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merged 2 commits into from
Apr 10, 2025
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[FileFormats.NL] add support for reading binary format #2718

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[FileFormats.NL] add support for reading binary format
odow Apr 9, 2025
36d5aba
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odow Apr 10, 2025
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145 changes: 93 additions & 52 deletions src/FileFormats/NL/read.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@
# in the LICENSE.md file or at https://opensource.org/licenses/MIT.

mutable struct _CacheModel
is_binary::Bool
cache::Vector{UInt8}
variable_type::Vector{_VariableType}
variable_primal::Vector{Float64}
Expand All @@ -17,6 +18,7 @@ mutable struct _CacheModel
sense::MOI.OptimizationSense
function _CacheModel()
return new(
false,
zeros(UInt8, 64),
_VariableType[],
Float64[],
Expand Down Expand Up @@ -95,12 +97,18 @@ function _next_token(::Type{T}, io::IO, cache::Vector{UInt8}) where {T}
end

function _next(::Type{Float64}, io::IO, model::_CacheModel)
if model.is_binary
return read(io, Float64)
end
nnz = _next_token(Float64, io, model.cache)
@assert nnz > 0
return parse(Float64, String(model.cache[1:nnz]))
end

function _next(::Type{Int}, io::IO, model::_CacheModel)
if model.is_binary
return convert(Int, read(io, Int32))
end
nnz = _next_token(Int, io, model.cache)
@assert nnz > 0
y = 0
Expand All @@ -112,13 +120,27 @@ function _next(::Type{Int}, io::IO, model::_CacheModel)
return y
end

function _next(::Type{Cchar}, io::IO, model::_CacheModel)
if model.is_binary
return read(io, Cchar)
end
byte = UInt8(' ')
while byte == UInt8(' ')
byte = read(io, UInt8)
end
return Cchar(byte)
end

"""
_read_til_newline(io::IO)
_read_til_newline(io::IO, model::_CacheModel)

This function reads until it finds a new line character. This is useful for
skipping comments.
"""
function _read_til_newline(io::IO)
function _read_til_newline(io::IO, model::_CacheModel)
if model.is_binary
return
end
while read(io, UInt8) != UInt8('\n')
end
return
Expand All @@ -131,12 +153,12 @@ function _parse_expr(io::IO, model::_CacheModel)
char = Char(read(io, UInt8))
if char == 'o'
opcode = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
arity, op_func = _AMPL_TO_JULIA[opcode]
op_sym = Symbol(op_func)
if arity == -1
arity = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
if op_sym == :sum
op_sym = :+
elseif op_sym == :minimum
Expand All @@ -153,12 +175,12 @@ function _parse_expr(io::IO, model::_CacheModel)
return parent
elseif char == 'v'
index = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
return MOI.VariableIndex(index + 1)
else
@assert char == 'n'
ret = _next(Float64, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
return ret
end
end
Expand Down Expand Up @@ -270,13 +292,16 @@ function _parse_header(io::IO, model::_CacheModel)
# Line 1
# We don't support the binary format.
byte = read(io, UInt8)
if byte != UInt8('g')
is_binary = false
if byte == UInt8('b')
is_binary = true
elseif byte != UInt8('g')
error("Unable to parse NL file : unsupported mode $(Char(byte))")
end
# L1 has some magic bytes for AMPL internals (to quote David, "The numbers
# on the first line matter to AMPL; for other uses, it is best simply to
# supply the ones shown above.")
_read_til_newline(io)
_read_til_newline(io, model)
# Line 2
# The number of variables
n_var = _next(Int, io, model)
Expand All @@ -292,39 +317,39 @@ function _parse_header(io::IO, model::_CacheModel)
# The number of logical constraints. This one is optional, so just read til
# the end of the line.
# @assert _next(Int, io, model) == 0
_read_til_newline(io)
_read_til_newline(io, model)
# Line 3
# The number of nonlinear constraints
@assert _next(Int, io, model) >= 0
# The number of nonlinear objectives
@assert 0 <= _next(Int, io, model) <= 1
_read_til_newline(io)
_read_til_newline(io, model)
# Line 4
# The number of nonlinear network constraints
@assert _next(Int, io, model) == 0
# The number of linear network constraints
@assert _next(Int, io, model) == 0
_read_til_newline(io)
_read_til_newline(io, model)
# Line 5
# The number of nonlienar variables in constraints
nlvc = _next(Int, io, model)
# The number of nonlienar variables in objectives
nlvo = _next(Int, io, model)
# The number of nonlienar variables in constraints and objectives (both)
nlvb = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
# Line 6
# The number of linear network variables
@assert _next(Int, io, model) == 0
# The number of user-defined functions
@assert _next(Int, io, model) == 0
# The number of "arith"
# TODO(odow): I don't know what this is.
@assert _next(Int, io, model) == 0
_next(Int, io, model)
# The "flags" entry. This is mainly used for specifying that we want duals.
# Ignore when reading.
_next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
# Line 7
# Number of binary variables
nbv = _next(Int, io, model)
Expand All @@ -336,25 +361,25 @@ function _parse_header(io::IO, model::_CacheModel)
nlvci = _next(Int, io, model)
# Number of integer variables in nonlinear objectives
nlvoi = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
# Line 8
# Read the number of nonzeros in Jacobian and gradient, but don't do
# anything with that information.
@assert _next(Int, io, model) >= 0
@assert _next(Int, io, model) >= 0
_read_til_newline(io)
_read_til_newline(io, model)
# Line 9
# We don't support reading variable and constraint names, so just ignore
# them
_read_til_newline(io)
_read_til_newline(io, model)
# Line 10
# We don't support reading common subexpressions
for _ in 1:5
if _next(Int, io, model) > 0
error("Unable to parse NL file : we don't support common exprs")
end
end
_read_til_newline(io)
_read_til_newline(io, model)
# ==========================================================================
# Deal with the integrality of variables. This is quite complicated, so go
# read the README in this folder.
Expand Down Expand Up @@ -387,6 +412,8 @@ function _parse_header(io::IO, model::_CacheModel)
model.variable_type[offset] = types[i]
end
end
# Delay setting is_binary until the end of the header section
model.is_binary = is_binary
return
end

Expand All @@ -412,10 +439,20 @@ end
function _parse_section(io::IO, ::Val{'S'}, model::_CacheModel)
k = _next(Int, io, model)
n = _next(Int, io, model)
suffix = readline(io)
@warn("Skipping suffix: `S$k $n$suffix`")
suffix_name = if model.is_binary
len = _next(Int, io, model)
String(read(io, len))
else
strip(readline(io))
end
@warn("Skipping suffix: `S$k $n $suffix_name`")
# The “4” bit of k indicates whether the suffix is real (that is, double)
# valued or integer valued: (k&4) != 0 --> real valued.
T = ifelse(k & 4 != 0, Float64, Int)
for _ in 1:n
_read_til_newline(io)
_ = _next(Int, io, model)
_ = _next(T, io, model)
_read_til_newline(io, model)
end
return
end
Expand All @@ -440,7 +477,7 @@ end

function _parse_section(io::IO, ::Val{'C'}, model::_CacheModel)
index = _next(Int, io, model) + 1
_read_til_newline(io)
_read_til_newline(io, model)
expr = _force_expr(_parse_expr(io, model))
current = model.constraints[index]
if current == :()
Expand All @@ -460,7 +497,7 @@ function _parse_section(io::IO, ::Val{'O'}, model::_CacheModel)
@assert sense == 0
model.sense = MOI.MIN_SENSE
end
_read_til_newline(io)
_read_til_newline(io, model)
expr = _force_expr(_parse_expr(io, model))
if model.objective == :()
model.objective = expr
Expand All @@ -472,95 +509,99 @@ end

function _parse_section(io::IO, ::Val{'x'}, model::_CacheModel)
index = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
for _ in 1:index
xi = _next(Int, io, model) + 1
v = _next(Float64, io, model)
model.variable_primal[xi] = v
_read_til_newline(io)
_read_til_newline(io, model)
end
return
end

# TODO(odow): we don't read in dual starts.
function _parse_section(io::IO, ::Val{'d'}, model::_CacheModel)
index = _next(Int, io, model)
_read_til_newline(io)
for _ in 1:index
_read_til_newline(io)
n = _next(Int, io, model)
_read_til_newline(io, model)
for _ in 1:n
_ = _next(Int, io, model)
_ = _next(Float64, io, model)
_read_til_newline(io, model)
end
return
end

function _parse_section(io::IO, ::Val{'r'}, model::_CacheModel)
_read_til_newline(io)
_read_til_newline(io, model)
for i in 1:length(model.constraint_lower)
type = _next(Int, io, model)
if type == 0
type = _next(Cchar, io, model)
if type == Cchar('0')
model.constraint_lower[i] = _next(Float64, io, model)
model.constraint_upper[i] = _next(Float64, io, model)
elseif type == 1
elseif type == Cchar('1')
model.constraint_upper[i] = _next(Float64, io, model)
elseif type == 2
elseif type == Cchar('2')
model.constraint_lower[i] = _next(Float64, io, model)
elseif type == 3
elseif type == Cchar('3')
# Free constraint
else
@assert type == 4
@assert type == Cchar('4')
value = _next(Float64, io, model)
model.constraint_lower[i] = value
model.constraint_upper[i] = value
end
_read_til_newline(io)
_read_til_newline(io, model)
end
return
end

function _parse_section(io::IO, ::Val{'b'}, model::_CacheModel)
_read_til_newline(io)
_read_til_newline(io, model)
for i in 1:length(model.variable_lower)
type = _next(Int, io, model)
if type == 0
type = _next(Cchar, io, model)
if type == Cchar('0')
model.variable_lower[i] = _next(Float64, io, model)
model.variable_upper[i] = _next(Float64, io, model)
elseif type == 1
elseif type == Cchar('1')
model.variable_upper[i] = _next(Float64, io, model)
elseif type == 2
elseif type == Cchar('2')
model.variable_lower[i] = _next(Float64, io, model)
elseif type == 3
elseif type == Cchar('3')
# Free variable
else
@assert type == 4
@assert type == Cchar('4')
value = _next(Float64, io, model)
model.variable_lower[i] = value
model.variable_upper[i] = value
end
_read_til_newline(io)
_read_til_newline(io, model)
end
return
end

# We ignore jacobian counts for now
function _parse_section(io::IO, ::Val{'k'}, model::_CacheModel)
_read_til_newline(io)
for _ in 2:length(model.variable_lower)
_read_til_newline(io)
n = _next(Int, io, model)
_read_til_newline(io, model)
for _ in 1:n
_ = _next(Int, io, model)
_read_til_newline(io, model)
end
return
end

function _parse_section(io::IO, ::Val{'J'}, model::_CacheModel)
i = _next(Int, io, model) + 1
nnz = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
expr = Expr(:call, :+)
for _ in 1:nnz
x = _next(Int, io, model)
c = _next(Float64, io, model)
if !iszero(c)
push!(expr.args, Expr(:call, :*, c, MOI.VariableIndex(x + 1)))
end
_read_til_newline(io)
_read_til_newline(io, model)
end
if length(expr.args) == 1
# Linear part is just zeros
Expand All @@ -575,15 +616,15 @@ end
function _parse_section(io::IO, ::Val{'G'}, model::_CacheModel)
i = _next(Int, io, model) + 1
nnz = _next(Int, io, model)
_read_til_newline(io)
_read_til_newline(io, model)
expr = Expr(:call, :+)
for _ in 1:nnz
x = _next(Int, io, model)
c = _next(Float64, io, model)
if !iszero(c)
push!(expr.args, Expr(:call, :*, c, MOI.VariableIndex(x + 1)))
end
_read_til_newline(io)
_read_til_newline(io, model)
end
if length(expr.args) == 1
# Linear part is just zeros
Expand Down
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