ot.stochastic
Stochastic solvers for regularized OT.
Functions
- ot.stochastic.averaged_sgd_entropic_transport(a, b, M, reg, numItermax=300000, lr=None, random_state=None)[source]
Compute the ASGD algorithm to solve the regularized semi continous measures optimal transport max problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg}\cdot\Omega(\gamma)\\s.t. \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the ASGD algorithm as proposed in [18] [alg.2]
- Parameters:
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
numItermax (int) – Number of iteration.
lr (float) – Learning rate.
random_state (int, RandomState instance or None, default=None) – Determines random number generation. Pass an int for reproducible output across multiple function calls.
- Returns:
ave_v (ndarray, shape (nt,)) – dual variable
.. _references-averaged-sgd-entropic-transport
References
- ot.stochastic.batch_grad_dual(a, b, M, reg, alpha, beta, batch_size, batch_alpha, batch_beta)[source]
Computes the partial gradient of the dual optimal transport problem.
For each \((i,j)\) in a batch of coordinates, the partial gradients are :
\[ \begin{align}\begin{aligned}\partial_{\mathbf{u}_i} F = \frac{b_s}{l_v} \mathbf{u}_i - \sum_{j \in B_v} \mathbf{a}_i \mathbf{b}_j \exp\left( \frac{\mathbf{u}_i + \mathbf{v}_j - \mathbf{M}_{i,j}}{\mathrm{reg}} \right)\\\partial_{\mathbf{v}_j} F = \frac{b_s}{l_u} \mathbf{v}_j - \sum_{i \in B_u} \mathbf{a}_i \mathbf{b}_j \exp\left( \frac{\mathbf{u}_i + \mathbf{v}_j - \mathbf{M}_{i,j}}{\mathrm{reg}} \right)\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\mathbf{u}\), \(\mathbf{v}\) are dual variables in \(\mathbb{R}^{ns} \times \mathbb{R}^{nt}\)
reg is the regularization term
\(B_u\) and \(B_v\) are lists of index
\(b_s\) is the size of the batches \(B_u\) and \(B_v\)
\(l_u\) and \(l_v\) are the lengths of \(B_u\) and \(B_v\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the dual problem is the SGD algorithm as proposed in [19] [alg.1]
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
alpha (ndarray, shape (ns,)) – dual variable
beta (ndarray, shape (nt,)) – dual variable
batch_size (int) – size of the batch
batch_alpha (ndarray, shape (bs,)) – batch of index of alpha
batch_beta (ndarray, shape (bs,)) – batch of index of beta
- Returns:
grad (ndarray, shape (ns,)) – partial grad F
.. _references-batch-grad-dual
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.c_transform_entropic(b, M, reg, beta)[source]
The goal is to recover u from the c-transform.
The function computes the c-transform of a dual variable from the other dual variable:
\[\mathbf{u} = \mathbf{v}^{c,reg} = - \mathrm{reg} \sum_j \mathbf{b}_j \exp\left( \frac{\mathbf{v} - \mathbf{M}}{\mathrm{reg}} \right)\]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\mathbf{u}\), \(\mathbf{v}\) are dual variables in \(\mathbb{R}^{ns} \times \mathbb{R}^{nt}\)
reg is the regularization term
It is used to recover an optimal u from optimal v solving the semi dual problem, see Proposition 2.1 of [18]
- Parameters:
b (ndarray, shape (nt,)) – Target measure
M (ndarray, shape (ns, nt)) – Cost matrix
reg (float) – Regularization term > 0
v (ndarray, shape (nt,)) – Dual variable.
- Returns:
u (ndarray, shape (ns,)) – Dual variable.
.. _references-c-transform-entropic
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.coordinate_grad_semi_dual(b, M, reg, beta, i)[source]
Compute the coordinate gradient update for regularized discrete distributions for \((i, :)\)
The function computes the gradient of the semi dual problem:
\[\max_\mathbf{v} \ \sum_i \mathbf{a}_i \left[ \sum_j \mathbf{v}_j \mathbf{b}_j - \mathrm{reg} \cdot \log \left( \sum_j \mathbf{b}_j \exp \left( \frac{\mathbf{v}_j - \mathbf{M}_{i,j}}{\mathrm{reg}} \right) \right) \right]\]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\mathbf{v}\) is a dual variable in \(\mathbb{R}^{nt}\)
reg is the regularization term
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the ASGD & SAG algorithms as proposed in [18] [alg.1 & alg.2]
- Parameters:
- Returns:
coordinate gradient (ndarray, shape (nt,))
.. _references-coordinate-grad-semi-dual
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.loss_dual_entropic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the dual loss of the entropic OT as in equation (6)-(7) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
dual_loss – Dual loss (to maximize)
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
Examples using ot.stochastic.loss_dual_entropic
Dual OT solvers for entropic and quadratic regularized OT with Pytorch
Continuous OT plan estimation with Pytorch
- ot.stochastic.loss_dual_quadratic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the dual loss of the quadratic regularized OT as in equation (6)-(7) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
dual_loss – Dual loss (to maximize)
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
Examples using ot.stochastic.loss_dual_quadratic
Dual OT solvers for entropic and quadratic regularized OT with Pytorch
- ot.stochastic.plan_dual_entropic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the primal OT plan the entropic OT as in equation (8) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
G – Primal OT plan
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
Examples using ot.stochastic.plan_dual_entropic
Dual OT solvers for entropic and quadratic regularized OT with Pytorch
Continuous OT plan estimation with Pytorch
- ot.stochastic.plan_dual_quadratic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the primal OT plan the quadratic regularized OT as in equation (8) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
G – Primal OT plan
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
Examples using ot.stochastic.plan_dual_quadratic
Dual OT solvers for entropic and quadratic regularized OT with Pytorch
- ot.stochastic.sag_entropic_transport(a, b, M, reg, numItermax=10000, lr=None, random_state=None)[source]
Compute the SAG algorithm to solve the regularized discrete measures optimal transport max problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the SAG algorithm as proposed in [18] [alg.1]
- Parameters:
a (ndarray, shape (ns,),) – Source measure.
b (ndarray, shape (nt,),) – Target measure.
M (ndarray, shape (ns, nt),) – Cost matrix.
reg (float) – Regularization term > 0
numItermax (int) – Number of iteration.
lr (float) – Learning rate.
random_state (int, RandomState instance or None, default=None) – Determines random number generation. Pass an int for reproducible output across multiple function calls.
- Returns:
v (ndarray, shape (nt,)) – Dual variable.
.. _references-sag-entropic-transport
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.sgd_entropic_regularization(a, b, M, reg, batch_size, numItermax, lr, random_state=None)[source]
Compute the sgd algorithm to solve the regularized discrete measures optimal transport dual problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
batch_size (int) – size of the batch
numItermax (int) – number of iteration
lr (float) – learning rate
random_state (int, RandomState instance or None, default=None) – Determines random number generation. Pass an int for reproducible output across multiple function calls.
- Returns:
alpha (ndarray, shape (ns,)) – dual variable
beta (ndarray, shape (nt,)) – dual variable
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.solve_dual_entropic(a, b, M, reg, batch_size, numItermax=10000, lr=1, log=False)[source]
Compute the transportation matrix to solve the regularized discrete measures optimal transport dual problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
batch_size (int) – size of the batch
numItermax (int) – number of iteration
lr (float) – learning rate
log (bool, optional) – record log if True
- Returns:
pi (ndarray, shape (ns, nt)) – transportation matrix
log (dict) – log dictionary return only if log==True in parameters
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
Examples using ot.stochastic.solve_dual_entropic
- ot.stochastic.solve_semi_dual_entropic(a, b, M, reg, method, numItermax=10000, lr=None, log=False)[source]
Compute the transportation matrix to solve the regularized discrete measures optimal transport max problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the SAG or ASGD algorithms as proposed in [18]
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
methode (str) – used method (SAG or ASGD)
numItermax (int) – number of iteration
lr (float) – learning rate
n_source (int) – size of the source measure
n_target (int) – size of the target measure
log (bool, optional) – record log if True
- Returns:
pi (ndarray, shape (ns, nt)) – transportation matrix
log (dict) – log dictionary return only if log==True in parameters
.. _references-solve-semi-dual-entropic
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
Examples using ot.stochastic.solve_semi_dual_entropic
- ot.stochastic.averaged_sgd_entropic_transport(a, b, M, reg, numItermax=300000, lr=None, random_state=None)[source]
Compute the ASGD algorithm to solve the regularized semi continous measures optimal transport max problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg}\cdot\Omega(\gamma)\\s.t. \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the ASGD algorithm as proposed in [18] [alg.2]
- Parameters:
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
numItermax (int) – Number of iteration.
lr (float) – Learning rate.
random_state (int, RandomState instance or None, default=None) – Determines random number generation. Pass an int for reproducible output across multiple function calls.
- Returns:
ave_v (ndarray, shape (nt,)) – dual variable
.. _references-averaged-sgd-entropic-transport
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.batch_grad_dual(a, b, M, reg, alpha, beta, batch_size, batch_alpha, batch_beta)[source]
Computes the partial gradient of the dual optimal transport problem.
For each \((i,j)\) in a batch of coordinates, the partial gradients are :
\[ \begin{align}\begin{aligned}\partial_{\mathbf{u}_i} F = \frac{b_s}{l_v} \mathbf{u}_i - \sum_{j \in B_v} \mathbf{a}_i \mathbf{b}_j \exp\left( \frac{\mathbf{u}_i + \mathbf{v}_j - \mathbf{M}_{i,j}}{\mathrm{reg}} \right)\\\partial_{\mathbf{v}_j} F = \frac{b_s}{l_u} \mathbf{v}_j - \sum_{i \in B_u} \mathbf{a}_i \mathbf{b}_j \exp\left( \frac{\mathbf{u}_i + \mathbf{v}_j - \mathbf{M}_{i,j}}{\mathrm{reg}} \right)\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\mathbf{u}\), \(\mathbf{v}\) are dual variables in \(\mathbb{R}^{ns} \times \mathbb{R}^{nt}\)
reg is the regularization term
\(B_u\) and \(B_v\) are lists of index
\(b_s\) is the size of the batches \(B_u\) and \(B_v\)
\(l_u\) and \(l_v\) are the lengths of \(B_u\) and \(B_v\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the dual problem is the SGD algorithm as proposed in [19] [alg.1]
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
alpha (ndarray, shape (ns,)) – dual variable
beta (ndarray, shape (nt,)) – dual variable
batch_size (int) – size of the batch
batch_alpha (ndarray, shape (bs,)) – batch of index of alpha
batch_beta (ndarray, shape (bs,)) – batch of index of beta
- Returns:
grad (ndarray, shape (ns,)) – partial grad F
.. _references-batch-grad-dual
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.c_transform_entropic(b, M, reg, beta)[source]
The goal is to recover u from the c-transform.
The function computes the c-transform of a dual variable from the other dual variable:
\[\mathbf{u} = \mathbf{v}^{c,reg} = - \mathrm{reg} \sum_j \mathbf{b}_j \exp\left( \frac{\mathbf{v} - \mathbf{M}}{\mathrm{reg}} \right)\]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\mathbf{u}\), \(\mathbf{v}\) are dual variables in \(\mathbb{R}^{ns} \times \mathbb{R}^{nt}\)
reg is the regularization term
It is used to recover an optimal u from optimal v solving the semi dual problem, see Proposition 2.1 of [18]
- Parameters:
b (ndarray, shape (nt,)) – Target measure
M (ndarray, shape (ns, nt)) – Cost matrix
reg (float) – Regularization term > 0
v (ndarray, shape (nt,)) – Dual variable.
- Returns:
u (ndarray, shape (ns,)) – Dual variable.
.. _references-c-transform-entropic
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.coordinate_grad_semi_dual(b, M, reg, beta, i)[source]
Compute the coordinate gradient update for regularized discrete distributions for \((i, :)\)
The function computes the gradient of the semi dual problem:
\[\max_\mathbf{v} \ \sum_i \mathbf{a}_i \left[ \sum_j \mathbf{v}_j \mathbf{b}_j - \mathrm{reg} \cdot \log \left( \sum_j \mathbf{b}_j \exp \left( \frac{\mathbf{v}_j - \mathbf{M}_{i,j}}{\mathrm{reg}} \right) \right) \right]\]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\mathbf{v}\) is a dual variable in \(\mathbb{R}^{nt}\)
reg is the regularization term
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the ASGD & SAG algorithms as proposed in [18] [alg.1 & alg.2]
- Parameters:
- Returns:
coordinate gradient (ndarray, shape (nt,))
.. _references-coordinate-grad-semi-dual
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.loss_dual_entropic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the dual loss of the entropic OT as in equation (6)-(7) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
dual_loss – Dual loss (to maximize)
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.loss_dual_quadratic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the dual loss of the quadratic regularized OT as in equation (6)-(7) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
dual_loss – Dual loss (to maximize)
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.plan_dual_entropic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the primal OT plan the entropic OT as in equation (8) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
G – Primal OT plan
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.plan_dual_quadratic(u, v, xs, xt, reg=1, ws=None, wt=None, metric='sqeuclidean')[source]
Compute the primal OT plan the quadratic regularized OT as in equation (8) of [19]
This loss is backend compatible and can be used for stochastic optimization of the dual potentials. It can be used on the full dataset (beware of memory) or on minibatches.
- Parameters:
u (array-like, shape (ns,)) – Source dual potential
v (array-like, shape (nt,)) – Target dual potential
xs (array-like, shape (ns,d)) – Source samples
xt (array-like, shape (ns,d)) – Target samples
reg (float) – Regularization term > 0 (default=1)
ws (array-like, shape (ns,), optional) – Source sample weights (default unif)
wt (array-like, shape (ns,), optional) – Target sample weights (default unif)
metric (string, callable) – Ground metric for OT (default quadratic). Can be given as a callable function taking (xs,xt) as parameters.
- Returns:
G – Primal OT plan
- Return type:
array-like
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.sag_entropic_transport(a, b, M, reg, numItermax=10000, lr=None, random_state=None)[source]
Compute the SAG algorithm to solve the regularized discrete measures optimal transport max problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the SAG algorithm as proposed in [18] [alg.1]
- Parameters:
a (ndarray, shape (ns,),) – Source measure.
b (ndarray, shape (nt,),) – Target measure.
M (ndarray, shape (ns, nt),) – Cost matrix.
reg (float) – Regularization term > 0
numItermax (int) – Number of iteration.
lr (float) – Learning rate.
random_state (int, RandomState instance or None, default=None) – Determines random number generation. Pass an int for reproducible output across multiple function calls.
- Returns:
v (ndarray, shape (nt,)) – Dual variable.
.. _references-sag-entropic-transport
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).
- ot.stochastic.sgd_entropic_regularization(a, b, M, reg, batch_size, numItermax, lr, random_state=None)[source]
Compute the sgd algorithm to solve the regularized discrete measures optimal transport dual problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
batch_size (int) – size of the batch
numItermax (int) – number of iteration
lr (float) – learning rate
random_state (int, RandomState instance or None, default=None) – Determines random number generation. Pass an int for reproducible output across multiple function calls.
- Returns:
alpha (ndarray, shape (ns,)) – dual variable
beta (ndarray, shape (nt,)) – dual variable
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.solve_dual_entropic(a, b, M, reg, batch_size, numItermax=10000, lr=1, log=False)[source]
Compute the transportation matrix to solve the regularized discrete measures optimal transport dual problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
batch_size (int) – size of the batch
numItermax (int) – number of iteration
lr (float) – learning rate
log (bool, optional) – record log if True
- Returns:
pi (ndarray, shape (ns, nt)) – transportation matrix
log (dict) – log dictionary return only if log==True in parameters
References
[19] Seguy, V., Bhushan Damodaran, B., Flamary, R., Courty, N., Rolet, A.& Blondel, M. Large-scale Optimal Transport and Mapping Estimation. International Conference on Learning Representation (2018)
- ot.stochastic.solve_semi_dual_entropic(a, b, M, reg, method, numItermax=10000, lr=None, log=False)[source]
Compute the transportation matrix to solve the regularized discrete measures optimal transport max problem
The function solves the following optimization problem:
\[ \begin{align}\begin{aligned}\gamma = \mathop{\arg \min}_\gamma \quad \langle \gamma, \mathbf{M} \rangle_F + \mathrm{reg} \cdot\Omega(\gamma)\\s.t. \ \gamma \mathbf{1} = \mathbf{a}\\ \gamma^T \mathbf{1} = \mathbf{b}\\ \gamma \geq 0\end{aligned}\end{align} \]Where :
\(\mathbf{M}\) is the (ns, nt) metric cost matrix
\(\Omega\) is the entropic regularization term with \(\Omega(\gamma)=\sum_{i,j} \gamma_{i,j}\log(\gamma_{i,j})\)
\(\mathbf{a}\) and \(\mathbf{b}\) are source and target weights (sum to 1)
The algorithm used for solving the problem is the SAG or ASGD algorithms as proposed in [18]
- Parameters:
a (ndarray, shape (ns,)) – source measure
b (ndarray, shape (nt,)) – target measure
M (ndarray, shape (ns, nt)) – cost matrix
reg (float) – Regularization term > 0
methode (str) – used method (SAG or ASGD)
numItermax (int) – number of iteration
lr (float) – learning rate
n_source (int) – size of the source measure
n_target (int) – size of the target measure
log (bool, optional) – record log if True
- Returns:
pi (ndarray, shape (ns, nt)) – transportation matrix
log (dict) – log dictionary return only if log==True in parameters
.. _references-solve-semi-dual-entropic
References
[18] Genevay, A., Cuturi, M., Peyré, G. & Bach, F. (2016) Stochastic Optimization for Large-scale Optimal Transport. Advances in Neural Information Processing Systems (2016).