Triggered assertion 'no weights' on a valid functional

[Martin Sandve Alnæs]

from dolfin import *
mesh = UnitSquare(10,10)
assemble(1.0/(y+1)*dx, mesh=mesh) # works
assemble((y+1)**-1*dx, mesh=mesh) # triggers assertion

Traceback:

---------------------------------------------------------------------------
Exception Traceback (most recent call last)

/home/martinal/dev/fenics/ffc/work/test/<ipython console> in <module>()

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/dolfin/fem/assembling.pyc in assemble(form, tensor, mesh, coefficients, function_spaces, cell_domains, exterior_facet_domains, interior_facet_domains, reset_sparsity, add_values, finalize_tensor, backend, form_compiler_parameters)
    156 coefficients=coefficients,
    157 form_compiler_parameters=form_compiler_parameters,
--> 158 common_cell=common_cell)
    159
    160 # Set mesh if specified (important for functionals without a function spaces)

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/dolfin/fem/form.pyc in __init__(self, form, function_spaces, coefficients, subdomains, form_compiler_parameters, common_cell)
     52 = jit(form,
     53 form_compiler_parameters,
---> 54 common_cell)
     55 else:
     56 self._compiled_form = form

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/dolfin/compilemodules/jit.pyc in mpi_jit(*args, **kwargs)
     64 # Just call JIT compiler when running in serial

     65 if MPI.num_processes() == 1:
---> 66 return local_jit(*args, **kwargs)
     67
     68 # Compile first on process 0

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/dolfin/compilemodules/jit.pyc in jit(form, form_compiler_parameters, common_cell)
    148 jit_compile = form_compiler.jit
    149 except AttributeError:
    150 raise RuntimeError, "Form compiler must implement the jit function."
    151
--> 152 return jit_compile(form, parameters=p, common_cell=common_cell)

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/jitcompiler.pyc in jit(ufl_object, parameters, common_cell)
     71 return jit_element(ufl_object, parameters)
     72 else:
---> 73 return jit_form(ufl_object, parameters, common_cell)
     74
     75 def jit_form(form, parameters=None, common_cell=None):

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/jitcompiler.pyc in jit_form(form, parameters, common_cell)
    128 prefix=prefix,
    129 parameters=parameters,
--> 130 common_cell=common_cell)
    131
    132 # Build module using Instant (through UFC)

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/compiler.pyc in compile_form(forms, object_names, prefix, parameters, common_cell)
    163 # Stage 4: code generation

    164 cpu_time = time()
--> 165 code = generate_code(oir, prefix, parameters)
    166 _print_timing(4, time() - cpu_time)
    167

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/codegeneration.pyc in generate_code(ir, prefix, parameters)
     74 # Generate code for integrals

     75 info("Generating code for integrals")
---> 76 code_integrals = [_generate_integral_code(ir, prefix, parameters) for ir in ir_integrals]
     77
     78 # Generate code for forms

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/codegeneration.pyc in _generate_integral_code(ir, prefix, parameters)
    198
    199 # Generate code

--> 200 code = r.generate_integral_code(ir, prefix, parameters)
    201
    202 # Indent code (unused variables should already be removed)

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature/quadraturegenerator.pyc in generate_integral_code(ir, prefix, parameters)
     51 code["initializer_list"] = ""
     52 code["destructor"] = format["do nothing"]
---> 53 code["tabulate_tensor"] = _tabulate_tensor(ir, parameters)
     54 code["tabulate_tensor_quadrature"] = format["exception"](tabulate_tensor_quadrature_error)
     55 code["additional_includes_set"] = ir["additional_includes_set"]

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature/quadraturegenerator.pyc in _tabulate_tensor(ir, parameters)
    165 # the unused transformations and tabulate the used psi tables and weights.

    166 common = [remove_unused(jacobi_code, trans_set)]
--> 167 common += _tabulate_weights([quadrature_weights[p] for p in used_weights])
    168 name_map = ir["name_map"]
    169 tables = ir["unique_tables"]

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature/quadraturegenerator.pyc in _tabulate_weights(quadrature_weights)
    453 # FIXME: For now, raise error if we don't have weights.

    454 # We might want to change this later.

--> 455 ffc_assert(weights.any(), "No weights.")
    456
    457 # Create name and value for weight.

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/log.pyc in ffc_assert(condition, *message)
     44 def ffc_assert(condition, *message):
     45 "Assert that condition is true and otherwise issue an error with given message."
---> 46 condition or error(*message)
     47
     48 # Set default log level

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/log.pyc in <lambda>(*message)

/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ufl/log.pyc in error(self, *message)
    146 "Write error message and raise an exception."
    147 self._log.error(*message)
--> 148 raise self._exception_type(self._format_raw(*message))
    149
    150 def begin(self, *message):

Exception: No weights.

[Marie Rognes (meg-simula)]

What is y? (I rather get NameError: name 'y' is not defined ;-) )

[Martin Sandve Alnæs (martinal)]

Going through my reported bugs I found this, and it is still there with a slightly different message. Heres a working reproduction:

from dolfin import *
mesh = UnitSquareMesh(10,10)
x, y = mesh.ufl_cell().x
print assemble(1.0/(y+1)*dx, mesh=mesh) # works
print assemble((y+1)**-1*dx, mesh=mesh) # triggers assertion

now gives

...
  File "/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature/quadraturerepresentation.py", line 193, in _tabulate_basis
    (points, weights) = create_quadrature(cell_domain, degree, rule)
  File "/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature_schemes.py", line 70, in create_quadrature
    return _triangle_scheme(degree)
  File "/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature_schemes.py", line 160, in _triangle_scheme
    x, w = _fiat_scheme("triangle", degree)
  File "/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/quadrature_schemes.py", line 85, in _fiat_scheme
    return fiat_create_quadrature(shape, num_points_per_axis)
  File "/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/ffc/fiatinterface.py", line 145, in create_quadrature
    quad_rule = FIAT.make_quadrature(reference_cell(shape), num_points)
  File "/home/martinal/opt/fenics/dorsal-unstable/lib/python2.7/site-packages/FIAT/quadrature.py", line 169, in make_quadrature
    assert (m > 0), msg
AssertionError: Expecting at least one (not 0) quadrature point per direction

[Kristian B. Ølgaard (k.b.oelgaard)]

The error is in 'estimate_total_polynomial_degree' from algorithms which returns 1 for the first form and -1 for the second