# DimensionMismatch error in creating semidefinite constraint in JuMP.jl
**URL:** https://discourse.julialang.org/t/dimensionmismatch-error-in-creating-semidefinite-constraint-in-jump-jl/111969
**Category:** Optimization (Mathematical)
**Tags:** jump
**Created:** [March 22, 2024, 1:03pm UTC](https://discourse.julialang.org/t/dimensionmismatch-error-in-creating-semidefinite-constraint-in-jump-jl/111969 "2024-03-22T13:03:13Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)
#### Post date: [March 22, 2024, 1:03pm UTC](https://discourse.julialang.org/t/dimensionmismatch-error-in-creating-semidefinite-constraint-in-jump-jl/111969/1 "2024-03-22T13:03:13Z")
Dear all,
I have encountered a somewhat unintuitive error in creating the following semidefinte constraint in JuMP.jl. Sample code is as follows:
```julia
# Create a JuMP model
model = Model(optimizer_with_attributes(Mosek.Optimizer))
# Add the variables
@variable(model, G[1:13, 1:13], PSD)
A = [0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 0.0 0.0 0.0 0.0 0.0; 1.0 0.0 0.0 0.0 0.0; 0.0 1.0 0.0 0.0 0.0; 0.0 0.0 1.0 0.0 0.0; 0.0 0.0 0.0 1.0 0.0; 0.0 0.0 0.0 0.0 1.0]
# Want to enforce the constraint -A'GA ⪰ 0
@constraint(model, -A' * G * A >= 0, PSDCone())
```
The last line results in the following error:
```julia
ERROR: DimensionMismatch: array could not be broadcast to match destination
Stacktrace:
[1] check_broadcast_shape
@ .\broadcast.jl:579 [inlined]
[2] check_broadcast_shape
@ .\broadcast.jl:580 [inlined]
[3] check_broadcast_axes
@ .\broadcast.jl:582 [inlined]
[4] instantiate
@ .\broadcast.jl:309 [inlined]
[5] materialize!
@ .\broadcast.jl:914 [inlined]
[6] materialize!
@ .\broadcast.jl:911 [inlined]
[7] operate!(::typeof(*), x::Matrix{AffExpr}, y::Matrix{Float64})
@ MutableArithmetics C:\Users\shuvo\.julia\packages\MutableArithmetics\2vhhw\src\rewrite_generic.jl:9
[8] operate_fallback!!
@ MutableArithmetics C:\Users\username\.julia\packages\MutableArithmetics\2vhhw\src\interface.jl:601 [inlined]
[9] operate!!(::typeof(*), ::Matrix{AffExpr}, ::Matrix{Float64})
@ MutableArithmetics C:\Users\username\.julia\packages\MutableArithmetics\2vhhw\src\interface.jl:585
[10] macro expansion
@ C:\Users\username\.julia\packages\MutableArithmetics\2vhhw\src\rewrite.jl:321 [inlined]
[11] macro expansion
@ C:\Users\username\.julia\packages\JuMP\kSaGf\src\macros.jl:257 [inlined]
[12] macro expansion
@ C:\Users\username\.julia\packages\JuMP\kSaGf\src\macros\@constraint.jl:131 [inlined]
[13] macro expansion
@ C:\Users\username\.julia\packages\JuMP\kSaGf\src\macros.jl:393 [inlined]
[14] top-level scope
@ c:\Users\username\test.jl:147
```
The error goes away if I explicitly describe what `-A` means by rewriting the constraint:
```julia
@constraint(model, ((-1) .* A' * G * A) >= 0, PSDCone())
```
My question is if this `DimensionMismatch` error is expected behavior or not. I would assume that intuitively `JuMP` or `Julia` should interpret `-A` as `(-1).*A`. Please let me know if I am missing something.
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [March 23, 2024, 1:33am UTC](https://discourse.julialang.org/t/dimensionmismatch-error-in-creating-semidefinite-constraint-in-jump-jl/111969/2 "2024-03-23T01:33:23Z")
Hmm there’s a quite serious bug: [Bug in operate!!(\*, A, B) · Issue #271 · jump-dev/MutableArithmetics.jl · GitHub](https://github.com/jump-dev/MutableArithmetics.jl/issues/271)
```Julia
julia> A = [1; 2;;]
2×1 Matrix{Int64}:
1
2
julia> B = [1 2]
1×2 Matrix{Int64}:
1 2
julia> A * B
2×2 Matrix{Int64}:
1 2
2 4
julia> B * A
1×1 Matrix{Int64}:
5
julia> MutableArithmetics.operate!!(*, A, B)
ERROR: DimensionMismatch: array could not be broadcast to match destination
Stacktrace:
[1] check_broadcast_shape
@ ./broadcast.jl:579 [inlined]
[2] check_broadcast_shape
@ ./broadcast.jl:580 [inlined]
[3] check_broadcast_axes
@ ./broadcast.jl:582 [inlined]
[4] instantiate
@ ./broadcast.jl:309 [inlined]
[5] materialize!
@ ./broadcast.jl:914 [inlined]
[6] materialize!
@ ./broadcast.jl:911 [inlined]
[7] operate!(::typeof(*), x::Matrix{Int64}, y::Matrix{Int64})
@ MutableArithmetics ~/.julia/dev/MutableArithmetics/src/rewrite_generic.jl:9
[8] operate_fallback!!
@ ~/.julia/dev/MutableArithmetics/src/interface.jl:601 [inlined]
[9] operate!!(::typeof(*), ::Matrix{Int64}, ::Matrix{Int64})
@ MutableArithmetics ~/.julia/dev/MutableArithmetics/src/interface.jl:585
[10] top-level scope
@ REPL[70]:1
julia> A
2×1 Matrix{Int64}:
1
2
julia> B
1×2 Matrix{Int64}:
1 2
julia> MutableArithmetics.operate!!(*, B, A)
1×2 Matrix{Int64}:
5 5
julia> A
2×1 Matrix{Int64}:
1
2
julia> B
1×2 Matrix{Int64}:
5 5
```
---
### Author:  [@Shuvomoy\_Das\_Gupta](https://discourse.julialang.org/u/Shuvomoy_Das_Gupta)
#### Post date: [March 23, 2024, 8:46pm UTC](https://discourse.julialang.org/t/dimensionmismatch-error-in-creating-semidefinite-constraint-in-jump-jl/111969/3 "2024-03-23T20:46:19Z")
I see, thanks @odow !