# Release notes

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

## v0.16.0 (May 21, 2024)

This release contains a large number of changes, including some breaking changes. However, despite the large number of changes, most user code should not need to change.

If you encounter an issue updating to this release, please open a GitHub issue, or post on the JuMP community forum: https://jump.dev/forum.

### Breaking

- This release involved a substantial rewrite of Convex.jl to integrate better with MathOptInterface. (#504), (#551), (#584), (#588), (#637)
`x + A`

will error if`x`

is a scalar variable and`A`

is an array. Instead, use`x * ones(size(A)) + A`

.- The
`RelativeEntropyAtom`

now returns a scalar value instead of elementwise values. This does not affect the result of`relative_entropy`

. - The function
`constant`

should be used instead of the type`Constant`

(which now refers to exclusively real constants). - The constraint
`a <= b`

now produces`a - b in Nonpositives()`

instead of`b - a in Nonnegatives()`

. The primal solutions are equivalent, but**the dual variable associated with such constraints is now reversed in sign**. (Following the convention in MathOptInterface, the dual of`a <= b`

is always negative, regardless of optimization sense.) (#593) - The structs
`LtConstraint`

,`GtConstraint`

,`EqConstraint`

`SOCConstraint`

,`ExpConstraint`

,`SDPConstraint`

,`GeoMeanEpiConeConstraint`

,`GeoMeanHypoConeConstraint`

, and`RelativeEntropyEpiCone`

, have been replaced by`Constraint{S}`

where`S<:MOI.AbstractSet`

(#590), (#597), (#598), (#599), (#601), (#602), (#604), (#623), (#632), (#648), (#663), (#665) - The set
`GeomMeanEpiCone`

has been renamed to`GeometricMeanEpiConeSquare`

and`GeomMeanHypoCone`

has been renamed to`GeometricMeanHypoConeSquare`

(#638)

**Subtle breaking change**: scalar row indexing like`x[i, :]`

now produces a column vector instead of a row vector. This better aligns with Julia Base, but it can result in subtle differences, particularly for code like`x[i, :] * y[i, :]'`

: this used to be equivalent to the inner product, but it is now the outer product. In Base Julia, this is the outer product, so the previous code may have been silently broken (#624)- The syntaxes
`dot(*)`

,`dot(/)`

and`dot(^)`

have been removed in favor of explicit broadcasting (`x .* y`

,`x ./ y`

, and`x .^ y`

). These were (mild) type piracy. In addition,`vecdot(x,y)`

has been removed. Call`dot(vec(x), vec(y))`

instead. (#524) - The function
`constraints`

, used to get constraints associated to an individual variable, has been renamed`get_constraints`

(#527) - DCP violations now throw a
`DCPViolationError`

exception, rather than a warning. Relatedly,`Convex.emit_dcp_warnings`

has been removed (#523) - The strict inequalities
`>`

and`<`

have been deprecated. They will be removed in the next breaking release. Note that these never enforced strict inequalities, but instead were equivalent to`>=`

and`<=`

respectively (#555) - The functions
`norm_inf`

,`norm_1`

, and`norm_fro`

have been deprecated. They will be removed in the next breaking release (#567) - The syntax
`x in :PSD`

to create a semidefinite constraint is deprecated and will be removed in the next breaking release (#578) - Fixed setting a
`Constant`

objective function. This is breaking because it now has an objective sense instead of ignoring the objective. (#581) `quadform`

now errors when fixed variables are used instead of silently giving incorrect answers if the value of the fixed variable is modified between solves (#586)- The
`Context`

struct has been refactored and various fields have been changed. The internal details are now considered private. (#645) - The keyword argument
`silent_solver`

has been deprecated to`silent`

. (#670) - Concatenating lists of constraints using
`+`

(and`+=`

) has been deprecated. (#659)

### Added

- SDP, SOC, and exponential cone constraints now have dual values populated (#504)
`geomean`

supports more than 2 arguments (#504)- Added
`Convex.Optimizer`

(#511), (#530), (#534) - Added
`write_to_file`

(#531), (#591) - Added
`entropy_elementwise`

(#570) `norm`

on`AbstractExpr`

objects now supports matrices (treating them like vectors), matching Base's behavior (#528)- Added
`root_det`

(#605) - Added
`VcatAtom`

which is a more efficient implementation of`vcat`

(#607) - Added support for
`SparseArrays.SparseMatrixCSC`

in`Constant`

. This fixed performance problems with some atoms (#631) `solve!`

now reports the time and memory allocation during compilation from the DCP expression graph to MathOptInterface (#633)- Added support for using
`Problem`

as an atom (#646) `show(::IO, ::Problem)`

now includes some problem statistics (#650)`show(::IO, ::Problem)`

now prints less of the expression tree by default (#661)- A new example for quantum conditional entropy has been added. (#671)
`solve!`

now returns the problem itself (#658)

### Fixed

`sumlargesteigs`

now enforces that it's argument is hermitian. (#504)- Type piracy of
`imag`

and`real`

has been removed. This should not affect use of Convex. (#504) - Fix
`dot`

to now correctly complex-conjugates its first argument (#524) - Fixed ambiguities identified by Aqua.jl (#642), (#647)
- Add tests and fix a number of bugs in various atoms (#546), (#547), (#550), (#554), (#556), (#558), (#559), (#561), (#562), (#563), (#565), (#566), (#567), (#568), (#608), (#609), (#617), (#626), (#654), (#655)
- Fixed performance issues in a number of issues related to scalar indexing (#618), (#619), (#620), (#621), (#625), (#634)
- Fixed
`show`

for`Problem`

(#649) `sumsquares`

has a more efficient formulation (#678)- Fixed
`vexity`

of`lieb_ando`

(#684)

### Other

- Improved the documentation (#506), (#517), (#529), (#571), (#573), (#574), (#576), (#579), (#587), (#594), (#628), (#652), (#656), (#666), (#674), (#686)
- Refactored the tests into a functional form (#532)
- Updated
`Project.toml`

(#535) - Added
`test/Project.toml`

(#536) - Refactored imports to explicitly overload methods (#537)
- Tidied and renamed various atoms and files clarity. This should be non-breaking as no public API was changed. (#538), (#539), (#540), (#541), (#543), (#545), (#549), (#553), (#582), (#583)
- Removed the unused file
`src/problem_depot/problems/benchmark.jl`

(#560) - Added various tests to improve code coverage (#522), (#572), (#575), (#577), (#580)
- Updated versions in GitHub actions (#596), (#612), (#629)
- Added license headers (#606)

## v0.15.4 (October 24, 2023)

- Convex's piracy of
`hcat`

and`vcat`

was made less severe, allowing precompilation of Convex.jl on Julia 1.10.

## v0.15.3 (February 11, 2023)

- Add support for LDLFactorizations v0.10 #496.
- Replace
`randn(m, 1)`

with`randn(m)`

to be more Julian #498. - Add support for indexing expressions with
`CartesianIndex`

#500.

## v0.15.2 (August 10, 2022)

- Add support for LDLFactorizations v0.9 #493.
- Fix use of deprecated functions from
`AbstractTrees`

#494.

## v0.15.1 (March 28, 2022)

## v0.15.0 (March 2, 2022)

### Breaking changes

- Minimum required version of Julia is now v1.6
- Updated to MathOptInterface v1.0
- As a consequence, many previously deprecated solver calls may stop working. For example, instead of
`() -> SCS.Optimizer(verbose = 0)`

, use`MOI.OptimizerWithAttributes(SCS.Optimizer, "verbose" => 0)`

.

- As a consequence, many previously deprecated solver calls may stop working. For example, instead of

## v0.14.18 (November 14, 2021)

- Fix typo in
`logisticloss`

for length-1 expressions which caused errors (reported in #458, fixed in #469).

## v0.14.17 (November 14, 2021)

- Updated to become compatible with MathOptInterface v0.10, which enables compatibility with the latest version of many solvers (#467, #468).

## v0.14.16 (September 25, 2021)

- Improve numerical stability when evaluating
`logsumexp`

(#457). Thanks`@JinraeKim`

!

## v0.14.15 (September 15, 2021)

- Use sparse factorization for checking for positive semi-definiteness in
`quadform`

when possible (#457). Thanks`@mtanneau`

! - Add
`assume_psd=false`

argument to skip checking for positive semi-definiteness in`quadform`

(#456).

## v0.14.14 (September 8, 2021)

- Increase the tolerance used in checking if a matrix is positive-semi definite in
`quadform`

(#453). Thanks`@numbermaniac`

!

## v0.14.13 (July 25, 2021)

- fix
`quadform`

for positive semi-definite matrices (fixes a regression introduced in v0.14.11 that required strictly positive semi-definite inputs) #450.

## v0.14.12 (July 19, 2021)

- fix size of result of
`evaluate`

on`IndexAtom`

s #448. Thanks`@hurak`

!

## v0.14.11 (July 5, 2021)

- fix
`quadform`

in the complex case #444. Thanks`@lrnv`

!

## v0.14.10 (May 20, 2021)

- declare compatibility with BenchmarkTools v1.0 #441

## v0.14.9 (May 18, 2021)

- fix some tests in
`lp_dual_abs_atom`

#439. Thanks`@moehle`

!

## v0.14.8 (May 4, 2021)

- a complete port of cvxquad thanks to
`@dstahlke`

, yielding new functions`quantum_relative_entropy`

,`quantum_entropy`

,`trace_logm`

,`trace_mpower`

, and`lieb_ando`

, and cones`GeomMeanHypoCone`

,`GeomMeanEpiCone`

, and`RelativeEntropyEpiCone`

(#418). Thanks a ton for the awesome contribution`@dstahlke`

!

## v0.14.7 (April 22, 2021)

- declare compatibility with BenchmarkTools v0.7 #434

## v0.14.6 (March 28, 2021)

- Use
`MOI.instantiate`

to create the optimizer, which allows users to pass an`MOI.OptimizerWithAttributes`

to configure solver settings #431. Thanks`@odow`

!

## v0.14.5 (March 14, 2021)

- allow
`sumlargest(x,k)`

,`sumsmallest(x,k)`

, and`sumlargesteigs(x,k)`

for`k=0`

(simply returns`Constant(0)`

). (#429).

## v0.14.4 (March 14, 2021)

- fixed a bug where the values of variables were being converted to
`Float64`

even if the problem was solved in high precision. (#427).

## v0.14.3 (March 10, 2021)

- update compatibility bounds for BenchmarkTools 0.6

## v0.14.2 (February 15, 2021)

- added lasso, ridge, and elastic net regression examples (#420). Thanks to
`@PaulSoderlind`

!

## v0.14.1 (January 24, 2021)

- there was a bug causing
`conj`

to act in-place (reported in #416), which has been fixed (#417). This bug appears to have existed since the introduction of`conj`

in Convex.jl v0.5.0.

## v0.14.0 (January 17, 2021)

### Breaking changes

- Changes to the
`sign`

of atoms:- The sign of
`sumlargesteigs`

has been changed from`Positive()`

to`NoSign()`

, to allow non-positive-semidefinite inputs (#409). This has the potential to break code that required that sign to be positive. If you run into this problem, please file an issue so we can figure out a workaround. - The sign of
`eigmin`

and`eigmax`

has been changed from`Positive()`

to`NoSign()`

(#413). This is a bugfix because in general`eigmin`

and`eigmax`

do not need to return a positive quantity (for non-positive-semidefinite inputs). Again, this has the potential to break code that required that sign to be positive. If you run into this problem, please file an issue so we can figure out a workaround.

- The sign of
- Removal of deprecations:
`lambdamin`

and`lambdamax`

has been deprecated to`eigmin`

and`eigmax`

since Convex v0.13.0. This deprecation has been removed, so your code must be updated to call`eigmin`

or`eigmax`

instead (#412).`norm(x, p)`

where`x`

is a matrix expression has been deprecated to`opnorm(x,p)`

since Convex v0.8.0. This deprecation has been removed, so your code must be updated to call`opnorm(x, p)`

instead (#412). Currently,`norm(x,p)`

for a matrix

`x`

will error, but in Convex.jl v0.15.0 it will return`norm(vec(x), p)`

.`Convex.clearmemory()`

has been deprecated and unnecessary since Convex v0.12.5. This deprecation has been removed, so if this function is in your code, just delete it (#412).`vecnorm(x, p)`

has been deprecated to`norm(vec(x), p)`

since Convex v0.8.0. This deprecation has been removed, so your code must be updated to call`norm(vec(x),p)`

instead (#412).

- Other changes:
`Convex.DCP_WARNINGS`

was introduced in Convex v0.13.1 to allow turning off Convex.jl's DCP warnings. This has been removed in favor of the function`Convex.emit_dcp_warnings()`

(Commit 481fa02).

### Other changes

- updated
`nuclearnorm`

and`sumlargesteigs`

to allow complex variables, and allow the argument of`sumlargesteigs`

to be non-positive-semi-definite (#409). Thanks to`@dstahlke`

!

## v0.13.8 (December 2, 2020)

- add unary
`+`

for`Sign`

and`ComplexSign`

to allow single-argument`hcat`

and`vcat`

to work (#405). Thanks to`@dstahlke`

!

## v0.13.7 (September 11, 2020)

- fix #403 by adding the keyword argument
`silent_solver`

to`solve!`

.

## v0.13.6 (September 8, 2020)

- fix #401 by allowing
`diagm(x)`

.

## v0.13.5 (August 25, 2020)

- fix #398 by allowing
`fix!`

'd variables in`quadform`

.

## v0.13.4 (July 27, 2020)

- You can now create your own variable types by subtyping
`AbstractVariable`

. See the docs for more information. You can also add constraints directly to a variable using`add_constraint!`

(#358). - Functions
`vexity(x::Variable)`

,`sign(x::Variable)`

, and`evaluate(x::Variable)`

should now be the preferred way to access properties of a variable; likewise use`set_value!`

to set the initial value of a variable (#358). - To create integer or binary constraints, use the
`VarType`

enum (for example,`Variable(BinVar)`

). Access or set this via`vartype`

and`vartype!`

(#358).

## v0.13.3 (March 22, 2020)

- Make
`add_constraint!`

actually add the constraint to the problem.

## v0.13.2 (March 14, 2020)

- Add
`Convex.MAXDIGITS`

. Thanks to`@riccardomurri`

!

## v0.13.1 (March 6, 2020)

## v0.13.0 (February 28, 2020)

### Major changes

- The intermediate layer has changed from MathProgBase.jl to MathOptInterface.jl (#330). To solve problems, one should pass a MathOptInterface optimizer constructor, such as
`SCS.Optimizer`

, or`MOI.OptimizerWithAttributes(SCS.Optimizer, "verbose" => 0)`

. `lambdamin`

and`lambdamax`

have been deprecated in favor of`eigmin`

and`eigmax`

(#357).- Many "internal" functions and types are no longer exported, such as the atoms, types corresponding to constraints and vexities, etc. (#357).
`evaluate(x::Variable)`

and`evaluate(c::Constant)`

now return scalars and vectors as appropriate, instead of`(1,1)`

- and`(d,1)`

-matrices (#359). This affects functions which used to return`(1,1)`

-matrices; for example, now`evaluate(quadform(...))`

yields a scalar.