b/modmesh/app/euler1d.py
index 3e510bb1..a798373e 100644
--- a/modmesh/app/euler1d.py
+++ b/modmesh/app/euler1d.py
@@ -743,29 +743,30 @@ def update_lines(self):
         :return: None
         """
         if self.use_grid_layout:
+            _s = self.st.svr.xindices
             self.density.update(
                 adata=self.st.density_field,
-                ndata=self.st.svr.density[self.st.svr.xindices]
+                ndata=self.st.svr.density[_s]
             )
             self.pressure.update(
                 adata=self.st.pressure_field,
-                ndata=self.st.svr.pressure[self.st.svr.xindices]
+                ndata=self.st.svr.pressure[_s]
             )
             self.velocity.update(
                 adata=self.st.velocity_field,
-                ndata=self.st.svr.velocity[self.st.svr.xindices]
+                ndata=self.st.svr.velocity[_s]
             )
             self.temperature.update(
                 adata=self.st.temperature_field,
-                ndata=self.st.svr.temperature[self.st.svr.xindices]
+                ndata=self.st.svr.temperature[_s]
             )
             self.internal_energy.update(
                 adata=(self.st.internal_energy_field),
-                ndata=(self.st.svr.internal_energy[self.st.svr.xindices])
+                ndata=(self.st.svr.internal_energy[_s])
             )
             self.entropy.update(
                 adata=self.st.entropy_field,
-                ndata=self.st.svr.entropy[self.st.svr.xindices]
+                ndata=self.st.svr.entropy[_s]
             )
         else:
             for name, is_selected, *_ in self.plot_config.state:
diff --git a/modmesh/onedim/euler1d.py b/modmesh/onedim/euler1d.py
index 4e37b950..e23617a5 100644
--- a/modmesh/onedim/euler1d.py
+++ b/modmesh/onedim/euler1d.py
@@ -24,10 +24,16 @@ class Euler1DSolver:
     method.
     """
 
-    def __init__(self, xmin, xmax, ncoord, time_increment=0.05):
+    def __init__(self, xmin, xmax, ncoord, time_increment=0.05,
+                 keep_edge=False):
         self._core = self.init_solver(xmin, xmax, ncoord, time_increment,
                                       gamma=1.4)
         # gamma is 1.4 for air.
+        _ = self.ncoord - 1
+        start = 0 if keep_edge else 2
+        stop = _ if keep_edge else (_ - 2)
+        num = (stop - start) // 2 + 1
+        self.xindices = np.linspace(start, stop, num, dtype='int32')
 
     def __getattr__(self, name):
         return getattr(self._core, name)
@@ -310,18 +316,13 @@ def build_field(self, t, coord=None, keep_edge=False):
         :param coord: If None, take the coordinate from the numerical solver.
         :return: None
         """
-
-        if None is coord:
-            _ = self.svr.ncoord
-            if keep_edge:
-                self.svr.xindices = np.linspace(
-                    0, (_ - 1), num=((_ + 1) // 2), dtype=int
-                )
-            else:
-                self.svr.xindices = np.linspace(
-                    2, (_ - 3), num=((_ - 3) // 2), dtype=int
-                )
-            # Use the numerical solver.
+        if coord is None:
+            _ = self.svr.ncoord - 1
+            start = 0 if keep_edge else 2
+            stop = _ if keep_edge else (_ - 2)
+            num = (stop - start) // 2 + 1
+            self.svr.xindices = np.linspace(start, stop, num, dtype='int32')
+            # set the x-coordinate for numerical solver.
             coord = self.svr.coord[self.svr.xindices]
         self.coord = coord.copy()  # Make a copy; no write back to argument.
 
diff --git a/startup.py b/startup.py
deleted file mode 100644
index 421eed69..00000000
--- a/startup.py
+++ /dev/null
@@ -1,3 +0,0 @@
-import modmesh.view as mv
-
-mv.launch()

From 0936eb946f6ef750d194119026e12c8a96e3ea98 Mon Sep 17 00:00:00 2001
From: Gene Lin <genelin@GenedeMacBook-Air.local>
Date: Sat, 5 Oct 2024 15:19:08 +0800
Subject: [PATCH 6/6] refactor xindices

---
 modmesh/app/euler1d.py     | 37 +++++++++++++------------------------
 modmesh/onedim/euler1d.py  | 12 ++++--------
 tests/test_onedim_euler.py |  4 ++--
 3 files changed, 19 insertions(+), 34 deletions(-)

diff --git a/modmesh/app/euler1d.py b/modmesh/app/euler1d.py
index a798373e..3cc65b26 100644
--- a/modmesh/app/euler1d.py
+++ b/modmesh/app/euler1d.py
@@ -744,30 +744,19 @@ def update_lines(self):
         """
         if self.use_grid_layout:
             _s = self.st.svr.xindices
-            self.density.update(
-                adata=self.st.density_field,
-                ndata=self.st.svr.density[_s]
-            )
-            self.pressure.update(
-                adata=self.st.pressure_field,
-                ndata=self.st.svr.pressure[_s]
-            )
-            self.velocity.update(
-                adata=self.st.velocity_field,
-                ndata=self.st.svr.velocity[_s]
-            )
-            self.temperature.update(
-                adata=self.st.temperature_field,
-                ndata=self.st.svr.temperature[_s]
-            )
-            self.internal_energy.update(
-                adata=(self.st.internal_energy_field),
-                ndata=(self.st.svr.internal_energy[_s])
-            )
-            self.entropy.update(
-                adata=self.st.entropy_field,
-                ndata=self.st.svr.entropy[_s]
-            )
+            self.density.update(adata=self.st.density_field,
+                                ndata=self.st.svr.density[_s])
+            self.pressure.update(adata=self.st.pressure_field,
+                                 ndata=self.st.svr.pressure[_s])
+            self.velocity.update(adata=self.st.velocity_field,
+                                 ndata=self.st.svr.velocity[_s])
+            self.temperature.update(adata=self.st.temperature_field,
+                                    ndata=self.st.svr.temperature[_s])
+            self.internal_energy.update(adata=(self.st.internal_energy_field),
+                                        ndata=(self.st.svr.
+                                               internal_energy[_s]))
+            self.entropy.update(adata=self.st.entropy_field,
+                                ndata=self.st.svr.entropy[_s])
         else:
             for name, is_selected, *_ in self.plot_config.state:
                 if is_selected:
diff --git a/modmesh/onedim/euler1d.py b/modmesh/onedim/euler1d.py
index e23617a5..201deaf4 100644
--- a/modmesh/onedim/euler1d.py
+++ b/modmesh/onedim/euler1d.py
@@ -122,7 +122,7 @@ def __init__(self):
         self.svr = None
 
     def build_numerical(self, xmin, xmax, ncoord, time_increment=0.05,
-                        xdiaphragm=0.0):
+                        xdiaphragm=0.0, keep_edge=False):
         """
         After :py:meth:`build_constant` is done, optionally build the
         numerical solver :py:attr:`svr`.
@@ -139,7 +139,8 @@ def build_numerical(self, xmin, xmax, ncoord, time_increment=0.05,
 
         # Initialize the numerical solver.
         self.svr = Euler1DSolver(xmin, xmax, ncoord,
-                                 time_increment=time_increment)
+                                 time_increment=time_increment,
+                                 keep_edge=keep_edge)
 
         # Fill gamma.
         self.svr.gamma.fill(self.gamma)
@@ -308,7 +309,7 @@ def calc_internal_energy(self, pressure, density):
     def calc_entropy(self, pressure, density):
         return pressure / (density ** self.gamma)
 
-    def build_field(self, t, coord=None, keep_edge=False):
+    def build_field(self, t, coord=None):
         """
         Populate the field data using the analytical solution.
 
@@ -317,11 +318,6 @@ def build_field(self, t, coord=None, keep_edge=False):
         :return: None
         """
         if coord is None:
-            _ = self.svr.ncoord - 1
-            start = 0 if keep_edge else 2
-            stop = _ if keep_edge else (_ - 2)
-            num = (stop - start) // 2 + 1
-            self.svr.xindices = np.linspace(start, stop, num, dtype='int32')
             # set the x-coordinate for numerical solver.
             coord = self.svr.coord[self.svr.xindices]
         self.coord = coord.copy()  # Make a copy; no write back to argument.
diff --git a/tests/test_onedim_euler.py b/tests/test_onedim_euler.py
index 98bb7fed..312598eb 100644
--- a/tests/test_onedim_euler.py
+++ b/tests/test_onedim_euler.py
@@ -104,8 +104,8 @@ def test_field_without_numerical(self):
 
     def test_field_with_numerical(self):
         self.st.build_numerical(xmin=-1, xmax=1, ncoord=21,
-                                time_increment=0.05)
-        self.st.build_field(t=0.0, keep_edge=True)
+                                time_increment=0.05, keep_edge=True)
+        self.st.build_field(t=0.0)
         self.assertIsInstance(self.st.svr, euler1d.Euler1DSolver)
         self.assertEqual(len(self.st.coord), 11)
         self._check_field_value_at_t0()