// Copyright (c) 2016, 2017 Frank Fischer <frank-fischer@shadow-soft.de>
//
// This program is free software: you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation, either version 3 of the
// License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful, but
// WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>
//
use {DVector, FirstOrderProblem, Minorant, Real, SimpleEvaluation};
use mcf;
use std::fs::File;
use std::io::Read;
use std::f64::INFINITY;
use std::result::Result;
use failure::Error;
/// A solver error.
#[derive(Debug, Fail)]
#[fail(display = "Format error: {}", msg)]
pub struct MCFFormatError {
msg: String,
}
#[derive(Clone, Copy, Debug)]
struct ArcInfo {
arc: usize,
src: usize,
snk: usize,
}
#[derive(Clone, Copy, Debug)]
struct Elem {
ind: usize,
val: Real,
}
pub struct MMCFProblem {
pub multimodel: bool,
nets: Vec<mcf::Solver>,
lhs: Vec<Vec<Vec<Elem>>>,
rhs: DVector,
rhsval: Real,
cbase: Vec<DVector>,
c: Vec<DVector>,
}
impl MMCFProblem {
pub fn read_mnetgen(basename: &str) -> Result<MMCFProblem, Error> {
let mut buffer = String::new();
{
let mut f = try!(File::open(&format!("{}.nod", basename)));
try!(f.read_to_string(&mut buffer));
}
let fnod = buffer
.split_whitespace()
.map(|x| x.parse::<usize>().unwrap())
.collect::<Vec<_>>();
if fnod.len() != 4 {
return Err(MCFFormatError {
msg: format!(
"Expected 4 numbers in {}.nod, but got {}",
basename,
fnod.len()
),
}.into());
}
let ncom = fnod[0];
let nnodes = fnod[1];
let narcs = fnod[2];
let ncaps = fnod[3];
// read nodes
let mut nets = Vec::with_capacity(ncom);
for _ in 0..ncom {
nets.push(try!(mcf::Solver::new(nnodes)))
}
{
let mut f = try!(File::open(&format!("{}.sup", basename)));
buffer.clear();
try!(f.read_to_string(&mut buffer));
}
for line in buffer.lines() {
let mut data = line.split_whitespace();
let node = try!(data.next().unwrap().parse::<usize>());
let com = try!(data.next().unwrap().parse::<usize>());
let supply = try!(data.next().unwrap().parse::<Real>());
try!(nets[com - 1].set_balance(node - 1, supply));
}
// read arcs
let mut arcmap = vec![vec![]; ncom];
let mut cbase = vec![dvec![]; ncom];
// lhs nonzeros
let mut lhsidx = vec![vec![vec![]; ncom]; ncaps];
{
let mut f = try!(File::open(&format!("{}.arc", basename)));
buffer.clear();
try!(f.read_to_string(&mut buffer));
}
for line in buffer.lines() {
let mut data = line.split_whitespace();
let arc = try!(data.next().unwrap().parse::<usize>()) - 1;
let src = try!(data.next().unwrap().parse::<usize>()) - 1;
let snk = try!(data.next().unwrap().parse::<usize>()) - 1;
let com = try!(data.next().unwrap().parse::<usize>()) - 1;
let cost = try!(data.next().unwrap().parse::<Real>());
let cap = try!(data.next().unwrap().parse::<Real>());
let mt = try!(data.next().unwrap().parse::<isize>()) - 1;
assert!(
arc < narcs,
format!(
"Wrong arc number (got: {}, expected in 1..{})",
arc + 1,
narcs
)
);
// set internal coeff
let coeff = arcmap[com].len();
arcmap[com].push(ArcInfo {
arc: arc + 1,
src: src + 1,
snk: snk + 1,
});
// add arc
try!(nets[com].add_arc(src, snk, cost, if cap < 0.0 { INFINITY } else { cap }));
// set objective
cbase[com].push(cost); // + 1e-6 * coeff
// add to mutual capacity constraint
if mt >= 0 {
lhsidx[mt as usize][com].push(coeff);
}
}
// read rhs of coupling constraints
{
let mut f = try!(File::open(&format!("{}.mut", basename)));
buffer.clear();
try!(f.read_to_string(&mut buffer));
}
let mut rhs = dvec![0.0; ncaps];
for line in buffer.lines() {
let mut data = line.split_whitespace();
let mt = try!(data.next().unwrap().parse::<usize>()) - 1;
let cap = try!(data.next().unwrap().parse::<Real>());
rhs[mt] = cap;
}
// set lhs
let mut lhs = vec![vec![vec![]; ncom]; ncaps];
for i in 0..ncaps {
for fidx in 0..ncom {
lhs[i][fidx] = lhsidx[i][fidx]
.iter()
.map(|&j| Elem { ind: j, val: 1.0 })
.collect();
}
}
Ok(MMCFProblem {
multimodel: false,
nets: nets,
lhs: lhs,
rhs: rhs,
rhsval: 0.0,
cbase: cbase,
c: vec![dvec![]; ncom],
})
}
/// Compute costs for a primal solution.
pub fn get_primal_costs(&self, fidx: usize, primals: &[DVector]) -> Real {
if self.multimodel {
primals[0]
.iter()
.enumerate()
.map(|(i, x)| x * self.cbase[fidx][i])
.sum()
} else {
let mut sum = 0.0;
for (fidx, p) in primals.iter().enumerate() {
for (i, x) in p.iter().enumerate() {
sum += x * self.cbase[fidx][i];
}
}
sum
}
}
/// Aggregate primal vectors.
pub fn aggregate_primals_ref(&self, primals: &[(Real, &Vec<DVector>)]) -> Vec<DVector> {
let mut aggr = primals[0]
.1
.iter()
.map(|x| {
let mut r = dvec![];
r.scal(primals[0].0, x);
r
})
.collect::<Vec<_>>();
for &(alpha, primal) in &primals[1..] {
for (j, x) in primal.iter().enumerate() {
aggr[j].add_scaled(alpha, x);
}
}
aggr
}
}
impl<'a> FirstOrderProblem<'a> for MMCFProblem {
type Primal = Vec<DVector>;
type EvalResult = SimpleEvaluation<Vec<DVector>>;
fn num_variables(&self) -> usize {
self.lhs.len()
}
fn lower_bounds(&self) -> Option<Vec<Real>> {
Some(vec![0.0; self.lhs.len()])
}
fn upper_bounds(&self) -> Option<Vec<Real>> {
None
}
fn num_subproblems(&self) -> usize {
if self.multimodel {
self.nets.len()
} else {
1
}
}
#[allow(unused_variables)]
fn evaluate(
&'a mut self,
fidx: usize,
y: &[Real],
nullstep_bound: Real,
relprec: Real,
) -> Result<Self::EvalResult, Error> {
// compute costs
self.rhsval = 0.0;
for i in 0..self.c.len() {
self.c[i].clear();
self.c[i].extend(self.cbase[i].iter());
}
for (i, &y) in y.iter().enumerate().filter(|&(i, &y)| y != 0.0) {
self.rhsval += self.rhs[i] * y;
for (fidx, c) in self.c.iter_mut().enumerate() {
for elem in &self.lhs[i][fidx] {
c[elem.ind] += y * elem.val;
}
}
}
debug!("y={:?}", y);
for i in 0..self.nets.len() {
debug!("c[{}]={}", i, self.c[i]);
try!(self.nets[i].set_objective(&self.c[i]));
}
// solve subproblems
for (i, net) in self.nets.iter_mut().enumerate() {
try!(net.solve());
debug!("c[{}]={}", i, try!(net.objective()));
}
// compute minorant
if self.multimodel {
let objective;
let mut subg;
if fidx == 0 {
subg = self.rhs.clone();
objective = self.rhsval - try!(self.nets[fidx].objective());
} else {
subg = dvec![0.0; self.rhs.len()];
objective = -try!(self.nets[fidx].objective());
}
let sol = try!(self.nets[fidx].get_solution());
for (i, lhs) in self.lhs.iter().enumerate() {
subg[i] -= lhs[fidx]
.iter()
.map(|elem| elem.val * sol[elem.ind])
.sum::<Real>();
}
Ok(SimpleEvaluation {
objective: objective,
minorants: vec![
(
Minorant {
constant: objective,
linear: subg,
},
vec![sol],
),
],
})
} else {
let mut objective = self.rhsval;
let mut sols = Vec::with_capacity(self.nets.len());
for i in 0..self.nets.len() {
objective -= try!(self.nets[i].objective());
sols.push(try!(self.nets[i].get_solution()));
}
let mut subg = self.rhs.clone();
for (i, lhs) in self.lhs.iter().enumerate() {
for (fidx, flhs) in lhs.iter().enumerate() {
subg[i] -= flhs.iter()
.map(|elem| elem.val * sols[fidx][elem.ind])
.sum::<Real>();
}
}
Ok(SimpleEvaluation {
objective: objective,
minorants: vec![
(
Minorant {
constant: objective,
linear: subg,
},
sols,
),
],
})
}
}
fn aggregate_primals(&mut self, primals: Vec<(Real, Vec<DVector>)>) -> Vec<DVector> {
self.aggregate_primals_ref(&primals
.iter()
.map(|&(alpha, ref x)| (alpha, x))
.collect::<Vec<_>>())
}
}