diff --git a/examples/wave/wave-eager.py b/examples/wave/wave-eager.py
new file mode 100644
index 0000000000000000000000000000000000000000..aa9e87ffa0a7885adf9cc8d67d82d1be15a44e93
--- /dev/null
+++ b/examples/wave/wave-eager.py
@@ -0,0 +1,185 @@
+from __future__ import division, print_function
+
+__copyright__ = "Copyright (C) 2020 Andreas Kloeckner"
+
+__license__ = """
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+
+
+import numpy as np
+import numpy.linalg as la # noqa
+import pyopencl as cl
+import pyopencl.array as cla # noqa
+import pyopencl.clmath as clmath
+from pytools.obj_array import (
+ join_fields, make_obj_array,
+ with_object_array_or_scalar)
+from meshmode.mesh import BTAG_ALL, BTAG_NONE # noqa
+from grudge.eager import EagerDGDiscretization, with_queue
+from grudge.symbolic.primitives import TracePair
+from grudge.shortcuts import make_visualizer
+
+
+def interior_trace_pair(discr, vec):
+ i = discr.interp("vol", "int_faces", vec)
+ e = with_object_array_or_scalar(
+ lambda el: discr.opposite_face_connection()(el.queue, el),
+ i)
+ return TracePair("int_faces", i, e)
+
+
+# {{{ wave equation bits
+
+def wave_flux(discr, c, w_tpair):
+ u = w_tpair[0]
+ v = w_tpair[1:]
+
+ normal = with_queue(u.int.queue, discr.normal(w_tpair.dd))
+
+ def normal_times(scalar):
+ # workaround for object array behavior
+ return make_obj_array([ni*scalar for ni in normal])
+
+ flux_weak = join_fields(
+ np.dot(v.avg, normal),
+ normal_times(u.avg),
+ )
+
+ # upwind
+ v_jump = np.dot(normal, v.int-v.ext)
+ flux_weak -= join_fields(
+ 0.5*(u.int-u.ext),
+ 0.5*normal_times(v_jump),
+ )
+
+ return discr.interp(w_tpair.dd, "all_faces", c*flux_weak)
+
+
+def wave_operator(discr, c, w):
+ u = w[0]
+ v = w[1:]
+
+ dir_u = discr.interp("vol", BTAG_ALL, u)
+ dir_v = discr.interp("vol", BTAG_ALL, v)
+ dir_bval = join_fields(dir_u, dir_v)
+ dir_bc = join_fields(-dir_u, dir_v)
+
+ return (
+ discr.inverse_mass(
+ join_fields(
+ c*discr.weak_div(v),
+ c*discr.weak_grad(u)
+ )
+ - # noqa: W504
+ discr.face_mass(
+ wave_flux(discr, c=c, w_tpair=interior_trace_pair(discr, w))
+ + wave_flux(discr, c=c, w_tpair=TracePair(
+ BTAG_ALL, dir_bval, dir_bc))
+ ))
+ )
+
+# }}}
+
+
+def rk4_step(y, t, h, f):
+ k1 = f(t, y)
+ k2 = f(t+h/2, y + h/2*k1)
+ k3 = f(t+h/2, y + h/2*k2)
+ k4 = f(t+h, y + h*k3)
+ return y + h/6*(k1 + 2*k2 + 2*k3 + k4)
+
+
+def bump(discr, queue, t=0):
+ source_center = np.array([0.2, 0.35, 0.1])[:discr.dim]
+ source_width = 0.05
+ source_omega = 3
+
+ nodes = discr.nodes().with_queue(queue)
+ center_dist = join_fields([
+ nodes[i] - source_center[i]
+ for i in range(discr.dim)
+ ])
+
+ return (
+ np.cos(source_omega*t)
+ * clmath.exp(
+ -np.dot(center_dist, center_dist)
+ / source_width**2))
+
+
+def main():
+ cl_ctx = cl.create_some_context()
+ queue = cl.CommandQueue(cl_ctx)
+
+ dim = 2
+ nel_1d = 16
+ from meshmode.mesh.generation import generate_regular_rect_mesh
+ mesh = generate_regular_rect_mesh(
+ a=(-0.5,)*dim,
+ b=(0.5,)*dim,
+ n=(nel_1d,)*dim)
+
+ order = 3
+
+ if dim == 2:
+ # no deep meaning here, just a fudge factor
+ dt = 0.75/(nel_1d*order**2)
+ elif dim == 3:
+ # no deep meaning here, just a fudge factor
+ dt = 0.45/(nel_1d*order**2)
+ else:
+ raise ValueError("don't have a stable time step guesstimate")
+
+ print("%d elements" % mesh.nelements)
+
+ discr = EagerDGDiscretization(cl_ctx, mesh, order=order)
+
+ fields = join_fields(
+ bump(discr, queue),
+ [discr.zeros(queue) for i in range(discr.dim)]
+ )
+
+ vis = make_visualizer(discr, discr.order+3 if dim == 2 else discr.order)
+
+ def rhs(t, w):
+ return wave_operator(discr, c=1, w=w)
+
+ t = 0
+ t_final = 3
+ istep = 0
+ while t < t_final:
+ fields = rk4_step(fields, t, dt, rhs)
+
+ if istep % 10 == 0:
+ print(istep, t, la.norm(fields[0].get()))
+ vis.write_vtk_file("fld-wave-eager-%04d.vtu" % istep,
+ [
+ ("u", fields[0]),
+ ("v", fields[1:]),
+ ])
+
+ t += dt
+ istep += 1
+
+
+if __name__ == "__main__":
+ main()
+
+# vim: foldmethod=marker
diff --git a/grudge/eager.py b/grudge/eager.py
new file mode 100644
index 0000000000000000000000000000000000000000..e64e2fa8344a848f4d0a218cfd0286ec9f896e2a
--- /dev/null
+++ b/grudge/eager.py
@@ -0,0 +1,111 @@
+from __future__ import division, print_function
+
+__copyright__ = "Copyright (C) 2020 Andreas Kloeckner"
+
+__license__ = """
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+"""
+
+
+import numpy as np # noqa
+from grudge.discretization import DGDiscretizationWithBoundaries
+from pytools import memoize_method
+from pytools.obj_array import (
+ with_object_array_or_scalar,
+ is_obj_array)
+import pyopencl as cl
+import pyopencl.array as cla # noqa
+from grudge import sym, bind
+from meshmode.mesh import BTAG_ALL, BTAG_NONE # noqa
+
+
+def with_queue(queue, ary):
+ return with_object_array_or_scalar(
+ lambda x: x.with_queue(queue), ary)
+
+
+def without_queue(ary):
+ return with_queue(None, ary)
+
+
+class EagerDGDiscretization(DGDiscretizationWithBoundaries):
+ def interp(self, src, tgt, vec):
+ if is_obj_array(vec):
+ return with_object_array_or_scalar(
+ lambda el: self.interp(src, tgt, el), vec)
+
+ return self.connection_from_dds(src, tgt)(vec.queue, vec)
+
+ def nodes(self):
+ return self._volume_discr.nodes()
+
+ @memoize_method
+ def _bound_grad(self):
+ return bind(self, sym.nabla(self.dim) * sym.Variable("u"))
+
+ def grad(self, vec):
+ return self._bound_grad()(vec.queue, u=vec)
+
+ def div(self, vecs):
+ return sum(
+ self.grad(vec_i)[i] for i, vec_i in enumerate(vecs))
+
+ @memoize_method
+ def _bound_weak_grad(self):
+ return bind(self, sym.stiffness_t(self.dim) * sym.Variable("u"))
+
+ def weak_grad(self, vec):
+ return self._bound_weak_grad()(vec.queue, u=vec)
+
+ def weak_div(self, vecs):
+ return sum(
+ self.weak_grad(vec_i)[i] for i, vec_i in enumerate(vecs))
+
+ @memoize_method
+ def normal(self, dd):
+ with cl.CommandQueue(self.cl_context) as queue:
+ surface_discr = self.discr_from_dd(dd)
+ return without_queue(
+ bind(self, sym.normal(
+ dd, surface_discr.ambient_dim, surface_discr.dim))(queue))
+
+ @memoize_method
+ def _bound_inverse_mass(self):
+ return bind(self, sym.InverseMassOperator()(sym.Variable("u")))
+
+ def inverse_mass(self, vec):
+ if is_obj_array(vec):
+ return with_object_array_or_scalar(
+ lambda el: self.inverse_mass(el), vec)
+
+ return self._bound_inverse_mass()(vec.queue, u=vec)
+
+ @memoize_method
+ def _bound_face_mass(self):
+ u = sym.Variable("u", dd=sym.as_dofdesc("all_faces"))
+ return bind(self, sym.FaceMassOperator()(u))
+
+ def face_mass(self, vec):
+ if is_obj_array(vec):
+ return with_object_array_or_scalar(
+ lambda el: self.face_mass(el), vec)
+
+ return self._bound_face_mass()(vec.queue, u=vec)
+
+# vim: foldmethod=marker