def custom_transpose_transpose_rule(cts, *args, out_types, res_tree, lin_tree,
out_tree, **params):
if 'transpose_jaxpr_thunk' in params:
assert 'call_jaxpr' in params
transpose = make_transpose_from_thunk(params['transpose_jaxpr_thunk'],
lin_tree)
else:
assert 'call' in params
transpose = params['transpose']
call_in_tree = treedef_tuple((res_tree, lin_tree))
# TODO(frostig,mattjj): `lin_arg` indicates the inputs with respect
# to which we are transposing (via `ad.is_undefined_primal`).
# Consider passing this information to the custom transpose rule?
res_arg, lin_arg = tree_unflatten(call_in_tree, args)
del lin_arg
assert all(not ad.is_undefined_primal(x) for x in tree_leaves(res_arg))
cts = [
ad_util.zeros_like_aval(ct.aval) if type(ct) is ad_util.Zero else ct
for ct in cts
]
ct_out = tree_unflatten(out_tree, cts)
ct_lin = transpose(res_arg, ct_out)
check_transpose_rule_trees(transpose, lin_tree, tree_structure(ct_lin))
ct_lin_flat, _ = tree_flatten(tree_broadcast(lin_tree,
ct_lin,
is_leaf=lambda x: x is None),
is_leaf=lambda x: x is None)
return [None] * len(tree_leaves(res_arg)) + ct_lin_flat
def _coo_matvec_transpose(ct, data, row, col, v, *, shape, transpose):
assert not ad.is_undefined_primal(row)
assert not ad.is_undefined_primal(col)
if ad.is_undefined_primal(v):
return data, row, col, coo_matvec(data,
row,
col,
ct,
shape=shape,
transpose=not transpose)
else:
v = jnp.asarray(v)
# The following line does this, but more efficiently:
# return _coo_extract(row, col, jnp.outer(ct, v)), row, col, v
return ct[row] * v[col], row, col, v
def _coo_fromdense_transpose(ct, M, *, nnz, index_dtype):
data, row, col = ct
assert len(data) == nnz
assert row.dtype == col.dtype == index_dtype
if isinstance(row, ad.Zero) or isinstance(col, ad.Zero):
raise ValueError("Cannot transpose with respect to sparse indices")
assert ad.is_undefined_primal(M)
return coo_todense(data, row, col, shape=M.aval.shape)
def _todense_transpose(ct, *bufs, tree):
assert ad.is_undefined_primal(bufs[0])
assert not any(ad.is_undefined_primal(buf) for buf in bufs[1:])
standin = object()
obj = tree_util.tree_unflatten(tree, [standin] * len(bufs))
from jax.experimental.sparse import BCOO, bcoo_extract
if obj is standin:
return (ct,)
elif isinstance(obj, BCOO):
_, indices = bufs
return bcoo_extract(indices, ct), indices
elif isinstance(obj, COO):
_, row, col = bufs
return _coo_extract(row, col, ct), row, col
else:
raise NotImplementedError(f"todense_transpose for {type(obj)}")
def _csr_fromdense_transpose(ct, M, *, nse, index_dtype):
data, indices, indptr = ct
assert len(data) == nse
assert indices.dtype == indptr.dtype == index_dtype
if isinstance(indices, ad.Zero) or isinstance(indptr, ad.Zero):
raise ValueError("Cannot transpose with respect to sparse indices")
assert ad.is_undefined_primal(M)
return csr_todense(data, indices, indptr, shape=M.aval.shape)
def _csr_matvec_transpose(ct, data, indices, indptr, v, *, shape, transpose):
assert not ad.is_undefined_primal(indices)
assert not ad.is_undefined_primal(indptr)
if ad.is_undefined_primal(v):
return data, indices, indptr, csr_matvec(data,
indices,
indptr,
ct,
shape=shape,
transpose=not transpose)
else:
v = jnp.asarray(v)
# The following lines do this, but more efficiently.
# return _csr_extract(indices, indptr, jnp.outer(ct, v)), indices, indptr, v
row, col = _csr_to_coo(indices, indptr)
return ct[row] * v[col], indices, indptr, v
def custom_transpose_transpose_rule(cts, *args, call, rule, res_tree, lin_tree,
out_tree):
call_in_tree = treedef_tuple((res_tree, lin_tree))
res_arg, lin_arg = tree_unflatten(call_in_tree, args)
assert all(ad.is_undefined_primal(x) for x in tree_leaves(lin_arg))
assert all(not ad.is_undefined_primal(x) for x in tree_leaves(res_arg))
cts = [
ad_util.zeros_like_aval(ct_aval) if type(ct) is ad_util.Zero else ct
for ct, ct_aval in zip(cts, call.out_avals)
]
ct_out = tree_unflatten(out_tree, cts)
ct_lin = rule(res_arg, ct_out)
ct_lin_flat, ct_lin_tree = tree_flatten(ct_lin)
check_transpose_rule_trees(rule, lin_tree, ct_lin_tree)
return [None] * len(tree_leaves(res_arg)) + ct_lin_flat
def _dynamic_xla_call_transpose(cts_in, *args, jaxpr, num_consts):
# TODO make this a dynamic_xla_call_p bind
del num_consts
vars_to_vals = dict(
(d, t) for v, x in zip(jaxpr.in_binders, args)
if isinstance(v.aval, AbsArray) and not ad.is_undefined_primal(x)
for d, t in zip(v.aval.shape, x.shape) if isinstance(d, Var))
dim_args = [vars_to_vals[v] for v in jaxpr.in_dim_binders]
consts_bar, args_bar = backward_pass(jaxpr, dim_args, args, cts_in) # type: ignore
return [*consts_bar, *args_bar]
def _bcoo_fromdense_transpose(ct, M, *, nse, n_batch, n_dense, index_dtype):
data, indices = ct
n_sparse = M.ndim = n_batch - n_dense
assert data.shape == M.shape[:n_batch] + (nse,) + M.shape[n_batch + n_sparse:]
assert indices.shape == M.shape[:n_batch] + (n_sparse, nse)
assert indices.dtype == index_dtype
if isinstance(indices, ad.Zero):
raise ValueError("Cannot transpose with respect to sparse indices")
assert ad.is_undefined_primal(M)
return bcoo_todense(data, indices, shape=M.aval.shape)
def transposed(*args):
in_primals, out_cts = tree_unflatten(treedef, args)
in_pvals = [pe.PartialVal.unknown(x.aval) if ad.is_undefined_primal(x) else
pe.PartialVal.known(x) for x in in_primals]
primal_fun = lu.wrap_init(partial(core.eval_jaxpr, jaxpr, ()))
tangent_jaxpr, _, consts = pe.trace_to_jaxpr(primal_fun, in_pvals, False)
dummy_args = [ad.UndefinedPrimal(v.aval) for v in tangent_jaxpr.invars]
in_cts_ = ad.backward_pass(tangent_jaxpr, reduce_axes, False, consts, dummy_args,
out_cts)
in_cts, cell.treedef = tree_flatten(in_cts_)
return in_cts
def _linear_call_transpose_rule(cts, *args, callee, transpose,
num_callee_consts,
num_transpose_consts, num_res):
f_consts, t_consts, operands_res, operands_lin = split_list(
args, [num_callee_consts, num_transpose_consts, num_res])
_, _, cts_avals = split_list(
transpose.in_avals, [num_transpose_consts, num_res])
assert all(ad.is_undefined_primal(x) for x in operands_lin)
assert all(not ad.is_undefined_primal(x) for x in operands_res)
cts = [zeros_like_aval(a) if type(ct) is Zero else ct
for ct, a in zip(cts, cts_avals)]
cts_out = linear_call_p.bind(*t_consts, *f_consts, *operands_res, *cts,
callee=transpose,
transpose=callee,
num_callee_consts=len(t_consts),
num_transpose_consts=len(f_consts),
num_res=len(operands_res))
return [None] * (num_callee_consts + num_transpose_consts + num_res) + cts_out
def _bcoo_dot_general_transpose(ct, lhs_data, lhs_indices, rhs, *, dimension_numbers, lhs_shape):
assert not ad.is_undefined_primal(lhs_indices)
if type(ct) is ad.Zero:
return ad.Zero
(lhs_contract, rhs_contract), (lhs_batch, rhs_batch) = dimension_numbers
lhs_ndim = len(lhs_shape)
rhs_ndim = rhs.aval.ndim if ad.is_undefined_primal(rhs) else rhs.ndim
lhs_kept = remaining(range(lhs_ndim), lhs_contract, lhs_batch)
rhs_kept = remaining(range(rhs_ndim), rhs_contract, rhs_batch)
ans_batch, ans_lhs, ans_rhs = ranges_like(lhs_batch, lhs_kept, rhs_kept)
if ad.is_undefined_primal(lhs_data):
dims = ((ans_rhs, rhs_kept), (ans_batch, rhs_batch))
lhs_contract_sorted_by_rhs = list(np.take(lhs_contract, np.argsort(rhs_contract)))
# TODO: extract these sparse indices without constructing the dense matrix.
out_axes = np.argsort(list(lhs_batch) + lhs_kept + lhs_contract_sorted_by_rhs)
out_dense = lax.transpose(lax.dot_general(ct, rhs, dimension_numbers=dims), out_axes)
return bcoo_extract(lhs_indices, out_dense), lhs_indices, rhs
else:
dims = ((lhs_kept, ans_lhs), (lhs_batch, ans_batch))
rhs_contract_sorted_by_lhs = list(np.take(rhs_contract, np.argsort(lhs_contract)))
out_axes = np.argsort(list(rhs_batch) + rhs_contract_sorted_by_lhs + rhs_kept)
result = bcoo_dot_general(lhs_data, lhs_indices, ct, lhs_shape=lhs_shape, dimension_numbers=dims)
return lhs_data, lhs_indices, lax.transpose(result, out_axes)
def _select_and_gather_add_transpose(
t, tangents, operand, *, select_prim, window_dimensions, window_strides,
padding, base_dilation, window_dilation):
assert select_prim in (lax.le_p, lax.ge_p)
assert (ad.is_undefined_primal(tangents) and
not ad.is_undefined_primal(operand))
if any(d != 1 for d in window_dilation):
msg = ("VJP not implemented for select_and_gather (MaxPool) with window "
"dilation, got window_dilation={}.")
raise NotImplementedError(msg.format(window_dilation))
if type(t) is ad_util.Zero:
return [ad_util.Zero(tangents.aval), None]
has_base_dilation = any(d != 1 for d in base_dilation)
if has_base_dilation:
select_identity = (lax._get_max_identity if select_prim is lax.ge_p
else lax._get_min_identity)
operand = lax.pad(operand, select_identity(operand.dtype),
tuple((0, 0, d - 1) for d in base_dilation))
result = _select_and_scatter_add(t, operand, select_prim, window_dimensions,
window_strides, padding)
if has_base_dilation:
result = slicing.slice(result, (0,) * len(result.shape), result.shape,
base_dilation)
return [result, None]
def _linear_solve_transpose_rule(cotangent, *primals, const_lengths, jaxprs):
if jaxprs.transpose_solve is None:
raise TypeError(
'transpose_solve required for backwards mode automatic '
'differentiation of custom_linear_solve')
params, b = _split_linear_solve_args(primals, const_lengths)
# split off symbolic zeros in the cotangent if present
x_cotangent, _ = split_list(cotangent, [len(b)])
assert all(ad.is_undefined_primal(x) for x in b)
cotangent_b_full = linear_solve_p.bind(
*(_flatten(params.transpose()) + x_cotangent),
const_lengths=const_lengths.transpose(),
jaxprs=jaxprs.transpose())
# drop aux values in cotangent computation
cotangent_b, _ = split_list(cotangent_b_full, [len(b)])
return [None] * sum(const_lengths) + cotangent_b
def _reduce_window_sum_transpose_rule(cotangent, operand, *, window_dimensions,
window_strides, padding, base_dilation,
window_dilation):
assert ad.is_undefined_primal(operand)
input_shape = operand.aval.shape
pads = convolution._conv_general_vjp_lhs_padding(
input_shape, window_dimensions, window_strides, cotangent.shape, padding,
base_dilation, window_dilation)
ones = [1] * len(input_shape)
padding_config = [(lo, hi, stride - 1)
for (lo, hi), stride in zip(pads, window_strides)]
pad_cotangent = lax.pad(cotangent, lax._zero(cotangent), padding_config)
result = _reduce_window_sum(pad_cotangent, window_dimensions, base_dilation,
[(0, 0)] * len(input_shape),
base_dilation=ones,
window_dilation=window_dilation)
assert result.shape == input_shape, (result.shape, input_shape)
return [result]
def _bcoo_extract_transpose(ct, indices, mat):
assert ad.is_undefined_primal(mat)
if ad.is_undefined_primal(indices):
raise ValueError("Cannot transpose with respect to sparse indices")
assert ct.dtype == mat.aval.dtype
return indices, bcoo_todense(ct, indices, shape=mat.aval.shape)
def write_primal(v, val):
if not ad.is_undefined_primal(val):
primal_env[v] = val
def abstract(value): return raise_to_shaped(value.aval if ad.is_undefined_primal(value) else get_aval(value))
