tests: add explicit rk tests for dde integrators

Author: chaoming0625

brainpy/integrators/dde/explicit_rk.py

@@ -1,5 +1,8 @@
 # -*- coding: utf-8 -*-
 
+from typing import Dict
+import brainpy.math as bm
+
 from brainpy.integrators.constants import F, DT
 from brainpy.integrators.dde.base import DDEIntegrator
 from brainpy.integrators.ode import common
@@ -102,11 +105,14 @@ class Ralston2(ExplicitRKIntegrator):
 
 
 class RK2(ExplicitRKIntegrator):
-  def __init__(self, f, beta=2 / 3, var_type=None, dt=None, name=None, show_code=False):
+  def __init__(self, f, beta=2 / 3, var_type=None, dt=None, name=None,
+               state_delays: Dict[str, bm.TimeDelay] = None,
+               neutral_delays: Dict[str, bm.NeutralDelay] = None):
     self.A = [(), (beta,)]
     self.B = [1 - 1 / (2 * beta), 1 / (2 * beta)]
     self.C = [0, beta]
-    super(RK2, self).__init__(f=f, var_type=var_type, dt=dt, name=name, show_code=show_code)
+    super(RK2, self).__init__(f=f, var_type=var_type, dt=dt, name=name,
+                              state_delays=state_delays, neutral_delays=neutral_delays)
 
 
 register_dde_integrator('rk2', RK2)

brainpy/integrators/dde/tests/test_explicit_rk.py

@@ -0,0 +1,155 @@
+# -*- coding: utf-8 -*-
+
+
+import unittest
+
+import brainpy as bp
+import brainpy.math as bm
+
+
+class TestExplicitRKStateDelay(unittest.TestCase):
+  def test_euler(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='euler', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_midpoint(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='midpoint', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_heun2(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='heun2', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_ralston2(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='ralston2', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_rk2(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='rk2',
+               state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_rk3(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='rk3', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_heun3(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='heun3', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_ralston3(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='ralston3', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_ssprk3(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='ssprk3', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_rk4(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='rk4', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_ralston4(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='ralston4', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+
+  def test_rk4_38rule(self):
+    xdelay = bm.TimeDelay(bm.zeros((1,)), 1., before_t0=-1., interp_method='round')
+
+    @bp.ddeint(method='rk4_38rule', state_delays={'x': xdelay})
+    def equation(x, t, ):
+      return -xdelay(t - 1)
+
+    runner = bp.integrators.IntegratorRunner(equation, monitors=['x'])
+    runner.run(20.)
+
+    bp.visualize.line_plot(runner.mon.ts, runner.mon['x'], show=True)
+