Continuous Families

Families of continuous-valued distributions.

families

Parameterized distribution families as continuous morphisms.

Each family is a ContinuousMorphism whose codomain is a continuous space and whose conditional distribution p(y | x) belongs to a specific parametric family. The parameters are learnable functions of x:

  • For discrete domains (FinSet): parameters are looked up from a table.
  • For continuous domains (ContinuousSpace): parameters are produced by a small neural network.

This module wraps every reparameterizable distribution in torch.distributions as a conditional morphism, plus custom families (TruncatedNormal, MultivariateNormal, etc.).

Architecture

Most per-dimension-independent distributions are built on a shared generic base _IndependentConditional that handles the parameter source, transform, and torch.distributions plumbing. The _make_family class factory generates named classes from a specification. Distributions that need special handling (MultivariateNormal, Dirichlet, TruncatedNormal, etc.) are implemented as standalone classes.

ConditionalNormal

ConditionalNormal(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source=None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional normal (Gaussian) distribution.

For each input x, produces an independent normal distribution on each dimension of the codomain:

y_i ~ Normal(mu_i(x), sigma_i(x))

Parameters are learnable: mu and log(sigma) are functions of x, implemented as lookup tables (discrete domain) or neural networks (continuous domain).

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space.

TYPE: Euclidean

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Examples:

>>> from quivers import FinSet
>>> from quivers.continuous.spaces import Euclidean
>>> A = FinSet(name="context", cardinality=5)
>>> Y = Euclidean(name="response", dim=3)
>>> f = ConditionalNormal(A, Y)
>>> x = torch.tensor([0, 1, 2])
>>> samples = f.rsample(x)  # shape (3, 3)
Source code in src/quivers/continuous/families.py
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source=None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    # param_dim = d (mu) + d (log_sigma)
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d

ConditionalLogitNormal

ConditionalLogitNormal(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional logit-normal distribution on (0, 1)^d.

If z ~ Normal(mu(x), sigma(x)), then y = sigmoid(z) ~ LogitNormal. Useful for modeling probabilities and bounded quantities.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (should have bounds [0, 1]).

TYPE: Euclidean

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d

ConditionalBeta

ConditionalBeta(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional beta distribution on (0, 1)^d.

For each input x, produces an independent Beta(alpha_i(x), beta_i(x)) on each dimension of the codomain.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (should have bounds [0, 1]).

TYPE: Euclidean

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d

ConditionalTruncatedNormal

ConditionalTruncatedNormal(domain: AnySpace, codomain: Euclidean, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional truncated normal on [low, high]^d.

A normal distribution restricted to a bounded interval. Uses rejection-free sampling via the inverse CDF (Phi-based) method.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (must be bounded).

TYPE: Euclidean

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
def __init__(
    self,
    domain: AnySpace,
    codomain: Euclidean,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    if codomain.low is None or codomain.high is None:
        raise ValueError("ConditionalTruncatedNormal requires a bounded codomain")

    super().__init__(domain, codomain)
    d = codomain.dim
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d
    self._low = codomain.low
    self._high = codomain.high

ConditionalDirichlet

ConditionalDirichlet(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Dirichlet distribution on a probability simplex.

For each input x, produces a Dirichlet(alpha(x)) distribution on the simplex.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target simplex.

TYPE: Simplex

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self.param_source = _make_source(
        domain,
        d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d

ConditionalUniform

ConditionalUniform(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional uniform distribution on a learnable interval.

Parameterized as Uniform(loc - width/2, loc + width/2) where loc is unconstrained and width is positive. This ensures low < high is always satisfied.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space.

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    # param_dim = d (loc) + d (raw_width)
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d
    # The bounds are data-dependent, so we cannot pin a single
    # interval at construction time; advertise the codomain's
    # declared bounds when available, otherwise fall back to the
    # real line.
    low, high = getattr(codomain, "low", None), getattr(codomain, "high", None)
    if low is not None and high is not None:
        self._support_cache: _constraints.Constraint = _constraints.interval(
            float(low), float(high)
        )
    else:
        self._support_cache = _constraints.real

ConditionalMultivariateNormal

ConditionalMultivariateNormal(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional multivariate normal with full covariance.

Parameterized via Cholesky factor: the parameter source outputs loc (d values) and the lower-triangular entries of L (d*(d+1)/2 values), where Sigma = L @ L^T.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (d-dimensional).

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    n_tril = d * (d + 1) // 2
    self.param_source = _make_source(
        domain,
        d + n_tril,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d
    self._n_tril = n_tril

ConditionalLowRankMVN

ConditionalLowRankMVN(domain: AnySpace, codomain: ContinuousSpace, rank: int = 2, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional low-rank multivariate normal.

Parameterized as loc + low-rank factor + diagonal: Sigma = W @ W^T + diag(d)

This is more parameter-efficient than full MVN for high dimensions.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (d-dimensional).

TYPE: ContinuousSpace

rank

Rank of the low-rank factor W.

TYPE: int DEFAULT: 2

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    rank: int = 2,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self._d = d
    self._rank = rank

    # loc (d) + factor (d * rank) + diag (d)
    total = d + d * rank + d
    self.param_source = _make_source(
        domain,
        total,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalRelaxedBernoulli

ConditionalRelaxedBernoulli(domain: AnySpace, codomain: ContinuousSpace, temperature: float = 0.5, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional relaxed Bernoulli (concrete) distribution.

Outputs continuous values in (0, 1) that approximate Bernoulli samples. The temperature controls the relaxation: lower temperature = closer to discrete.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (should be 1-d per Bernoulli component).

TYPE: ContinuousSpace

temperature

Relaxation temperature.

TYPE: float DEFAULT: 0.5

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    temperature: float = 0.5,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self.param_source = _make_source(
        domain,
        d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d
    self._temperature = temperature

ConditionalRelaxedOneHotCategorical

ConditionalRelaxedOneHotCategorical(domain: AnySpace, codomain: ContinuousSpace, temperature: float = 0.5, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional relaxed one-hot categorical (Gumbel-Softmax).

Outputs continuous vectors on the simplex that approximate one-hot categorical samples.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space (simplex or d-dimensional).

TYPE: ContinuousSpace

temperature

Relaxation temperature.

TYPE: float DEFAULT: 0.5

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    temperature: float = 0.5,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self.param_source = _make_source(
        domain,
        d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d
    self._temperature = temperature

ConditionalWishart

ConditionalWishart(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Wishart distribution over positive-definite matrices.

Produces random d x d positive-definite matrices. Parameterized by degrees of freedom df(x) and a scale matrix V(x).

The codomain dimension is interpreted as d, and outputs are d x d matrices flattened to d^2.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space. dim is the matrix size d (output is d x d).

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    n_tril = d * (d + 1) // 2
    # df (1) + lower-triangular scale (n_tril)
    self.param_source = _make_source(
        domain,
        1 + n_tril,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d
    self._n_tril = n_tril

ConditionalMatrixNormal

ConditionalMatrixNormal(domain: AnySpace, codomain: ContinuousSpace, rows: int, cols: int, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Matrix-Normal :math:\mathcal{MN}(M, U, V).

The matrix-Normal distribution on :math:\mathbb{R}^{n \times p} factorises with a Kronecker-product covariance: if :math:X \sim \mathcal{MN}(M, U, V) then :math:\mathrm{vec}(X) \sim \mathcal{N}(\mathrm{vec}(M), V \otimes U) with :math:U \in \mathbb{R}^{n \times n} the row covariance and :math:V \in \mathbb{R}^{p \times p} the column covariance.

Categorically, the Kronecker structure is the tensor product of two Gaussians; it is strictly more constrained than the flat :math:np-dim MVN that the same parameter tensor could carry, so the surface keeps the two families distinct (no auto-substitution). Use this when the prior should express independent row and column correlation structure.

The codomain's product factorisation supplies the row and column dimensions. The grammar surface ~ MatrixNormal(loc, row_scale, col_scale) over (dom, cod) binds the first axis listed in over to the row covariance and the second to the column covariance.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: AnySpace

codomain

Target space whose factorisation supplies (n, p). Must carry a product structure of two factors; the first is the row axis, the second the column.

TYPE: ContinuousSpace

rows

Row dimension :math:n.

TYPE: int

cols

Column dimension :math:p.

TYPE: int

hidden_dim

Hidden layer width for the parameter network.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    rows: int,
    cols: int,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    self._rows = int(rows)
    self._cols = int(cols)
    n_loc = self._rows * self._cols
    n_row_tril = self._rows * (self._rows + 1) // 2
    n_col_tril = self._cols * (self._cols + 1) // 2
    self._n_loc = n_loc
    self._n_row_tril = n_row_tril
    self._n_col_tril = n_col_tril
    self.param_source = _make_source(
        domain,
        n_loc + n_row_tril + n_col_tril,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalInverseWishart

ConditionalInverseWishart(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Inverse-Wishart over positive-definite matrices.

Conjugate prior for the covariance of a multivariate normal. Realised as a deterministic inversion of a Wishart sample so autograd flows; equivalent in distribution to drawing :math:\Sigma^{-1} \sim \mathcal{W}(\nu, V^{-1}) and inverting. See Gelman et al. (2013) §3.6 for the conjugacy statement.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: AnySpace

codomain

Target space whose dim is the matrix size :math:d.

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for the parameter network.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    n_tril = d * (d + 1) // 2
    self._d = d
    self._n_tril = n_tril
    self.param_source = _make_source(
        domain,
        1 + n_tril,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalBernoulli

ConditionalBernoulli(domain: AnySpace, codomain: AnySpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Bernoulli: continuous probability -> discrete truth value.

Takes a continuous input x and produces learnable logits that parameterize a Bernoulli distribution. The output is a discrete sample in {0, 1}, returned as a LongTensor.

This is the key bridge used in PDS (Grove & White) for the Bern x pattern, where a LogitNormal draw x in (0,1) parameterizes a Bernoulli over truth values.

The codomain must be a FinSet of size 2 (representing {False, True} or {0, 1}).

Note

Sampling from Bernoulli is NOT reparameterizable. Gradients do not flow through the discrete samples. Use score function estimators (REINFORCE) or the Gumbel-Softmax trick if differentiable samples are needed.

PARAMETER DESCRIPTION
domain

Source space (typically UnitInterval or a FinSet).

TYPE: SetObject or ContinuousSpace

codomain

Target FinSet of size 2.

TYPE: SetObject

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
def __init__(
    self,
    domain: AnySpace,
    codomain: AnySpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    from quivers.core.objects import SetObject

    if not isinstance(codomain, SetObject) or codomain.size != 2:
        raise ValueError(
            f"ConditionalBernoulli requires a FinSet(2) codomain, got {codomain!r}"
        )

    super().__init__(domain, codomain)

    # one logit per input
    self.param_source = _make_source(
        domain,
        1,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

log_prob

log_prob(x: Tensor, y: Tensor) -> Tensor

Log-probability of discrete output y given input x.

PARAMETER DESCRIPTION
x

Input tensor.

TYPE: Tensor

y

Discrete output in {0, 1}. Shape (batch,).

TYPE: Tensor

RETURNS DESCRIPTION
Tensor

Log-probabilities. Shape (batch,).

Source code in src/quivers/continuous/families.py
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
def log_prob(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
    """Log-probability of discrete output y given input x.

    Parameters
    ----------
    x : torch.Tensor
        Input tensor.
    y : torch.Tensor
        Discrete output in {0, 1}. Shape (batch,).

    Returns
    -------
    torch.Tensor
        Log-probabilities. Shape (batch,).
    """
    probs = self._get_probs(x)
    dist = D.Bernoulli(probs=probs)
    return dist.log_prob(y.float())

rsample

rsample(x: Tensor, sample_shape: Size = Size()) -> Tensor

Sample from Bernoulli (not reparameterizable).

PARAMETER DESCRIPTION
x

Input tensor.

TYPE: Tensor

sample_shape

Additional leading sample dimensions.

TYPE: Size DEFAULT: Size()

RETURNS DESCRIPTION
Tensor

Discrete samples in {0, 1}. Shape (*sample_shape, batch).

Source code in src/quivers/continuous/families.py
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
def rsample(
    self,
    x: torch.Tensor,
    sample_shape: torch.Size = torch.Size(),
) -> torch.Tensor:
    """Sample from Bernoulli (not reparameterizable).

    Parameters
    ----------
    x : torch.Tensor
        Input tensor.
    sample_shape : torch.Size
        Additional leading sample dimensions.

    Returns
    -------
    torch.Tensor
        Discrete samples in {0, 1}. Shape (*sample_shape, batch).
    """
    probs = self._get_probs(x)
    dist = D.Bernoulli(probs=probs)
    return dist.sample(sample_shape).long()

ConditionalCategorical

ConditionalCategorical(domain: AnySpace, codomain: AnySpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Categorical: continuous input -> discrete category.

Generalizes ConditionalBernoulli to k > 2 categories. Takes a continuous input and produces learnable logits over k categories. The output is a discrete sample in {0, ..., k-1}.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target FinSet of size k.

TYPE: SetObject

hidden_dim

Hidden layer width for neural parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
def __init__(
    self,
    domain: AnySpace,
    codomain: AnySpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    from quivers.core.objects import SetObject

    if not isinstance(codomain, SetObject):
        raise ValueError(
            f"ConditionalCategorical requires a FinSet codomain, got {codomain!r}"
        )

    super().__init__(domain, codomain)
    self._k = codomain.size
    self.param_source = _make_source(
        domain,
        self._k,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

support property

support

Discrete-integer support over {0, …, k-1}.

log_prob

log_prob(x: Tensor, y: Tensor) -> Tensor

Log-probability of discrete output y given input x.

PARAMETER DESCRIPTION
x

Input tensor.

TYPE: Tensor

y

Discrete output in {0, ..., k-1}. Shape (batch,).

TYPE: Tensor

RETURNS DESCRIPTION
Tensor

Log-probabilities. Shape (batch,).

Source code in src/quivers/continuous/families.py
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
def log_prob(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
    """Log-probability of discrete output y given input x.

    Parameters
    ----------
    x : torch.Tensor
        Input tensor.
    y : torch.Tensor
        Discrete output in {0, ..., k-1}. Shape (batch,).

    Returns
    -------
    torch.Tensor
        Log-probabilities. Shape (batch,).
    """
    logits = self._get_logits(x)
    dist = D.Categorical(logits=logits)
    return dist.log_prob(y.long())

rsample

rsample(x: Tensor, sample_shape: Size = Size()) -> Tensor

Sample from Categorical (not reparameterizable).

PARAMETER DESCRIPTION
x

Input tensor.

TYPE: Tensor

sample_shape

Additional leading sample dimensions.

TYPE: Size DEFAULT: Size()

RETURNS DESCRIPTION
Tensor

Discrete samples in {0, ..., k-1}. Shape (*sample_shape, batch).

Source code in src/quivers/continuous/families.py
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
def rsample(
    self,
    x: torch.Tensor,
    sample_shape: torch.Size = torch.Size(),
) -> torch.Tensor:
    """Sample from Categorical (not reparameterizable).

    Parameters
    ----------
    x : torch.Tensor
        Input tensor.
    sample_shape : torch.Size
        Additional leading sample dimensions.

    Returns
    -------
    torch.Tensor
        Discrete samples in {0, ..., k-1}. Shape (*sample_shape, batch).
    """
    logits = self._get_logits(x)
    dist = D.Categorical(logits=logits)
    return dist.sample(sample_shape).long()

ConditionalBinomial

ConditionalBinomial(domain: AnySpace, codomain: ContinuousSpace, total_count: int = 1, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional Binomial(total_count, probs(x)).

The total_count (number of trials) is a fixed hyperparameter set at construction time — typical for binomial likelihoods where n is known per observation. Only the probs parameter is learnable.

Outputs integer counts in {0, 1, ..., total_count}.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space.

TYPE: ContinuousSpace

total_count

Number of Bernoulli trials per observation.

TYPE: int DEFAULT: 1

hidden_dim

Hidden layer width for the parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    total_count: int = 1,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    if total_count < 1:
        raise ValueError(
            f"ConditionalBinomial: total_count must be >= 1, got {total_count}"
        )
    super().__init__(domain, codomain)
    d = codomain.dim
    self._d = d
    self._total_count = int(total_count)
    self.param_source = _make_source(
        domain,
        d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalLogisticNormal

ConditionalLogisticNormal(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional LogisticNormal on the simplex.

Pushes a Normal(loc(x), scale(x)) draw through the softmax transform to produce a simplex-valued sample. Multivariate analogue of ConditionalLogitNormal. Useful as an alternative to ConditionalDirichlet when the underlying simplex distribution should be Gaussian in logit space rather than Beta-shaped.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space; codomain.dim is the simplex dimension.

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for the parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    # We use a Normal in (d-1)-dim space and the
    # StickBreakingTransform to land on the d-simplex.
    # torch.distributions.LogisticNormal handles this.
    self.param_source = _make_source(
        domain,
        2 * (d - 1),
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d

ConditionalOrderedLogistic

ConditionalOrderedLogistic(domain: AnySpace, codomain: AnySpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional OrderedLogistic(predictor(x), cutpoints(x)).

The continuous input drives a parameter source that produces 1 + (K - 1) numbers: one real predictor and a K - 1 cutpoint vector. The cutpoints are passed through a strictly-monotonic transform (first entry free, subsequent entries via cumulative softplus) so the cumulative-link contract c_0 < c_1 < ... < c_{K-2} is satisfied unconditionally.

Outputs integer categories in {0, …, K - 1} where K = codomain.size. The codomain must be a finite set.

Source code in src/quivers/continuous/families.py
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
def __init__(
    self,
    domain: AnySpace,
    codomain: AnySpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    from quivers.core.objects import SetObject

    if not isinstance(codomain, SetObject):
        raise ValueError(
            "ConditionalOrderedLogistic requires a FinSet codomain, "
            f"got {codomain!r}"
        )
    if codomain.size < 2:
        raise ValueError(
            "ConditionalOrderedLogistic requires K >= 2 categories, "
            f"got codomain.size = {codomain.size}"
        )
    super().__init__(domain, codomain)
    self._k = codomain.size
    self.param_source = _make_source(
        domain,
        1 + (self._k - 1),
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalZeroInflatedPoisson

ConditionalZeroInflatedPoisson(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional ZeroInflatedPoisson(zero_prob(x), rate(x)).

The parameter source produces 2 * codomain.dim numbers per input row: the first half feeds a sigmoid to produce the zero-inflation probability, the second half a softplus to produce the Poisson rate. Outputs non-negative integer counts.

Source code in src/quivers/continuous/families.py
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self._d = d
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalHurdlePoisson

ConditionalHurdlePoisson(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional HurdlePoisson(zero_prob(x), rate(x)).

Same parameter shape as ConditionalZeroInflatedPoisson but the two-stage hurdle log-density: a Bernoulli for zero vs positive, then a zero-truncated Poisson for the strictly-positive branch.

Source code in src/quivers/continuous/families.py
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self._d = d
    self.param_source = _make_source(
        domain,
        2 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalZeroOneInflatedBeta

ConditionalZeroOneInflatedBeta(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional ZeroOneInflatedBeta(mu(x), phi(x), zoi(x), coi(x)).

Parameter source emits 4 * dim numbers per row: logit-mu, log-phi, logit-zoi, logit-coi. Used by the runtime family registry for ~ ZeroOneInflatedBeta declarations; formula frontend prefers the inline observe ... <- ZeroOneInflatedBeta(mu, phi, zoi, coi).

Source code in src/quivers/continuous/families.py
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self._d = d
    self.param_source = _make_source(
        domain,
        4 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalMixtureNormal

ConditionalMixtureNormal(domain: AnySpace, codomain: ContinuousSpace, num_components: int = 2, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional finite Gaussian mixture with input-driven weights, locations, and scales.

The parameter source produces 3 * K numbers per row, where K is the number of mixture components (fixed at construction). Weights pass through softmax, locations are emitted directly, scales pass through softplus + epsilon.

The codomain is assumed scalar (1-d real); a higher-dimensional extension would replace Normal with Independent(Normal(...), 1) and triple the per-component parameter count.

Source code in src/quivers/continuous/families.py
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    num_components: int = 2,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    if num_components < 2:
        raise ValueError(
            "ConditionalMixtureNormal: num_components must be >= 2, "
            f"got {num_components}"
        )
    super().__init__(domain, codomain)
    self._k = int(num_components)
    self.param_source = _make_source(
        domain,
        3 * self._k,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalOneHotCategorical

ConditionalOneHotCategorical(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional OneHotCategorical(probs(x)).

Generalises ConditionalCategorical to one-hot encoded outputs (vector of zeros with a single one). Useful as a discrete-output observation kernel where downstream code wants a vector rather than an integer index.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space; codomain.dim is the number of categories.

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for the parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    self._d = d
    self.param_source = _make_source(
        domain,
        d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalMixture

ConditionalMixture(domain: AnySpace, codomain: ContinuousSpace, component_class: type, num_components: int = 4, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

K-component mixture of a conditional family.

Wraps a single conditional family class (one of the registered ConditionalX types) and gives it K independent parameterizations plus learnable mixture logits, producing

p(y | x) = sum_k pi_k(x) * f_k(y | x)

where each f_k is an instance of the component class and pi is the softmax of K learnable logits.

Sampling is via ancestral simulation (Categorical pick + the chosen component's rsample). log_prob evaluates the log-sum-exp of the per-component log-densities. The Categorical pick is non-reparameterizable; gradient flow through the weights uses the score-function path (which higher-level objectives like IWAE can route through).

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space; matches the component family's codomain.

TYPE: ContinuousSpace

component_class

A ConditionalX class accepting (domain, codomain, hidden_dim) constructor args.

TYPE: type

num_components

Number of mixture components.

TYPE: int DEFAULT: 4

hidden_dim

Hidden width for both the mixture-logit MLP and each component's parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    component_class: type,
    num_components: int = 4,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    if num_components < 2:
        raise ValueError(
            f"ConditionalMixture: num_components must be >= 2, got {num_components}"
        )
    super().__init__(domain, codomain)
    self._K = int(num_components)
    self._components = torch.nn.ModuleList(
        [component_class(domain, codomain, hidden_dim) for _ in range(self._K)]
    )
    self.mixture_logits = _make_source(
        domain,
        self._K,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalIndependent

ConditionalIndependent(base: ContinuousMorphism)

Bases: ContinuousMorphism

Reinterpret the trailing batch dimension of a base conditional family as an event dimension.

Equivalent to wrapping the base distribution in torch.distributions.Independent with reinterpreted_batch_ndims = 1. Used to make per-element independence explicit when a downstream guide wants to score a vector-valued observation as a single event.

PARAMETER DESCRIPTION
base

The base conditional family. The wrapped distribution sums the base's per-element log-probabilities along the last axis to score a vector-valued observation.

TYPE: ContinuousMorphism

Source code in src/quivers/continuous/families.py
2357
2358
2359
def __init__(self, base: ContinuousMorphism) -> None:
    super().__init__(base.domain, base.codomain)
    self._base = base

ConditionalTransformed

ConditionalTransformed(base: ContinuousMorphism, transforms: list)

Bases: ContinuousMorphism

A base conditional family composed with a chain of bijectors.

Equivalent to torch.distributions.TransformedDistribution lifted to ContinuousMorphism. The transforms are applied in forward order to rsample outputs; log_prob includes the log-determinant Jacobian correction.

PARAMETER DESCRIPTION
base

Base conditional family.

TYPE: ContinuousMorphism

transforms

Bijectors applied in forward order. Each must implement __call__, inv, and log_abs_det_jacobian.

TYPE: list of torch.distributions.Transform

Source code in src/quivers/continuous/families.py
2399
2400
2401
2402
2403
2404
2405
2406
def __init__(
    self,
    base: ContinuousMorphism,
    transforms: list,
) -> None:
    super().__init__(base.domain, base.codomain)
    self._base = base
    self._transforms = list(transforms)

ConditionalLKJCholesky

ConditionalLKJCholesky(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional LKJCholesky(dim, concentration(x)).

Produces lower-triangular Cholesky factors of correlation matrices on the LKJ distribution (Lewandowski-Kurowicka-Joe 2009, doi:10.1016/j.jmva.2009.04.008). The matrix dimension is taken from codomain.dim; only the concentration parameter is learnable.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space; codomain.dim is the correlation-matrix size.

TYPE: ContinuousSpace

hidden_dim

Hidden layer width for the parameter source.

TYPE: int DEFAULT: None

Source code in src/quivers/continuous/families.py
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    self._matrix_dim = codomain.dim
    self.param_source = _make_source(
        domain,
        1,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )

ConditionalGaussianProcess

ConditionalGaussianProcess(domain: AnySpace, codomain: ContinuousSpace, kernel: str = 'rbf', length_scale: float = 1.0, amplitude: float = 1.0, jitter: float = 1e-06)

Bases: ContinuousMorphism

Gaussian process prior with mean zero and a chosen covariance kernel.

A Gaussian process is a Markov kernel X^N -> G(R^N) whose value at a finite set of input locations x_1, ..., x_N follows a multivariate Normal with covariance matrix K(x_i, x_j). Unlike the parametric families that derive their distribution parameters from a neural network on the input, the GP's "parameters" are the input locations themselves: the kernel function evaluated on the inputs produces the covariance directly.

Reference: Rasmussen & Williams (2006), Gaussian Processes for Machine Learning.

PARAMETER DESCRIPTION
domain

Source space. Its dim is the per-location feature dimensionality D of the inputs.

TYPE: SetObject or ContinuousSpace

codomain

Target space. Its dim is the number of input locations N at which the GP is evaluated.

TYPE: ContinuousSpace

kernel

Covariance kernel. "rbf" is the squared-exponential kernel; "matern52" is the Matern kernel with smoothness nu = 5/2; "linear" is the inner-product kernel.

TYPE: ('rbf', 'matern52', 'linear') DEFAULT: "rbf"

length_scale

Initial length scale of the kernel (positive; learnable). Ignored by the linear kernel.

TYPE: float DEFAULT: 1.0

amplitude

Initial amplitude (positive; learnable). Multiplies the kernel by amplitude^2.

TYPE: float DEFAULT: 1.0

jitter

Diagonal regulariser added to K for numerical positive-definiteness of the Cholesky factorisation.

TYPE: float DEFAULT: 1e-06

Source code in src/quivers/continuous/families.py
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    kernel: str = "rbf",
    length_scale: float = 1.0,
    amplitude: float = 1.0,
    jitter: float = 1e-6,
) -> None:
    super().__init__(domain, codomain)
    if kernel not in _GP_KERNEL_CHOICES:
        raise ValueError(
            f"ConditionalGaussianProcess: unknown kernel {kernel!r}; "
            f"valid choices: {_GP_KERNEL_CHOICES}"
        )
    if length_scale <= 0.0:
        raise ValueError(
            f"ConditionalGaussianProcess: length_scale must be > 0, got {length_scale!r}"
        )
    if amplitude <= 0.0:
        raise ValueError(
            f"ConditionalGaussianProcess: amplitude must be > 0, got {amplitude!r}"
        )
    self._kernel = kernel
    self._jitter = jitter
    self._n = codomain.dim
    self._d = getattr(domain, "dim", None)
    # Store raw (pre-softplus) parameters so the transformed value
    # is strictly positive and the optimiser sees unconstrained
    # variables.
    inv_softplus_ls = math.log(math.expm1(length_scale))
    inv_softplus_amp = math.log(math.expm1(amplitude))
    self._raw_length_scale = torch.nn.Parameter(
        torch.tensor(inv_softplus_ls, dtype=torch.get_default_dtype())
    )
    self._raw_amplitude = torch.nn.Parameter(
        torch.tensor(inv_softplus_amp, dtype=torch.get_default_dtype())
    )

length_scale property

length_scale: Tensor

Current (positive) length scale of the kernel.

amplitude property

amplitude: Tensor

Current (positive) amplitude of the kernel.

ConditionalHorseshoe

ConditionalHorseshoe(domain: AnySpace, codomain: ContinuousSpace, scale: float = 1.0)

Bases: ContinuousMorphism

Carvalho-Polson-Scott horseshoe prior.

The horseshoe prior places a global-local shrinkage structure on each coordinate:

.. code-block:: text

tau ~ HalfCauchy(scale) lambda_d ~ HalfCauchy(1) for d = 1, ..., D beta_d | tau, lambda_d ~ Normal(0, (tau * lambda_d)^2)

The marginal density of beta_d after integrating the local scale lambda_d has no closed form; this implementation uses a 16-point Gauss-Legendre quadrature after mapping the half-line lambda in (0, inf) to t in (0, 1) via the change of variables lambda = tan(pi * t / 2), whose Jacobian is (pi / 2) * sec^2(pi * t / 2).

Reference: Carvalho, Polson & Scott (2010), The horseshoe estimator for sparse signals.

PARAMETER DESCRIPTION
domain

Source space. The prior is conditionally independent of x; x only carries the batch shape.

TYPE: SetObject or ContinuousSpace

codomain

Target space. Its dim is the coordinate count D.

TYPE: ContinuousSpace

scale

Initial global shrinkage tau (positive; learnable).

TYPE: float DEFAULT: 1.0

Source code in src/quivers/continuous/families.py
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    scale: float = 1.0,
) -> None:
    super().__init__(domain, codomain)
    if scale <= 0.0:
        raise ValueError(f"ConditionalHorseshoe: scale must be > 0, got {scale!r}")
    self._d = codomain.dim
    inv_softplus_scale = math.log(math.expm1(scale))
    self._raw_scale = torch.nn.Parameter(
        torch.tensor(inv_softplus_scale, dtype=torch.get_default_dtype())
    )

scale property

scale: Tensor

Current (positive) global shrinkage tau.

ConditionalGeneralizedPareto

ConditionalGeneralizedPareto(domain: AnySpace, codomain: ContinuousSpace, hidden_dim: int | Sequence[int] | None = None, param_source: ParamSource | None = None, param_source_option: str | None = None)

Bases: ContinuousMorphism

Conditional generalized Pareto distribution.

PARAMETER DESCRIPTION
domain

Source space.

TYPE: SetObject or ContinuousSpace

codomain

Target space.

TYPE: ContinuousSpace

hidden_dim

Hidden widths, read only by a source that has hidden layers.

TYPE: int or sequence of int DEFAULT: None

param_source

Select the parameter source directly, or by the DSL's [param_source=...] text.

TYPE: ParamSource | None DEFAULT: None

param_source_option

Select the parameter source directly, or by the DSL's [param_source=...] text.

TYPE: ParamSource | None DEFAULT: None

Source code in src/quivers/continuous/families.py
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
def __init__(
    self,
    domain: AnySpace,
    codomain: ContinuousSpace,
    hidden_dim: int | Sequence[int] | None = None,
    param_source: ParamSource | None = None,
    param_source_option: str | None = None,
) -> None:
    super().__init__(domain, codomain)
    d = codomain.dim
    # loc + scale + concentration
    self.param_source = _make_source(
        domain,
        3 * d,
        hidden_dim,
        param_source=param_source,
        param_source_option=param_source_option,
    )
    self._d = d

LKJCorrelationFactor

LKJCorrelationFactor(dim: int, eta: float, domain: AnySpace)

Bases: ContinuousMorphism

LKJ prior on Cholesky factors LKJ(K, η) over CholeskyFactor(K).

Density on the Cholesky factor:

.. math::

p(L) \propto \prod_{k=2}^{K} L_{kk}^{K - k + 2(\eta - 1)}.

A higher concentration :math:\eta > 1 pulls toward the identity correlation; :math:\eta = 1 is uniform on correlations. Sampling uses the onion method of Lewandowski-Kurowicka-Joe 2009: draw row-norm partial correlations from Beta distributions and form :math:L row-by-row.

PARAMETER DESCRIPTION
dim

Correlation-matrix size :math:K \ge 2.

TYPE: int

eta

Concentration :math:\eta > 0.

TYPE: float

domain

The morphism's source (parameter conditioning); typically the program's input space. The LKJ prior itself does not consume per-observation conditioning, so the rsample path broadcasts the prior across the batch dimension.

TYPE: AnySpace

Source code in src/quivers/continuous/families.py
3285
3286
3287
3288
3289
3290
3291
3292
3293
def __init__(self, dim: int, eta: float, domain: AnySpace) -> None:
    if dim < 2:
        raise ValueError(f"LKJ requires dim >= 2; got {dim}")
    if eta <= 0:
        raise ValueError(f"LKJ requires eta > 0; got {eta}")
    codomain = CholeskyFactor(name=f"L({dim})", dim=dim)
    super().__init__(domain, codomain)
    self._dim = dim
    self._eta = float(eta)

log_prob

log_prob(x: Tensor, y: Tensor) -> Tensor

Log-density of the LKJ prior at the Cholesky factor y.

Up to a normalizing constant that doesn't depend on :math:L, :math:\log p(L) = \sum_{k=2}^{K} (K-k+2(\eta-1)) \log L_{kk}. The diagonal entries are extracted from the flattened representation.

Source code in src/quivers/continuous/families.py
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
def log_prob(self, x: torch.Tensor, y: torch.Tensor) -> torch.Tensor:
    """Log-density of the LKJ prior at the Cholesky factor ``y``.

    Up to a normalizing constant that doesn't depend on
    :math:`L`, :math:`\\log p(L) = \\sum_{k=2}^{K} (K-k+2(\\eta-1))
    \\log L_{kk}`. The diagonal entries are extracted from the
    flattened representation.
    """
    batch = y.shape[0]
    K = self._dim
    L = y.reshape(batch, K, K)
    diag = torch.diagonal(L, dim1=-2, dim2=-1)  # (batch, K)
    # Coefficients per diagonal entry (Stan's lkj_corr_cholesky_lpdf):
    # log_jac_term[k] = (K - k + 2*(eta - 1)) * log(L_kk)  for k = 2..K
    # Pre-K-indexed: power[0..K-1] where power[k] = (K-1-k) + 2*(eta-1).
    # The first diagonal is fixed at 1 so log(1)=0 contributes nothing.
    ks = torch.arange(K, device=y.device, dtype=y.dtype)
    powers = (K - 1 - ks) + 2.0 * (self._eta - 1.0)
    log_diag = torch.log(diag.clamp(min=1e-30))
    return (powers * log_diag).sum(dim=-1)

Truncated

Truncated(base: ContinuousMorphism, lower: float | None = None, upper: float | None = None, max_rejection_iterations: int = 64)

Bases: ContinuousMorphism

Truncate a base family to an interval :math:[a, b].

Categorical denotation: given a base family :math:F : \Theta \to \mathcal{G}(\mathbb{R}) and constants :math:a, b \in \bar{\mathbb{R}} with :math:a < b, the truncated family has density

.. math::

p_{F_{|[a,b]}}(x) = \frac{p_F(x)}{F_{\text{cdf}}(b)
- F_{\text{cdf}}(a)} \cdot \mathbb{1}_{[a,b]}(x)

and the morphism :math:F_{|[a,b]} : \Theta \to \mathcal{G}([a,b]). Sampling uses inverse-CDF when base supports it; otherwise rejection sampling.

PARAMETER DESCRIPTION
base

The base distribution-family morphism. Must expose log_prob and rsample plus an icdf method or a base_distribution torch Distribution for inverse-CDF sampling. Falls back to rejection sampling otherwise.

TYPE: ContinuousMorphism

lower

Lower bound :math:a. None means :math:-\infty.

TYPE: float or None DEFAULT: None

upper

Upper bound :math:b. None means :math:+\infty.

TYPE: float or None DEFAULT: None

max_rejection_iterations

Cap on rejection-sampling attempts before raising.

TYPE: int DEFAULT: 64

Source code in src/quivers/continuous/families.py
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
def __init__(
    self,
    base: ContinuousMorphism,
    lower: float | None = None,
    upper: float | None = None,
    max_rejection_iterations: int = 64,
) -> None:
    super().__init__(base.domain, base.codomain)
    if lower is None and upper is None:
        raise ValueError(
            "Truncated requires at least one of lower / upper to be finite; "
            "without truncation, use the base family directly"
        )
    if lower is not None and upper is not None and not (lower < upper):
        raise ValueError(
            f"Truncated requires lower < upper; got lower={lower}, upper={upper}"
        )
    self._base = base
    self._lower = lower
    self._upper = upper
    self._max_iters = max_rejection_iterations
    # Attach so the parent nn.Module tracks parameters.
    self._base_mod = base