boundlab.expr.Stack#

class boundlab.expr.Stack[source]#

Bases: Expr

Expression for stacking child expressions along a new dimension.

All children must have identical shapes. The backward pass produces an embed LinearOp per child that places the child at its index along the stacking dimension, with zeros elsewhere.

Methods

`__init__`
`all_subnodes`	Return a list of all sub-expressions in the DAG rooted at this expression, in topological order.
`backward`	Propagate weights to each child via unsqueeze+cat embed ops.
`bound_width`	Compute the width of the bounds for this expression.
`bound_width_reasons_breakdown`	Compute the breakdown of the bound width by reason.
`center`	Compute the center of the bounds for this expression.
`diag`
`expand`
`expand_on`
`flatten`
`flip`
`gather`
`get_const`	Return the concrete tensor if self is a pure constant expression, else None.
`is_symmetric_to_0`	Return True if this expression is symmetric about zero, else False.
`lb`	Compute a lower bound for this expression.
`max_bound_width`	Compute the maximum width across all output dimensions.
`mean`
`narrow`
`permute`
`repeat`
`replace_subnode_once`	Return a new expression with the same structure but sub-expressions replaced by replace_fn.
`reshape`
`roll`
`scatter`
`simplify_ops_`	Recursively compute simplified ops for affine expressions.
`split_const`	Decompose this expression into a constant part and a zero-constant part.
`squeeze`
`sum`
`tile`
`to_string`	Return string representation with child strings substituted.
`transpose`
`ub`	Compute an upper bound for this expression.
`ublb`	Compute both an upper bound and a lower bound for this expression.
`uncertainty_reasons`	Compute the breakdown of the bound width by reason, aggregated to total contributions.
`unflatten`
`unsqueeze`
`with_children`	Return a new expression with the same type and flags but new children.
`zeros_set`

__init__(*children, dim=0)[source]#

property shape: torch.Size#: The shape of the output(s) produced by this expression.

property children: tuple[Expr, ...]#: The child expressions that serve as inputs to this expression.

with_children(*new_children)[source]#

Return a new expression with the same type and flags but new children.

backward(weights, direction='==')[source]#

Propagate weights to each child via unsqueeze+cat embed ops.

Parameters:

weights – A EinsumOp accumulated weight.
direction (Literal['>=', '<=', '==']) – Unused (Stack is always linear).

Returns:

(0, [child_weight_0, child_weight_1, ...])

to_string(*children_str)[source]#

Return string representation with child strings substituted.

property T: Expr#: Convenience for transpose of the last two dimensions.

__add__(other)#

__mul__(other)#: Element-wise multiplication (no broadcast).

all_subnodes()#

Return a list of all sub-expressions in the DAG rooted at this expression, in topological order.

bound_width()#

Compute the width of the bounds for this expression.

bound_width_reasons_breakdown()#

Compute the breakdown of the bound width by reason.

center()#

Compute the center of the bounds for this expression.

diag(diagonal=0)#

expand(*sizes)#

expand_on(dim, size)#

flatten(start_dim=0, end_dim=-1)#

flip(dims)#

gather(indices, dim=0)#

get_const()#

Return the concrete tensor if self is a pure constant expression, else None.

Works for ConstVal and any AffineSum that has no symbolic children.

is_symmetric_to_0()#

Return True if this expression is symmetric about zero, else False.

lb()#

Compute a lower bound for this expression.

max_bound_width()#

Compute the maximum width across all output dimensions.

mean(dim=None, keepdim=False)#

narrow(dim, start, length)#

permute(*dims)#

repeat(*sizes)#

replace_subnode_once(replace_fn)#

Return a new expression with the same structure but sub-expressions replaced by replace_fn.

reshape(*shape)#

roll(shifts, dims)#

scatter(indices, output_shape)#

simplify_ops_()#: Recursively compute simplified ops for affine expressions.

split_const()#

Decompose this expression into a constant part and a zero-constant part.

If the expression is symmetric about zero, the constant part is zero. If the expression is a pure constant, the zero-constant part is zero.

Returns:: A tuple (non_const_part, const_part) where exactly one of the two is zero.
Return type:: tuple[Expr | 0, Expr | 0]

squeeze(dim=None)#

sum(dim=None, keepdim=False)#

tile(*sizes)#

transpose(dim0, dim1)#

ub()#

Compute an upper bound for this expression.

ublb()#

Compute both an upper bound and a lower bound for this expression.

uncertainty_reasons()#

Compute the breakdown of the bound width by reason, aggregated to total contributions.

unflatten(dim, sizes)#

unsqueeze(dim)#

zeros_set(output_shape)#

id: int#: Unique identifier for the expression, used for topological sorting.

flags: ExprFlags#: Flags indicating expression properties for optimization.