From e18ac71772e50203bd0dc72d4bdf42375c89c88b Mon Sep 17 00:00:00 2001
From: Stefan Kroboth <stefan.kroboth@gmail.com>
Date: Thu, 18 Jan 2024 10:21:03 +0100
Subject: [PATCH 1/2] Dedicated crate for `FileCheckpoint`, removed
 `SerializeAlias` and `DeserializeOwnedAlias`

---
 Cargo.toml                                    |  1 +
 argmin/Cargo.toml                             |  4 +-
 argmin/src/core/checkpointing/mod.rs          | 14 ++--
 argmin/src/core/executor.rs                   | 74 +++++++++++++++----
 argmin/src/core/float.rs                      |  6 +-
 argmin/src/core/mod.rs                        |  3 -
 argmin/src/core/serialization.rs              | 53 -------------
 argmin/src/core/solver.rs                     |  2 +-
 argmin/src/solver/conjugategradient/beta.rs   |  4 +-
 argmin/src/solver/conjugategradient/cg.rs     |  5 +-
 .../solver/conjugategradient/nonlinear_cg.rs  | 13 +---
 .../gaussnewton/gaussnewton_linesearch.rs     | 17 ++---
 .../solver/gradientdescent/steepestdescent.rs |  8 +-
 argmin/src/solver/linesearch/backtracking.rs  | 10 +--
 argmin/src/solver/linesearch/hagerzhang.rs    |  8 +-
 argmin/src/solver/linesearch/morethuente.rs   |  8 +-
 argmin/src/solver/neldermead/mod.rs           |  6 +-
 argmin/src/solver/newton/newton_cg.rs         | 11 +--
 argmin/src/solver/particleswarm/mod.rs        |  6 +-
 argmin/src/solver/quasinewton/bfgs.rs         | 24 ++----
 argmin/src/solver/quasinewton/dfp.rs          | 28 ++-----
 argmin/src/solver/quasinewton/lbfgs.rs        | 11 +--
 argmin/src/solver/quasinewton/sr1.rs          | 21 +-----
 .../src/solver/quasinewton/sr1_trustregion.rs | 21 +-----
 argmin/src/solver/simulatedannealing/mod.rs   |  6 +-
 argmin/src/solver/trustregion/steihaug.rs     |  5 +-
 .../solver/trustregion/trustregion_method.rs  | 18 ++---
 checkpointing/file/.gitignore                 |  1 +
 checkpointing/file/Cargo.toml                 | 19 +++++
 .../file.rs => checkpointing/file/src/lib.rs  | 25 ++++---
 examples/checkpoint/.gitignore                |  1 +
 examples/checkpoint/Cargo.toml                |  1 +
 examples/checkpoint/src/main.rs               |  6 +-
 33 files changed, 180 insertions(+), 260 deletions(-)
 delete mode 100644 argmin/src/core/serialization.rs
 create mode 100644 checkpointing/file/.gitignore
 create mode 100644 checkpointing/file/Cargo.toml
 rename argmin/src/core/checkpointing/file.rs => checkpointing/file/src/lib.rs (89%)
 create mode 100644 examples/checkpoint/.gitignore

diff --git a/Cargo.toml b/Cargo.toml
index bd4ca1886..6d8239dcb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -4,6 +4,7 @@ resolver = "2"
 members = [
     "argmin",
     "argmin-math",
+    "checkpointing/*",
     "observers/*",
     "tools/spectator",
 
diff --git a/argmin/Cargo.toml b/argmin/Cargo.toml
index aff79c911..9689846b9 100644
--- a/argmin/Cargo.toml
+++ b/argmin/Cargo.toml
@@ -24,7 +24,6 @@ rand_xoshiro = "0.6.0"
 thiserror = "1.0"
 argmin-math = { path = "../argmin-math", version = "0.3", default-features = false, features = ["primitives"] }
 # optional
-bincode = { version = "1.3.3", optional = true }
 ctrlc = { version = "3.2.4", optional = true }
 getrandom = { version = "0.2", optional = true }
 rayon = { version = "1.6.0", optional = true }
@@ -39,11 +38,12 @@ ndarray-linalg = { version = "0.16", features = ["intel-mkl-static"] }
 argmin-math = { path = "../argmin-math", version = "0.3", features = ["vec"] }
 argmin-observer-slog = { path = "../observers/slog" }
 argmin-observer-paramwriter = { path = "../observers/paramwriter" }
+argmin-checkpointing-file = { path = "../checkpointing/file" }
 
 [features]
 default = []
 wasm-bindgen = ["instant/wasm-bindgen", "getrandom/js"]
-serde1 = ["serde", "bincode", "rand_xoshiro/serde1"]
+serde1 = ["serde", "rand_xoshiro/serde1"]
 _ndarrayl = ["argmin-math/ndarray_latest"]
 # When adding new features, please consider adding them to either `full` (for users)
 # or `_full_dev` (only for local development, testing and computing test coverage).
diff --git a/argmin/src/core/checkpointing/mod.rs b/argmin/src/core/checkpointing/mod.rs
index 51d369e8e..3cd134910 100644
--- a/argmin/src/core/checkpointing/mod.rs
+++ b/argmin/src/core/checkpointing/mod.rs
@@ -12,7 +12,8 @@
 //! with a user-chosen frequency. Optimizations can then be resumed from a given checkpoint after a
 //! crash.
 //!
-//! For saving checkpoints to disk, `FileCheckpoint` is provided.
+//! For saving checkpoints to disk, `FileCheckpoint` is provided in the `argmin-checkpointing-file`
+//! crate.
 //! Via the `Checkpoint` trait other checkpointing approaches can be implemented.
 //!
 //! The `CheckpointingFrequency` defines how often checkpoints are saved and can be chosen to be
@@ -29,7 +30,9 @@
 //! # extern crate argmin_testfunctions;
 //! # use argmin::core::{CostFunction, Error, Executor, Gradient, observers::ObserverMode};
 //! # #[cfg(feature = "serde1")]
-//! # use argmin::core::checkpointing::{FileCheckpoint, CheckpointingFrequency};
+//! use argmin::core::checkpointing::CheckpointingFrequency;
+//! # #[cfg(feature = "serde1")]
+//! use argmin_checkpointing_file::FileCheckpoint;
 //! # use argmin_observer_slog::SlogLogger;
 //! # use argmin::solver::landweber::Landweber;
 //! # use argmin_testfunctions::{rosenbrock_2d, rosenbrock_2d_derivative};
@@ -70,6 +73,7 @@
 //! #
 //! #     let iters = 35;
 //! #     let solver = Landweber::new(0.001);
+//!
 //! // [...]
 //!
 //! # #[cfg(feature = "serde1")]
@@ -98,12 +102,6 @@
 //! # }
 //! ```
 
-#[cfg(feature = "serde1")]
-mod file;
-
-#[cfg(feature = "serde1")]
-pub use crate::core::checkpointing::file::FileCheckpoint;
-
 use crate::core::Error;
 use std::default::Default;
 use std::fmt::Display;
diff --git a/argmin/src/core/executor.rs b/argmin/src/core/executor.rs
index 843b80713..a796f2c4d 100644
--- a/argmin/src/core/executor.rs
+++ b/argmin/src/core/executor.rs
@@ -8,8 +8,7 @@
 use crate::core::checkpointing::Checkpoint;
 use crate::core::observers::{Observe, ObserverMode, Observers};
 use crate::core::{
-    DeserializeOwnedAlias, Error, OptimizationResult, Problem, SerializeAlias, Solver, State,
-    TerminationReason, TerminationStatus, KV,
+    Error, OptimizationResult, Problem, Solver, State, TerminationReason, TerminationStatus, KV,
 };
 use instant;
 use std::sync::atomic::{AtomicBool, Ordering};
@@ -36,7 +35,7 @@ pub struct Executor<O, S, I> {
 impl<O, S, I> Executor<O, S, I>
 where
     S: Solver<O, I>,
-    I: State + SerializeAlias + DeserializeOwnedAlias,
+    I: State,
 {
     /// Constructs an `Executor` from a user defined problem and a solver.
     ///
@@ -313,7 +312,8 @@ where
     /// ```
     /// # use argmin::core::{Error, Executor};
     /// # #[cfg(feature = "serde1")]
-    /// # use argmin::core::checkpointing::{FileCheckpoint, CheckpointingFrequency};
+    /// # use argmin::core::checkpointing::CheckpointingFrequency;
+    /// # use argmin_checkpointing_file::FileCheckpoint;
     /// # use argmin::core::test_utils::{TestSolver, TestProblem};
     /// #
     /// # fn main() -> Result<(), Error> {
@@ -570,17 +570,63 @@ mod tests {
 
     /// The solver's `init` should not be called when started from a checkpoint.
     /// See https://github.com/argmin-rs/argmin/issues/199.
+    // #[cfg(feature = "serde1")]
     #[test]
     #[cfg(feature = "serde1")]
     fn test_checkpointing_solver_initialization() {
-        use crate::core::checkpointing::{CheckpointingFrequency, FileCheckpoint};
-        use crate::core::test_utils::TestProblem;
-        use crate::core::{ArgminFloat, CostFunction};
+        use std::cell::RefCell;
+
+        use crate::core::{
+            checkpointing::CheckpointingFrequency, test_utils::TestProblem, ArgminFloat,
+            CostFunction,
+        };
         use serde::{Deserialize, Serialize};
 
-        // Fake optimization algorithm which holds internal state which changes over time
         #[derive(Clone)]
-        #[cfg_attr(feature = "serde1", derive(Serialize, Deserialize))]
+        pub struct FakeCheckpoint {
+            pub frequency: CheckpointingFrequency,
+            pub solver: RefCell<Option<OptimizationAlgorithm>>,
+            pub state: RefCell<Option<IterState<Vec<f64>, (), (), (), (), f64>>>,
+        }
+
+        impl Checkpoint<OptimizationAlgorithm, IterState<Vec<f64>, (), (), (), (), f64>>
+            for FakeCheckpoint
+        {
+            fn save(
+                &self,
+                solver: &OptimizationAlgorithm,
+                state: &IterState<Vec<f64>, (), (), (), (), f64>,
+            ) -> Result<(), Error> {
+                *self.solver.borrow_mut() = Some(solver.clone());
+                *self.state.borrow_mut() = Some(state.clone());
+                Ok(())
+            }
+
+            fn load(
+                &self,
+            ) -> Result<
+                Option<(
+                    OptimizationAlgorithm,
+                    IterState<Vec<f64>, (), (), (), (), f64>,
+                )>,
+                Error,
+            > {
+                if self.solver.borrow().is_none() {
+                    return Ok(None);
+                }
+                Ok(Some((
+                    self.solver.borrow().clone().unwrap(),
+                    self.state.borrow().clone().unwrap(),
+                )))
+            }
+
+            fn frequency(&self) -> CheckpointingFrequency {
+                self.frequency
+            }
+        }
+
+        // Fake optimization algorithm which holds internal state which changes over time
+        #[derive(Clone, Serialize, Deserialize)]
         struct OptimizationAlgorithm {
             pub internal_state: u64,
         }
@@ -638,12 +684,12 @@ mod tests {
         // solver instance
         let solver = OptimizationAlgorithm { internal_state: 0 };
 
-        // Delete old checkpointing file
-        let _ = std::fs::remove_file(".checkpoints/init_test.arg");
-
         // Create a checkpoint
-        let checkpoint =
-            FileCheckpoint::new(".checkpoints", "init_test", CheckpointingFrequency::Always);
+        let checkpoint = FakeCheckpoint {
+            frequency: CheckpointingFrequency::Always,
+            solver: RefCell::new(None),
+            state: RefCell::new(None),
+        };
 
         // Create and run executor
         let executor = Executor::new(problem, solver)
diff --git a/argmin/src/core/float.rs b/argmin/src/core/float.rs
index 3e98ad555..a2aa24750 100644
--- a/argmin/src/core/float.rs
+++ b/argmin/src/core/float.rs
@@ -5,7 +5,7 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-use crate::core::{kv::KvValue, DeserializeOwnedAlias, SendAlias, SerializeAlias};
+use crate::core::{kv::KvValue, SendAlias};
 use num_traits::{Float, FloatConst, FromPrimitive, ToPrimitive};
 use std::fmt::{Debug, Display};
 
@@ -21,8 +21,6 @@ pub trait ArgminFloat:
     + ToPrimitive
     + Debug
     + Display
-    + SerializeAlias
-    + DeserializeOwnedAlias
     + SendAlias
     + Into<KvValue>
 {
@@ -37,8 +35,6 @@ impl<I> ArgminFloat for I where
         + ToPrimitive
         + Debug
         + Display
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + SendAlias
         + Into<KvValue>
 {
diff --git a/argmin/src/core/mod.rs b/argmin/src/core/mod.rs
index 35918762e..328e186b0 100644
--- a/argmin/src/core/mod.rs
+++ b/argmin/src/core/mod.rs
@@ -29,8 +29,6 @@ mod parallelization;
 mod problem;
 /// Definition of the return type of the solvers
 mod result;
-/// Trait alias for `serde`s `Serialize` and `DeserializeOwned`
-mod serialization;
 /// `Solver` trait
 mod solver;
 /// iteration state
@@ -51,7 +49,6 @@ pub use kv::{KvValue, KV};
 pub use parallelization::{SendAlias, SyncAlias};
 pub use problem::{CostFunction, Gradient, Hessian, Jacobian, LinearProgram, Operator, Problem};
 pub use result::OptimizationResult;
-pub use serialization::{DeserializeOwnedAlias, SerializeAlias};
 pub use solver::Solver;
 pub use state::{IterState, LinearProgramState, PopulationState, State};
 pub use termination::{TerminationReason, TerminationStatus};
diff --git a/argmin/src/core/serialization.rs b/argmin/src/core/serialization.rs
deleted file mode 100644
index d55922029..000000000
--- a/argmin/src/core/serialization.rs
+++ /dev/null
@@ -1,53 +0,0 @@
-// Copyright 2018-2022 argmin developers
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or
-// http://opensource.org/licenses/MIT>, at your option. This file may not be
-// copied, modified, or distributed except according to those terms.
-
-#[cfg(feature = "serde1")]
-use serde::{de::DeserializeOwned, Serialize};
-
-/// Trait alias for `serde`s `Serialize`.
-///
-/// If the `serde1` feature is set, it acts as an alias for `Serialize` and is implemented for all
-/// types which implement `Serialize`. If `serde1` is not set, it will be an "empty" trait
-/// implemented for all types.
-#[cfg(feature = "serde1")]
-pub trait SerializeAlias: Serialize {}
-
-/// Trait alias for `serde`s `Serialize`.
-///
-/// If the `serde1` feature is set, it acts as an alias for `Serialize` and is implemented for all
-/// types which implement `Serialize`. If `serde1` is not set, it will be an "empty" trait
-/// implemented for all types.
-#[cfg(not(feature = "serde1"))]
-pub trait SerializeAlias {}
-
-#[cfg(feature = "serde1")]
-impl<T> SerializeAlias for T where T: Serialize {}
-
-#[cfg(not(feature = "serde1"))]
-impl<T> SerializeAlias for T {}
-
-/// Trait alias for `serde`s `DeserializeOwned`.
-///
-/// If the `serde1` feature is set, it acts as an alias for `DeserializeOwned` and is implemented
-/// for all types which implement `DeserializeOwned`. If `serde1` is not set, it will be an "empty"
-/// trait implemented for all types.
-#[cfg(feature = "serde1")]
-pub trait DeserializeOwnedAlias: DeserializeOwned {}
-
-/// Trait alias for `serde`s `DeserializeOwned`.
-///
-/// If the `serde1` feature is set, it acts as an alias for `DeserializeOwned` and is implemented
-/// for all types which implement `DeserializeOwned`. If `serde1` is not set, it will be an "empty"
-/// trait implemented for all types.
-#[cfg(not(feature = "serde1"))]
-pub trait DeserializeOwnedAlias {}
-
-#[cfg(feature = "serde1")]
-impl<T> DeserializeOwnedAlias for T where T: DeserializeOwned {}
-
-#[cfg(not(feature = "serde1"))]
-impl<T> DeserializeOwnedAlias for T {}
diff --git a/argmin/src/core/solver.rs b/argmin/src/core/solver.rs
index a09915830..dc85df231 100644
--- a/argmin/src/core/solver.rs
+++ b/argmin/src/core/solver.rs
@@ -15,7 +15,7 @@ use crate::core::{Error, Problem, State, TerminationReason, TerminationStatus, K
 /// ([`terminate`](`Solver::terminate`) and [`terminate_internal`](`Solver::terminate_internal`)).
 /// Only `next_iter` is mandatory to implement, all others provide default implementations.
 ///
-/// A `Solver` needs to be serializable.
+/// A `Solver` should be (de)serializable in order to work with checkpointing.
 ///
 /// # Example
 ///
diff --git a/argmin/src/solver/conjugategradient/beta.rs b/argmin/src/solver/conjugategradient/beta.rs
index b3cd3ef99..0fe573564 100644
--- a/argmin/src/solver/conjugategradient/beta.rs
+++ b/argmin/src/solver/conjugategradient/beta.rs
@@ -17,7 +17,7 @@
 //! \[0\] Jorge Nocedal and Stephen J. Wright (2006). Numerical Optimization.
 //! Springer. ISBN 0-387-30303-0.
 
-use crate::core::{ArgminFloat, SerializeAlias};
+use crate::core::ArgminFloat;
 use argmin_math::{ArgminDot, ArgminL2Norm, ArgminSub};
 #[cfg(feature = "serde1")]
 use serde::{Deserialize, Serialize};
@@ -44,7 +44,7 @@ use serde::{Deserialize, Serialize};
 ///     }
 /// }
 /// ```
-pub trait NLCGBetaUpdate<G, P, F>: SerializeAlias {
+pub trait NLCGBetaUpdate<G, P, F> {
     /// Update beta.
     ///
     /// # Parameters
diff --git a/argmin/src/solver/conjugategradient/cg.rs b/argmin/src/solver/conjugategradient/cg.rs
index 2822c6666..59bbdf9db 100644
--- a/argmin/src/solver/conjugategradient/cg.rs
+++ b/argmin/src/solver/conjugategradient/cg.rs
@@ -5,9 +5,7 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-use crate::core::{
-    ArgminFloat, Error, IterState, Operator, Problem, SerializeAlias, Solver, State, KV,
-};
+use crate::core::{ArgminFloat, Error, IterState, Operator, Problem, Solver, State, KV};
 use argmin_math::{ArgminConj, ArgminDot, ArgminL2Norm, ArgminMul, ArgminScaledAdd, ArgminSub};
 #[cfg(feature = "serde1")]
 use serde::{Deserialize, Serialize};
@@ -93,7 +91,6 @@ impl<P, O, F> Solver<O, IterState<P, (), (), (), (), F>> for ConjugateGradient<P
 where
     O: Operator<Param = P, Output = P>,
     P: Clone
-        + SerializeAlias
         + ArgminDot<P, F>
         + ArgminSub<P, P>
         + ArgminScaledAdd<P, F, P>
diff --git a/argmin/src/solver/conjugategradient/nonlinear_cg.rs b/argmin/src/solver/conjugategradient/nonlinear_cg.rs
index c0bc5f686..b1cd80e43 100644
--- a/argmin/src/solver/conjugategradient/nonlinear_cg.rs
+++ b/argmin/src/solver/conjugategradient/nonlinear_cg.rs
@@ -6,8 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    LineSearch, NLCGBetaUpdate, OptimizationResult, Problem, SerializeAlias, Solver, State, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, LineSearch, NLCGBetaUpdate,
+    OptimizationResult, Problem, Solver, State, KV,
 };
 use argmin_math::{ArgminAdd, ArgminDot, ArgminL2Norm, ArgminMul};
 #[cfg(feature = "serde1")]
@@ -122,13 +122,8 @@ impl<O, P, G, L, B, F> Solver<O, IterState<P, G, (), (), (), F>>
     for NonlinearConjugateGradient<P, L, B, F>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    P: Clone + SerializeAlias + DeserializeOwnedAlias + ArgminAdd<P, P> + ArgminMul<F, P>,
-    G: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminMul<F, P>
-        + ArgminDot<G, F>
-        + ArgminL2Norm<F>,
+    P: Clone + ArgminAdd<P, P> + ArgminMul<F, P>,
+    G: Clone + ArgminMul<F, P> + ArgminDot<G, F> + ArgminL2Norm<F>,
     L: Clone + LineSearch<P, F> + Solver<O, IterState<P, G, (), (), (), F>>,
     B: NLCGBetaUpdate<G, P, F>,
     F: ArgminFloat,
diff --git a/argmin/src/solver/gaussnewton/gaussnewton_linesearch.rs b/argmin/src/solver/gaussnewton/gaussnewton_linesearch.rs
index a119a329f..4b49e1ed0 100644
--- a/argmin/src/solver/gaussnewton/gaussnewton_linesearch.rs
+++ b/argmin/src/solver/gaussnewton/gaussnewton_linesearch.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    Jacobian, LineSearch, Operator, OptimizationResult, Problem, SerializeAlias, Solver,
-    TerminationReason, TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, Jacobian, LineSearch,
+    Operator, OptimizationResult, Problem, Solver, TerminationReason, TerminationStatus, KV,
 };
 use argmin_math::{ArgminDot, ArgminInv, ArgminL2Norm, ArgminMul, ArgminTranspose};
 #[cfg(feature = "serde1")]
@@ -84,12 +83,10 @@ impl<L, F: ArgminFloat> GaussNewtonLS<L, F> {
 impl<O, L, F, P, G, J, U, R> Solver<O, IterState<P, G, J, (), R, F>> for GaussNewtonLS<L, F>
 where
     O: Operator<Param = P, Output = U> + Jacobian<Param = P, Jacobian = J>,
-    P: Clone + SerializeAlias + DeserializeOwnedAlias + ArgminMul<F, P>,
-    G: Clone + SerializeAlias + DeserializeOwnedAlias,
+    P: Clone + ArgminMul<F, P>,
+    G: Clone,
     U: ArgminL2Norm<F>,
     J: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + ArgminTranspose<J>
         + ArgminInv<J>
         + ArgminDot<J, J>
@@ -97,7 +94,7 @@ where
         + ArgminDot<U, G>,
     L: Clone + LineSearch<P, F> + Solver<LineSearchProblem<O, F>, IterState<P, G, (), (), R, F>>,
     F: ArgminFloat,
-    R: Clone + SerializeAlias + DeserializeOwnedAlias,
+    R: Clone,
 {
     const NAME: &'static str = "Gauss-Newton method with line search";
 
@@ -196,7 +193,7 @@ impl<O, F> LineSearchProblem<O, F> {
 impl<O, P, F> CostFunction for LineSearchProblem<O, F>
 where
     O: Operator<Param = P, Output = P>,
-    P: Clone + SerializeAlias + DeserializeOwnedAlias + ArgminL2Norm<F>,
+    P: Clone + ArgminL2Norm<F>,
     F: ArgminFloat,
 {
     type Param = P;
@@ -210,7 +207,7 @@ where
 impl<O, P, J, F> Gradient for LineSearchProblem<O, F>
 where
     O: Operator<Param = P, Output = P> + Jacobian<Param = P, Jacobian = J>,
-    P: Clone + SerializeAlias + DeserializeOwnedAlias,
+    P: Clone,
     J: ArgminTranspose<J> + ArgminDot<P, P>,
 {
     type Param = P;
diff --git a/argmin/src/solver/gradientdescent/steepestdescent.rs b/argmin/src/solver/gradientdescent/steepestdescent.rs
index 06f90952e..939ac0668 100644
--- a/argmin/src/solver/gradientdescent/steepestdescent.rs
+++ b/argmin/src/solver/gradientdescent/steepestdescent.rs
@@ -6,8 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    LineSearch, OptimizationResult, Problem, SerializeAlias, Solver, State, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, LineSearch,
+    OptimizationResult, Problem, Solver, State, KV,
 };
 use argmin_math::ArgminMul;
 #[cfg(feature = "serde1")]
@@ -53,8 +53,8 @@ impl<L> SteepestDescent<L> {
 impl<O, L, P, G, F> Solver<O, IterState<P, G, (), (), (), F>> for SteepestDescent<L>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    P: Clone + SerializeAlias + DeserializeOwnedAlias,
-    G: Clone + SerializeAlias + DeserializeOwnedAlias + ArgminMul<F, G>,
+    P: Clone,
+    G: Clone + ArgminMul<F, G>,
     L: Clone + LineSearch<G, F> + Solver<O, IterState<P, G, (), (), (), F>>,
     F: ArgminFloat,
 {
diff --git a/argmin/src/solver/linesearch/backtracking.rs b/argmin/src/solver/linesearch/backtracking.rs
index 8562adcf2..00ffd6e22 100644
--- a/argmin/src/solver/linesearch/backtracking.rs
+++ b/argmin/src/solver/linesearch/backtracking.rs
@@ -6,8 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, Error, Gradient, IterState, LineSearch, Problem, SerializeAlias,
-    Solver, State, TerminationReason, TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Gradient, IterState, LineSearch, Problem, Solver, State,
+    TerminationReason, TerminationStatus, KV,
 };
 use crate::solver::linesearch::condition::*;
 use argmin_math::ArgminScaledAdd;
@@ -177,10 +177,10 @@ where
 
 impl<O, P, G, L, F> Solver<O, IterState<P, G, (), (), (), F>> for BacktrackingLineSearch<P, G, L, F>
 where
-    P: Clone + SerializeAlias + ArgminScaledAdd<G, F, P>,
-    G: SerializeAlias + ArgminScaledAdd<G, F, G>,
+    P: Clone + ArgminScaledAdd<G, F, P>,
+    G: ArgminScaledAdd<G, F, G>,
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    L: LineSearchCondition<G, G, F> + SerializeAlias,
+    L: LineSearchCondition<G, G, F>,
     F: ArgminFloat,
 {
     const NAME: &'static str = "Backtracking line search";
diff --git a/argmin/src/solver/linesearch/hagerzhang.rs b/argmin/src/solver/linesearch/hagerzhang.rs
index 0bdce3b4f..6ebd0f3de 100644
--- a/argmin/src/solver/linesearch/hagerzhang.rs
+++ b/argmin/src/solver/linesearch/hagerzhang.rs
@@ -6,8 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, Error, Gradient, IterState, LineSearch, Problem, SerializeAlias,
-    Solver, TerminationReason, TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Gradient, IterState, LineSearch, Problem, Solver,
+    TerminationReason, TerminationStatus, KV,
 };
 use argmin_math::{ArgminDot, ArgminScaledAdd};
 #[cfg(feature = "serde1")]
@@ -498,8 +498,8 @@ impl<P, G, F> LineSearch<G, F> for HagerZhangLineSearch<P, G, F> {
 impl<P, G, O, F> Solver<O, IterState<P, G, (), (), (), F>> for HagerZhangLineSearch<P, G, F>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    P: Clone + SerializeAlias + ArgminDot<G, F> + ArgminScaledAdd<G, F, P>,
-    G: Clone + SerializeAlias + ArgminDot<G, F>,
+    P: Clone + ArgminDot<G, F> + ArgminScaledAdd<G, F, P>,
+    G: Clone + ArgminDot<G, F>,
     F: ArgminFloat,
 {
     const NAME: &'static str = "Hager-Zhang line search";
diff --git a/argmin/src/solver/linesearch/morethuente.rs b/argmin/src/solver/linesearch/morethuente.rs
index 5351791f3..8fc0a89af 100644
--- a/argmin/src/solver/linesearch/morethuente.rs
+++ b/argmin/src/solver/linesearch/morethuente.rs
@@ -10,8 +10,8 @@
 #![allow(clippy::nonminimal_bool)]
 
 use crate::core::{
-    ArgminFloat, CostFunction, Error, Gradient, IterState, LineSearch, Problem, SerializeAlias,
-    Solver, State, TerminationReason, KV,
+    ArgminFloat, CostFunction, Error, Gradient, IterState, LineSearch, Problem, Solver, State,
+    TerminationReason, KV,
 };
 use argmin_math::{ArgminDot, ArgminScaledAdd};
 #[cfg(feature = "serde1")]
@@ -299,8 +299,8 @@ where
 impl<P, G, O, F> Solver<O, IterState<P, G, (), (), (), F>> for MoreThuenteLineSearch<P, G, F>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    P: Clone + SerializeAlias + ArgminDot<G, F> + ArgminScaledAdd<G, F, P>,
-    G: Clone + SerializeAlias + ArgminDot<G, F>,
+    P: Clone + ArgminDot<G, F> + ArgminScaledAdd<G, F, P>,
+    G: Clone + ArgminDot<G, F>,
     F: ArgminFloat,
 {
     const NAME: &'static str = "More-Thuente Line search";
diff --git a/argmin/src/solver/neldermead/mod.rs b/argmin/src/solver/neldermead/mod.rs
index f530cbd9e..9df22f908 100644
--- a/argmin/src/solver/neldermead/mod.rs
+++ b/argmin/src/solver/neldermead/mod.rs
@@ -19,8 +19,8 @@
 //! <http://www.scholarpedia.org/article/Nelder-Mead_algorithm#Simplex_transformation_algorithm>
 
 use crate::core::{
-    ArgminFloat, CostFunction, Error, IterState, Problem, SerializeAlias, Solver,
-    TerminationReason, TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, IterState, Problem, Solver, TerminationReason,
+    TerminationStatus, KV,
 };
 use argmin_math::{ArgminAdd, ArgminMul, ArgminSub};
 #[cfg(feature = "serde1")]
@@ -319,7 +319,7 @@ impl fmt::Display for Action {
 impl<O, P, F> Solver<O, IterState<P, (), (), (), (), F>> for NelderMead<P, F>
 where
     O: CostFunction<Param = P, Output = F>,
-    P: Clone + SerializeAlias + ArgminSub<P, P> + ArgminAdd<P, P> + ArgminMul<F, P>,
+    P: Clone + ArgminSub<P, P> + ArgminAdd<P, P> + ArgminMul<F, P>,
     F: ArgminFloat + std::iter::Sum<F>,
 {
     const NAME: &'static str = "Nelder-Mead method";
diff --git a/argmin/src/solver/newton/newton_cg.rs b/argmin/src/solver/newton/newton_cg.rs
index c747028d1..2edd12523 100644
--- a/argmin/src/solver/newton/newton_cg.rs
+++ b/argmin/src/solver/newton/newton_cg.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, DeserializeOwnedAlias, Error, Executor, Gradient, Hessian, IterState, LineSearch,
-    Operator, OptimizationResult, Problem, SerializeAlias, Solver, State, TerminationReason,
-    TerminationStatus, KV,
+    ArgminFloat, Error, Executor, Gradient, Hessian, IterState, LineSearch, Operator,
+    OptimizationResult, Problem, Solver, State, TerminationReason, TerminationStatus, KV,
 };
 use crate::solver::conjugategradient::ConjugateGradient;
 use argmin_math::{
@@ -110,16 +109,14 @@ impl<O, L, P, G, H, F> Solver<O, IterState<P, G, (), H, (), F>> for NewtonCG<L,
 where
     O: Gradient<Param = P, Gradient = G> + Hessian<Param = P, Hessian = H>,
     P: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + ArgminSub<P, P>
         + ArgminDot<P, F>
         + ArgminScaledAdd<P, F, P>
         + ArgminMul<F, P>
         + ArgminConj
         + ArgminZeroLike,
-    G: SerializeAlias + DeserializeOwnedAlias + ArgminL2Norm<F> + ArgminMul<F, P>,
-    H: Clone + SerializeAlias + DeserializeOwnedAlias + ArgminDot<P, P>,
+    G: ArgminL2Norm<F> + ArgminMul<F, P>,
+    H: Clone + ArgminDot<P, P>,
     L: Clone + LineSearch<P, F> + Solver<O, IterState<P, G, (), (), (), F>>,
     F: ArgminFloat + ArgminL2Norm<F>,
 {
diff --git a/argmin/src/solver/particleswarm/mod.rs b/argmin/src/solver/particleswarm/mod.rs
index 83a3ef932..40f656096 100644
--- a/argmin/src/solver/particleswarm/mod.rs
+++ b/argmin/src/solver/particleswarm/mod.rs
@@ -21,8 +21,7 @@
 //! \[1\] <https://en.wikipedia.org/wiki/Particle_swarm_optimization>
 
 use crate::core::{
-    ArgminFloat, CostFunction, Error, PopulationState, Problem, SerializeAlias, Solver, SyncAlias,
-    KV,
+    ArgminFloat, CostFunction, Error, PopulationState, Problem, Solver, SyncAlias, KV,
 };
 use argmin_math::{ArgminAdd, ArgminMinMax, ArgminMul, ArgminRandom, ArgminSub, ArgminZeroLike};
 use rand::{Rng, SeedableRng};
@@ -279,8 +278,7 @@ where
 impl<O, P, F, R> Solver<O, PopulationState<Particle<P, F>, F>> for ParticleSwarm<P, F, R>
 where
     O: CostFunction<Param = P, Output = F> + SyncAlias,
-    P: SerializeAlias
-        + Clone
+    P: Clone
         + SyncAlias
         + ArgminAdd<P, P>
         + ArgminSub<P, P>
diff --git a/argmin/src/solver/quasinewton/bfgs.rs b/argmin/src/solver/quasinewton/bfgs.rs
index c1f549c3f..88ce72798 100644
--- a/argmin/src/solver/quasinewton/bfgs.rs
+++ b/argmin/src/solver/quasinewton/bfgs.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    LineSearch, OptimizationResult, Problem, SerializeAlias, Solver, TerminationReason,
-    TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, LineSearch,
+    OptimizationResult, Problem, Solver, TerminationReason, TerminationStatus, KV,
 };
 use argmin_math::{
     ArgminAdd, ArgminDot, ArgminEye, ArgminL2Norm, ArgminMul, ArgminSub, ArgminTranspose,
@@ -134,22 +133,9 @@ where
 impl<O, L, P, G, H, F> Solver<O, IterState<P, G, (), H, (), F>> for BFGS<L, F>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    P: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminSub<P, P>
-        + ArgminDot<G, H>
-        + ArgminDot<P, H>,
-    G: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminL2Norm<F>
-        + ArgminMul<F, P>
-        + ArgminDot<P, F>
-        + ArgminSub<G, G>,
-    H: SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminSub<H, H>
+    P: Clone + ArgminSub<P, P> + ArgminDot<G, H> + ArgminDot<P, H>,
+    G: Clone + ArgminL2Norm<F> + ArgminMul<F, P> + ArgminDot<P, F> + ArgminSub<G, G>,
+    H: ArgminSub<H, H>
         + ArgminDot<G, G>
         + ArgminDot<H, H>
         + ArgminAdd<H, H>
diff --git a/argmin/src/solver/quasinewton/dfp.rs b/argmin/src/solver/quasinewton/dfp.rs
index f4d6ffa57..f3e7bb977 100644
--- a/argmin/src/solver/quasinewton/dfp.rs
+++ b/argmin/src/solver/quasinewton/dfp.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    LineSearch, OptimizationResult, Problem, SerializeAlias, Solver, TerminationReason,
-    TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, LineSearch,
+    OptimizationResult, Problem, Solver, TerminationReason, TerminationStatus, KV,
 };
 use argmin_math::{ArgminAdd, ArgminDot, ArgminL2Norm, ArgminMul, ArgminSub};
 #[cfg(feature = "serde1")]
@@ -99,26 +98,9 @@ where
 impl<O, L, P, G, H, F> Solver<O, IterState<P, G, (), H, (), F>> for DFP<L, F>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
-    P: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminSub<P, P>
-        + ArgminDot<G, F>
-        + ArgminDot<P, H>
-        + ArgminMul<F, P>,
-    G: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminSub<G, G>
-        + ArgminL2Norm<F>
-        + ArgminDot<P, F>,
-    H: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminSub<H, H>
-        + ArgminDot<G, P>
-        + ArgminAdd<H, H>
-        + ArgminMul<F, H>,
+    P: Clone + ArgminSub<P, P> + ArgminDot<G, F> + ArgminDot<P, H> + ArgminMul<F, P>,
+    G: Clone + ArgminSub<G, G> + ArgminL2Norm<F> + ArgminDot<P, F>,
+    H: Clone + ArgminSub<H, H> + ArgminDot<G, P> + ArgminAdd<H, H> + ArgminMul<F, H>,
     L: Clone + LineSearch<P, F> + Solver<O, IterState<P, G, (), (), (), F>>,
     F: ArgminFloat,
 {
diff --git a/argmin/src/solver/quasinewton/lbfgs.rs b/argmin/src/solver/quasinewton/lbfgs.rs
index 7596db603..402eed7a2 100644
--- a/argmin/src/solver/quasinewton/lbfgs.rs
+++ b/argmin/src/solver/quasinewton/lbfgs.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    LineSearch, OptimizationResult, Problem, SerializeAlias, Solver, State, TerminationReason,
-    TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, LineSearch,
+    OptimizationResult, Problem, Solver, State, TerminationReason, TerminationStatus, KV,
 };
 use argmin_math::{
     ArgminAdd, ArgminDot, ArgminL1Norm, ArgminL2Norm, ArgminMinMax, ArgminMul, ArgminSignum,
@@ -306,9 +305,6 @@ impl<O, L, P, G, F> Solver<O, IterState<P, G, (), (), (), F>> for LBFGS<L, P, G,
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
     P: Clone
-        + std::fmt::Debug
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + ArgminSub<P, P>
         + ArgminSub<F, P>
         + ArgminAdd<P, P>
@@ -322,9 +318,6 @@ where
         + ArgminZeroLike
         + ArgminMinMax,
     G: Clone
-        + std::fmt::Debug
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + ArgminL2Norm<F>
         + ArgminSub<G, G>
         + ArgminAdd<G, G>
diff --git a/argmin/src/solver/quasinewton/sr1.rs b/argmin/src/solver/quasinewton/sr1.rs
index 0049d53e3..92ee1a7e4 100644
--- a/argmin/src/solver/quasinewton/sr1.rs
+++ b/argmin/src/solver/quasinewton/sr1.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, IterState,
-    LineSearch, OptimizationResult, Problem, SerializeAlias, Solver, TerminationReason,
-    TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, IterState, LineSearch,
+    OptimizationResult, Problem, Solver, TerminationReason, TerminationStatus, KV,
 };
 use argmin_math::{ArgminAdd, ArgminDot, ArgminL2Norm, ArgminMul, ArgminSub};
 #[cfg(feature = "serde1")]
@@ -149,26 +148,14 @@ impl<O, L, P, G, H, F> Solver<O, IterState<P, G, (), H, (), F>> for SR1<L, F>
 where
     O: CostFunction<Param = P, Output = F> + Gradient<Param = P, Gradient = G>,
     P: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + ArgminSub<P, P>
         + ArgminDot<G, F>
         + ArgminDot<P, F>
         + ArgminDot<P, H>
         + ArgminL2Norm<F>
         + ArgminMul<F, P>,
-    G: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminSub<P, P>
-        + ArgminL2Norm<F>
-        + ArgminSub<G, G>,
-    H: SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminDot<G, P>
-        + ArgminDot<P, P>
-        + ArgminAdd<H, H>
-        + ArgminMul<F, H>,
+    G: Clone + ArgminSub<P, P> + ArgminL2Norm<F> + ArgminSub<G, G>,
+    H: ArgminDot<G, P> + ArgminDot<P, P> + ArgminAdd<H, H> + ArgminMul<F, H>,
     L: Clone + LineSearch<P, F> + Solver<O, IterState<P, G, (), (), (), F>>,
     F: ArgminFloat,
 {
diff --git a/argmin/src/solver/quasinewton/sr1_trustregion.rs b/argmin/src/solver/quasinewton/sr1_trustregion.rs
index 09b92cc70..bb55657e4 100644
--- a/argmin/src/solver/quasinewton/sr1_trustregion.rs
+++ b/argmin/src/solver/quasinewton/sr1_trustregion.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, Hessian,
-    IterState, OptimizationResult, Problem, SerializeAlias, Solver, TerminationReason,
-    TerminationStatus, TrustRegionRadius, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, Hessian, IterState, OptimizationResult,
+    Problem, Solver, TerminationReason, TerminationStatus, TrustRegionRadius, KV,
 };
 use argmin_math::{
     ArgminAdd, ArgminDot, ArgminL2Norm, ArgminMul, ArgminSub, ArgminWeightedDot, ArgminZeroLike,
@@ -186,26 +185,14 @@ where
         + Gradient<Param = P, Gradient = G>
         + Hessian<Param = P, Hessian = B>,
     P: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
         + ArgminSub<P, P>
         + ArgminAdd<P, P>
         + ArgminDot<P, F>
         + ArgminDot<P, B>
         + ArgminL2Norm<F>
         + ArgminZeroLike,
-    G: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminL2Norm<F>
-        + ArgminDot<P, F>
-        + ArgminSub<G, P>,
-    B: Clone
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminDot<P, P>
-        + ArgminAdd<B, B>
-        + ArgminMul<F, B>,
+    G: Clone + ArgminL2Norm<F> + ArgminDot<P, F> + ArgminSub<G, P>,
+    B: Clone + ArgminDot<P, P> + ArgminAdd<B, B> + ArgminMul<F, B>,
     R: Clone + TrustRegionRadius<F> + Solver<O, IterState<P, G, (), B, (), F>>,
     F: ArgminFloat + ArgminL2Norm<F>,
 {
diff --git a/argmin/src/solver/simulatedannealing/mod.rs b/argmin/src/solver/simulatedannealing/mod.rs
index d677739e5..e720f03c7 100644
--- a/argmin/src/solver/simulatedannealing/mod.rs
+++ b/argmin/src/solver/simulatedannealing/mod.rs
@@ -19,8 +19,8 @@
 //! DOI: 10.1126/science.220.4598.671
 
 use crate::core::{
-    ArgminFloat, CostFunction, Error, IterState, Problem, SerializeAlias, Solver,
-    TerminationReason, TerminationStatus, KV,
+    ArgminFloat, CostFunction, Error, IterState, Problem, Solver, TerminationReason,
+    TerminationStatus, KV,
 };
 use rand::prelude::*;
 use rand_xoshiro::Xoshiro256PlusPlus;
@@ -440,7 +440,7 @@ where
     O: CostFunction<Param = P, Output = F> + Anneal<Param = P, Output = P, Float = F>,
     P: Clone,
     F: ArgminFloat,
-    R: Rng + SerializeAlias,
+    R: Rng,
 {
     const NAME: &'static str = "Simulated Annealing";
     fn init(
diff --git a/argmin/src/solver/trustregion/steihaug.rs b/argmin/src/solver/trustregion/steihaug.rs
index 512d9eaf4..cb6134e35 100644
--- a/argmin/src/solver/trustregion/steihaug.rs
+++ b/argmin/src/solver/trustregion/steihaug.rs
@@ -6,8 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, Error, IterState, Problem, SerializeAlias, Solver, State, TerminationReason,
-    TerminationStatus, TrustRegionRadius, KV,
+    ArgminFloat, Error, IterState, Problem, Solver, State, TerminationReason, TerminationStatus,
+    TrustRegionRadius, KV,
 };
 use argmin_math::{
     ArgminAdd, ArgminDot, ArgminL2Norm, ArgminMul, ArgminWeightedDot, ArgminZeroLike,
@@ -181,7 +181,6 @@ where
 impl<P, O, F, H> Solver<O, IterState<P, P, (), H, (), F>> for Steihaug<P, F>
 where
     P: Clone
-        + SerializeAlias
         + ArgminMul<F, P>
         + ArgminL2Norm<F>
         + ArgminDot<P, F>
diff --git a/argmin/src/solver/trustregion/trustregion_method.rs b/argmin/src/solver/trustregion/trustregion_method.rs
index 03e776d47..de1c3a316 100644
--- a/argmin/src/solver/trustregion/trustregion_method.rs
+++ b/argmin/src/solver/trustregion/trustregion_method.rs
@@ -6,9 +6,8 @@
 // copied, modified, or distributed except according to those terms.
 
 use crate::core::{
-    ArgminFloat, CostFunction, DeserializeOwnedAlias, Error, Executor, Gradient, Hessian,
-    IterState, OptimizationResult, Problem, SerializeAlias, Solver, TerminationStatus,
-    TrustRegionRadius, KV,
+    ArgminFloat, CostFunction, Error, Executor, Gradient, Hessian, IterState, OptimizationResult,
+    Problem, Solver, TerminationStatus, TrustRegionRadius, KV,
 };
 use crate::solver::trustregion::reduction_ratio;
 use argmin_math::{ArgminAdd, ArgminDot, ArgminL2Norm, ArgminWeightedDot};
@@ -162,16 +161,9 @@ where
     O: CostFunction<Param = P, Output = F>
         + Gradient<Param = P, Gradient = G>
         + Hessian<Param = P, Hessian = H>,
-    P: Clone
-        + std::fmt::Debug
-        + SerializeAlias
-        + DeserializeOwnedAlias
-        + ArgminL2Norm<F>
-        + ArgminDot<P, F>
-        + ArgminDot<G, F>
-        + ArgminAdd<P, P>,
-    G: Clone + SerializeAlias + DeserializeOwnedAlias,
-    H: Clone + SerializeAlias + DeserializeOwnedAlias + ArgminDot<P, P>,
+    P: Clone + ArgminL2Norm<F> + ArgminDot<P, F> + ArgminDot<G, F> + ArgminAdd<P, P>,
+    G: Clone,
+    H: Clone + ArgminDot<P, P>,
     R: Clone + TrustRegionRadius<F> + Solver<O, IterState<P, G, (), H, (), F>>,
     F: ArgminFloat,
 {
diff --git a/checkpointing/file/.gitignore b/checkpointing/file/.gitignore
new file mode 100644
index 000000000..99c56abe3
--- /dev/null
+++ b/checkpointing/file/.gitignore
@@ -0,0 +1 @@
+.checkpoints
diff --git a/checkpointing/file/Cargo.toml b/checkpointing/file/Cargo.toml
new file mode 100644
index 000000000..6f5c0d706
--- /dev/null
+++ b/checkpointing/file/Cargo.toml
@@ -0,0 +1,19 @@
+[package]
+name = "argmin-checkpointing-file"
+version = "0.1.0"
+authors = ["Stefan Kroboth <stefan.kroboth@gmail.com>"]
+edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "Checkpointing to a file for argmin"
+documentation = "https://docs.rs/argmin-checkpointing-file/"
+homepage = "https://argmin-rs.org"
+repository = "https://github.com/argmin-rs/argmin"
+readme = "README.md"
+keywords = ["optimization", "math", "science"]
+categories = ["science"]
+exclude = []
+
+[dependencies]
+argmin = { version = "0.9.0", path = "../../argmin", default-features = false }
+bincode = "1.3.3"
+serde = "1.0.195"
diff --git a/argmin/src/core/checkpointing/file.rs b/checkpointing/file/src/lib.rs
similarity index 89%
rename from argmin/src/core/checkpointing/file.rs
rename to checkpointing/file/src/lib.rs
index d5d4cebd3..5218910fd 100644
--- a/argmin/src/core/checkpointing/file.rs
+++ b/checkpointing/file/src/lib.rs
@@ -5,8 +5,9 @@
 // http://opensource.org/licenses/MIT>, at your option. This file may not be
 // copied, modified, or distributed except according to those terms.
 
-use crate::core::checkpointing::{Checkpoint, CheckpointingFrequency};
-use crate::core::{DeserializeOwnedAlias, Error, SerializeAlias};
+pub use argmin::core::checkpointing::{Checkpoint, CheckpointingFrequency};
+use argmin::core::Error;
+use serde::{de::DeserializeOwned, Serialize};
 use std::default::Default;
 use std::fs::File;
 use std::io::{BufReader, BufWriter};
@@ -55,7 +56,8 @@ impl FileCheckpoint {
     /// # Example
     ///
     /// ```
-    /// use argmin::core::checkpointing::{FileCheckpoint, CheckpointingFrequency};
+    /// use argmin::core::checkpointing::CheckpointingFrequency;
+    /// use argmin_checkpointing_file::FileCheckpoint;
     /// # use std::path::PathBuf;
     ///
     /// let directory = "checkpoints";
@@ -79,8 +81,8 @@ impl FileCheckpoint {
 
 impl<S, I> Checkpoint<S, I> for FileCheckpoint
 where
-    S: SerializeAlias + DeserializeOwnedAlias,
-    I: SerializeAlias + DeserializeOwnedAlias,
+    S: Serialize + DeserializeOwned,
+    I: Serialize + DeserializeOwned,
 {
     /// Writes checkpoint to disk.
     ///
@@ -91,7 +93,8 @@ where
     /// # Example
     ///
     /// ```
-    /// use argmin::core::checkpointing::{FileCheckpoint, CheckpointingFrequency, Checkpoint};
+    /// use argmin::core::checkpointing::CheckpointingFrequency;
+    /// use argmin_checkpointing_file::FileCheckpoint;
     ///
     /// # use std::fs::File;
     /// # use std::io::BufReader;
@@ -126,7 +129,8 @@ where
     /// # Example
     ///
     /// ```
-    /// use argmin::core::checkpointing::{FileCheckpoint, CheckpointingFrequency, Checkpoint};
+    /// use argmin::core::checkpointing::CheckpointingFrequency;
+    /// use argmin_checkpointing_file::FileCheckpoint
     /// # use argmin::core::Error;
     ///
     /// # use std::fs::File;
@@ -164,18 +168,17 @@ where
 
     /// Returns the how often a checkpoint is to be saved.
     ///
-    /// Used internally by [`save_cond`](`crate::core::checkpointing::Checkpoint::save_cond`).
+    /// Used internally by [`save_cond`](`argmin::core::checkpointing::Checkpoint::save_cond`).
     fn frequency(&self) -> CheckpointingFrequency {
         self.frequency
     }
 }
 
 #[cfg(test)]
-#[cfg(feature = "serde1")]
 mod tests {
     use super::*;
-    use crate::core::test_utils::TestSolver;
-    use crate::core::{IterState, State};
+    use argmin::core::test_utils::TestSolver;
+    use argmin::core::{IterState, State};
 
     #[test]
     #[allow(clippy::type_complexity)]
diff --git a/examples/checkpoint/.gitignore b/examples/checkpoint/.gitignore
new file mode 100644
index 000000000..99c56abe3
--- /dev/null
+++ b/examples/checkpoint/.gitignore
@@ -0,0 +1 @@
+.checkpoints
diff --git a/examples/checkpoint/Cargo.toml b/examples/checkpoint/Cargo.toml
index 436f5e42b..baab731c6 100644
--- a/examples/checkpoint/Cargo.toml
+++ b/examples/checkpoint/Cargo.toml
@@ -7,6 +7,7 @@ publish = false
 
 [dependencies]
 argmin = { version = "*", path = "../../argmin", features = ["serde1"] }
+argmin-checkpointing-file = { version = "*", path = "../../checkpointing/file" }
 argmin-math = { version = "*", features = ["vec"], path = "../../argmin-math" }
 argmin-observer-slog = { version = "*", path = "../../observers/slog/" }
 argmin_testfunctions = "*"
diff --git a/examples/checkpoint/src/main.rs b/examples/checkpoint/src/main.rs
index 9cc014cac..0d1e5e863 100644
--- a/examples/checkpoint/src/main.rs
+++ b/examples/checkpoint/src/main.rs
@@ -7,12 +7,12 @@
 
 use argmin::{
     core::{
-        checkpointing::{CheckpointingFrequency, FileCheckpoint},
-        observers::ObserverMode,
-        CostFunction, Error, Executor, Gradient,
+        checkpointing::CheckpointingFrequency, observers::ObserverMode, CostFunction, Error,
+        Executor, Gradient,
     },
     solver::landweber::Landweber,
 };
+use argmin_checkpointing_file::FileCheckpoint;
 use argmin_observer_slog::SlogLogger;
 use argmin_testfunctions::{rosenbrock_2d, rosenbrock_2d_derivative};
 

From 7d987580b8e73fa5bed9ff6ea4feecbcd57e9d7c Mon Sep 17 00:00:00 2001
From: Stefan Kroboth <stefan.kroboth@gmail.com>
Date: Thu, 18 Jan 2024 12:09:12 +0100
Subject: [PATCH 2/2] Updated actions/cache to v4

---
 .github/workflows/book.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.github/workflows/book.yml b/.github/workflows/book.yml
index c0631bd3c..8da481fd6 100644
--- a/.github/workflows/book.yml
+++ b/.github/workflows/book.yml
@@ -18,7 +18,7 @@ jobs:
 
       - name: Cache dependencies
         id: cache-dependencies
-        uses: actions/cache@v2
+        uses: actions/cache@v4
         with:
           path: |
             ~/.cargo/registry