# SOS constraints in LP file throwing \`Malformed SOS constraint\` error
**URL:** https://discourse.julialang.org/t/sos-constraints-in-lp-file-throwing-malformed-sos-constraint-error/106324
**Category:** Optimization (Mathematical)
**Tags:** jump
**Created:** [November 16, 2023, 4:21pm UTC](https://discourse.julialang.org/t/sos-constraints-in-lp-file-throwing-malformed-sos-constraint-error/106324 "2023-11-16T16:21:37Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@hdavid16](https://discourse.julialang.org/u/hdavid16)
#### Post date: [November 16, 2023, 4:21pm UTC](https://discourse.julialang.org/t/sos-constraints-in-lp-file-throwing-malformed-sos-constraint-error/106324/1 "2023-11-16T16:21:37Z")
I have a large .lp file exported from CPLEX that I want to read into JuMP with `read_from_file`. However, the SOS constraints are defined in 2 lines each:
```julia
s3: S1 :: x : 1
y : 2
```
As a result, the parsing doesn’t get the second line and says the constraint is malformed. I can manually edit the file to get things on the same line, but perhaps the parsing can be more robust…
Here is where the error gets thrown: (LP.jl)
```julia
function _parse_section(
::typeof(_KW_SOS),
model::Model,
cache::_ReadCache,
line::AbstractString,
)
# SOS constraints can have all manner of whitespace issues with them.
# Normalize them here before attempting to do anything else.
line = replace(line, r"\s+:\s+" => ":")
line = replace(line, r"\s+::" => "::")
tokens = _tokenize(line)
if length(tokens) < 3
error("Malformed SOS constraint: $(line)")
end
```
---
### Author:  [@hdavid16](https://discourse.julialang.org/u/hdavid16)
#### Post date: [November 16, 2023, 4:26pm UTC](https://discourse.julialang.org/t/sos-constraints-in-lp-file-throwing-malformed-sos-constraint-error/106324/2 "2023-11-16T16:26:35Z")
On related note, when the same file gets exported to .mps from CPLEX, `read_from_file` also errors, but for another reason: some variable names have spaces, which results in `ERROR: Malformed COLUMNS line: x!abc def c621198 -1` (variable `x!abc def` has a space). Yes, I know it is bad practice to have a space in a variable name (model is not mine).
---
### Author:  [@odow](https://discourse.julialang.org/u/odow)
#### Post date: [November 16, 2023, 6:58pm UTC](https://discourse.julialang.org/t/sos-constraints-in-lp-file-throwing-malformed-sos-constraint-error/106324/3 "2023-11-16T18:58:47Z")
Urgh. I really just need to write a proper parser for LP files. The current version is a bit of a hack. SOS constraints are non-standard between some implementations, and it doesn’t support spaces in names, (because what sort of name is `x!abc def c621198`).
---
### Author:  [@hdavid16](https://discourse.julialang.org/u/hdavid16)
#### Post date: [November 16, 2023, 7:13pm UTC](https://discourse.julialang.org/t/sos-constraints-in-lp-file-throwing-malformed-sos-constraint-error/106324/4 "2023-11-16T19:13:29Z")
It works well for the most part. Thanks!