# \[PowerModelsDistribution\] Error in indexing during Kron reduction with 1ph loads

**URL:** <https://discourse.julialang.org/t/powermodelsdistribution-error-in-indexing-during-kron-reduction-with-1ph-loads/86900>\
**Category:** Specific Domains\
**Created:** [September 7, 2022, 4:10pm UTC](https://discourse.julialang.org/t/powermodelsdistribution-error-in-indexing-during-kron-reduction-with-1ph-loads/86900 "2022-09-07T16:10:24Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![apigott](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/apigott/32/38583_2.png) [@apigott](https://discourse.julialang.org/u/apigott)\
**Post date:** [September 7, 2022, 4:10pm UTC](https://discourse.julialang.org/t/powermodelsdistribution-error-in-indexing-during-kron-reduction-with-1ph-loads/86900/1 "2022-09-07T16:10:24Z")

</div>

Back again with another question! I’m trying to implement the IEEE-13 bus in PMD and I’m getting an issue with indexing when using the test case defined in the OpenDSS program files.

On import, before adding the vbounds I get the following when calling `calc_start_voltage(data_math_mn["nw"]["0"])` as part of `add_start_vrvi!(data_math_mn);`:

```julia
DimensionMismatch("arrays could not be broadcast to a common size; got a dimension with lengths 3 and 2")

1. <mark> **_bcs1** </mark>@*broadcast.jl:516* [inlined]
2. <mark> **_bcs** </mark>@*broadcast.jl:510* [inlined]
3. <mark> **broadcast_shape** </mark>@*broadcast.jl:504* [inlined]
4. <mark> **combine_axes** </mark>@*broadcast.jl:499* [inlined]
5. <mark> **instantiate** </mark>@*broadcast.jl:281* [inlined]
6. <mark> **materialize** (::Base.Broadcast.Broadcasted{Base.Broadcast.DefaultArrayStyle{1}, Nothing, typeof(*), Tuple{Vector{Float64}, Vector{Any}}})</mark>@*broadcast.jl:860*
7. <mark> **var"#calc_start_voltage#3226"** (::Float64, ::Float64, ::typeof(PowerModelsDistribution.calc_start_voltage), ::Dict{String, Any})</mark>@*transformations.jl:1728*
8. <mark> **calc_start_voltage** </mark>@*transformations.jl:1627* [inlined]
9. <mark> **top-level scope** </mark>@*[Local: 1](http://localhost:1234/edit?id=5fa13d08-2ec4-11ed-2a62-ffda01b116d9#)* [inlined]

```

Since I want to include vbounds anyways I went ahead and tried adding them, but I noticed on `PMD.add_bus_absolute_vbounds!` PMD wants to add the vbounds for the ground conductor as well. Since that doesn’t seem to align with the docs which want vm\_lb and vm\_ub to be of length nphases I tried removing the last vbound for all buses that are grounded. I got this stack trace for the same `calc_start_voltages` command:

```julia
BoundsError: attempt to access 3-element Vector{Float64} at index [4-element BitVector]

    throw_boundserror(::Vector{Float64}, ::Tuple{Base.LogicalIndex{Int64, BitVector}})@abstractarray.jl:691
    checkbounds@abstractarray.jl:656[inlined]
    _getindex@multidimensional.jl:838[inlined]
    getindex(::Vector{Float64}, ::BitVector)@abstractarray.jl:1218
    _apply_filter!(::Dict{String, Any}, ::Vector{String}, ::BitVector)@utils.jl:578
    var"#_apply_kron_reduction!#3130"(::Vector{Int64}, ::Int64, ::typeof(PowerModelsDistribution._apply_kron_reduction!), ::Dict{String, Any})@transformations.jl:374
    var"#apply_pmd!#13"(::Bool, ::Base.Pairs{Symbol, Any, Tuple{Symbol, Symbol}, NamedTuple{(:kr_phases, :kr_neutral), Tuple{Vector{Int64}, Int64}}}, ::typeof(PowerModelsDistribution.apply_pmd!), ::typeof(PowerModelsDistribution._apply_kron_reduction!), ::Dict{String, Any})@data.jl:52
    #apply_kron_reduction!#3129@transformations.jl:356[inlined]
    apply_kron_reduction!(::Dict{String, Any})@transformations.jl:354
    var"#_map_eng2math#3015"(::Bool, ::Bool, ::Vector{Function}, ::Dict{String, Vector{String}}, ::Set{String}, ::typeof(PowerModelsDistribution._map_eng2math), ::Dict{String, Any})@eng2math.jl:188
    var"#transform_data_model#3014"(::Bool, ::Bool, ::Bool, ::Set{String}, ::Dict{String, Vector{String}}, ::Vector{Function}, ::Bool, ::Vector{Function}, ::Bool, ::typeof(PowerModelsDistribution.transform_data_model), ::Dict{String, Any})@eng2math.jl:152
    top-level scope@Local: 1[inlined]

```

So somewhere it seems like it’s trying to access the voltage on the ground (4 conductors) but on a non-grounded 3ph bus. I’m stumped!

Without removing the voltage bounds on the ground conductor I get the exact same stack trace as not calling `PMD.add_bus_absolute_vbounds!` at all so I assume `PMD.add_bus_absolute_vbounds!` is called from `calc_start_voltage` if there aren’t any bounds.

I’m using OpenDSS’s test case implementation of IEEE 13 but I’ve copied it [here](https://drive.google.com/drive/folders/1vI7azdPUoupn3acXU2-QKxb335TlNsnS?usp=sharing) as well

ETA: I didn’t use the PMD.jl IEEE13 implementation because it doesn’t seem to have all the buses – so I’m extremely oblivious to something w/r/t that but it also is giving me the same dimension mismatch issues