// creates an AtMost constraint
// with coefficients in weights,
// variables x1..xm
func CreatePBOffset(offset int, weights []int64, K int64) (pb Threshold) {
pb.Entries = make([]Entry, len(weights))
pb.Typ = LE
pb.K = K
// p := sat.Pred("x")
for i := 0; i < len(weights); i++ {
//l := sat.Literal{true, sat.NewAtomP(sat.Pred("x_{" + strconv.Itoa(i+offset) + "}"))}
l := sat.Literal{true, sat.NewAtomP(sat.Pred("x" + strconv.Itoa(i+offset) + "}"))}
pb.Entries[i] = Entry{l, weights[i]}
}
return
}
// returns list of *pb; first one is optimization statement, possibly empty
func parse(filename string) (pbs []*constraints.Threshold, err error) {
input, err2 := os.Open(filename)
defer input.Close()
if err2 != nil {
err = errors.New("Please specify correct path to instance. Does not exist")
return
}
scanner := bufio.NewScanner(input)
buf := make([]byte, 0, 64*1024)
scanner.Buffer(buf, 1024*1024)
// 0 : first line, 1 : rest of the lines
var count int
state := 1
t := 0
pbs = make([]*constraints.Threshold, 0)
for scanner.Scan() {
l := strings.Trim(scanner.Text(), " ")
if l == "" || strings.HasPrefix(l, "%") || strings.HasPrefix(l, "*") {
continue
}
elements := strings.Fields(l)
if len(elements) == 1 { // quick hack to ignore single element lines (not necessary)
continue
}
switch state {
case 0: // deprecated: for parsing the "header" of pb files, now parser is flexible
{
glob.D(l)
var b1 error
count, b1 = strconv.Atoi(elements[4])
vars, b2 := strconv.Atoi(elements[2])
if b1 != nil || b2 != nil {
glob.D("cant convert to threshold:", l)
panic("bad conversion of numbers")
}
glob.D("File PB file with", count, "constraints and", vars, "variables")
state = 1
}
case 1:
{
var n int // number of entries
var f int // index of entry
var o bool //optimization
var pb constraints.Threshold
offset_back := 0
if elements[len(elements)-1] != ";" {
offset_back = 1
}
if elements[0] == "min:" || elements[0] == "Min" {
o = true
n = (len(elements) + offset_back - 2) / 2
f = 1
} else {
o = false
n = (len(elements) + offset_back - 3) / 2
f = 0
}
pb.Entries = make([]constraints.Entry, n)
for i := f; i < 2*n; i++ {
weight, b1 := strconv.ParseInt(elements[i], 10, 64)
i++
if b1 != nil {
glob.D("cant convert to threshold:", elements[i], "\nin PB\n", l)
panic("bad conversion of numbers")
}
atom := sat.NewAtomP(sat.Pred(elements[i]))
pb.Entries[(i-f)/2] = constraints.Entry{sat.Literal{true, atom}, weight}
}
// fake empty opt in case it does not exist
if t == 0 && !o {
pbs = append(pbs, &constraints.Threshold{})
t++
}
pb.Id = t
if o {
pb.Typ = constraints.OPT
glob.D("Scanned optimization statement")
} else {
pb.K, err = strconv.ParseInt(elements[len(elements)-2+offset_back], 10, 64)
if err != nil {
glob.A(false, " cant parse threshold, error", err.Error(), pb.K)
}
typS := elements[len(elements)-3+offset_back]
if typS == ">=" {
pb.Typ = constraints.GE
} else if typS == "<=" {
pb.Typ = constraints.LE
} else if typS == "==" || typS == "=" {
pb.Typ = constraints.EQ
} else {
glob.A(false, "cant convert to threshold, equationtype typS:", typS)
}
}
pbs = append(pbs, &pb)
t++
//fmt.Println(pb.Id)
//pb.Print10()
}
}
}
glob.A(len(pbs) == t, "Id of constraint must correspond to position")
glob.D("Scanned", t-1, "PB constraints.")
if len(pbs) > 0 && !pbs[0].Empty() {
glob.D("Scanned OPT statement.")
}
return
}