// Init initialises Munkres' structure
func (o *Munkres) Init(nrow, ncol int) {
chk.IntAssertLessThan(0, nrow) // nrow > 1
chk.IntAssertLessThan(0, ncol) // ncol > 1
o.nrow, o.ncol = nrow, ncol
o.C = utl.DblsAlloc(o.nrow, o.ncol)
o.M = make([][]Mask_t, o.nrow)
for i := 0; i < o.nrow; i++ {
o.M[i] = make([]Mask_t, o.ncol)
}
o.Links = make([]int, o.nrow)
npath := 2*o.nrow + 1 // TODO: check this
o.path = utl.IntsAlloc(npath, 2)
o.row_covered = make([]bool, o.nrow)
o.col_covered = make([]bool, o.ncol)
}
// CxIntOrd performs the crossover in a pair of individuals with integer numbers
// that correspond to a ordered sequence, e.g. for traveling salesman problem
// Output:
// a and b -- offspring chromosomes
// Note: using OX1 method explained in [1] (proposed in [2])
// References:
// [1] Larrañaga P, Kuijpers CMH, Murga RH, Inza I and Dizdarevic S. Genetic Algorithms for the
// Travelling Salesman Problem: A Review of Representations and Operators. Artificial
// Intelligence Review, 13:129-170; 1999. doi:10.1023/A:1006529012972
// [2] Davis L. Applying Adaptive Algorithms to Epistatic Domains. Proceedings of International
// Joint Conference on Artificial Intelligence, 162-164; 1985.
// Example:
// data:
// 0 1 2 3 4 5 6 7
// A = a b | c d e | f g h size = 8
// B = b d | f h g | e c a cuts = [2, 5]
// ↑ ↑ ↑ ends = [2, 5, 8]
// 2 5 8
// first step: copy subtours
// a = . . | f h g | . . .
// b = . . | c d e | . . .
// second step: copy unique from subtour's end, position 5
// start adding here
// ↓ 5 6 7 0 1 2 3 4
// a = d e | f h g | a b c get from A: | f̶ g̶ h̶ | a b | c d e
// b = h g | c d e | a b f get from B: | e̶ c̶ a | b d̶ | f h g
func CxIntOrd(a, b, A, B []int, prms *Parameters) {
size := len(A)
if !rnd.FlipCoin(prms.IntPc) || size < 3 {
for i := 0; i < len(A); i++ {
a[i], b[i] = A[i], B[i]
}
return
}
var s, t int
var cuts []int
if len(cuts) == 2 {
s, t = cuts[0], cuts[1]
} else {
s = rnd.Int(1, size-2)
t = rnd.Int(s+1, size-1)
}
chk.IntAssertLessThan(s, t)
acore := B[s:t]
bcore := A[s:t]
ncore := t - s
acorehas := make(map[int]bool) // TODO: check if map can be replaced => improve efficiency
bcorehas := make(map[int]bool)
for i := 0; i < ncore; i++ {
a[s+i] = acore[i]
b[s+i] = bcore[i]
acorehas[acore[i]] = true
bcorehas[bcore[i]] = true
}
ja, jb := t, t
for i := 0; i < size; i++ {
k := (i + t) % size
if !acorehas[A[k]] {
a[ja] = A[k]
ja++
if ja == size {
ja = 0
}
}
if !bcorehas[B[k]] {
b[jb] = B[k]
jb++
if jb == size {
jb = 0
}
}
}
return
}
func (o *SimpleFltProb) find_best() (x, f, g, h []float64) {
chk.IntAssertLessThan(0, o.Nfeasible) // 0 < nfeasible
nx := len(o.C.RangeFlt)
x = make([]float64, nx)
f = make([]float64, o.nf)
g = make([]float64, o.ng)
h = make([]float64, o.nh)
copy(x, o.Xbest[0])
o.Fcn(f, g, h, x)
for i := 1; i < o.Nfeasible; i++ {
o.Fcn(o.ff[0], o.gg[0], o.hh[0], o.Xbest[i])
_, other_dom := utl.DblsParetoMin(f, o.ff[0])
if other_dom {
copy(x, o.Xbest[i])
copy(f, o.ff[0])
copy(g, o.gg[0])
copy(h, o.hh[0])
}
}
return
}
// Set sets a constraint if it does NOT exist yet.
// key -- can be Dof key such as "ux", "uy" or constraint type such as "mpc" or "rigid"
// extra -- is a keycode-style data. e.g. "!type:incsup2d !alp:30"
// Notes: 1) the default for key is single point constraint; e.g. "ux", "uy", ...
// 2) hydraulic head can be set with key == "H"
func (o *EssentialBcs) Set(key string, nodes []*Node, fcn fun.Func, extra string) (err error) {
// len(nod) must be greater than 0
chk.IntAssertLessThan(0, len(nodes)) // 0 < len(nod)
// skip nil node
if nodes[0] == nil {
return
}
// space dimension
ndim := len(nodes[0].Vert.C)
// rigid element
if key == "rigid" {
a := nodes[0].Dofs
for i := 1; i < len(nodes); i++ {
for j, b := range nodes[i].Dofs {
o.add(key, []int{a[j].Eq, b.Eq}, []float64{1, -1}, &fun.Zero)
}
}
return // success
}
// inclined support
if key == "incsup" {
// check
if ndim != 2 {
return chk.Err("inclined support works only in 2D for now")
}
// get data
var α float64
if val, found := io.Keycode(extra, "alp"); found {
α = io.Atof(val) * math.Pi / 180.0
}
co, si := math.Cos(α), math.Sin(α)
// set for all nodes
for _, nod := range nodes {
// find existent constraints and deactivate them
eqx := nod.Dofs[0].Eq
eqy := nod.Dofs[1].Eq
for _, eq := range []int{eqx, eqy} {
for _, idx := range o.Eq2idx[eq] {
pair := o.BcsTmp[idx]
if pair.bc.Key != "rigid" {
pair.bc.Inact = true
}
}
}
// set constraint
o.add(key, []int{eqx, eqy}, []float64{co, si}, &fun.Zero)
}
return // success
}
// hydraulic head
if key == "hst" {
// set for all nodes
for _, nod := range nodes {
// create function
// Note: fcn is a shift such that pl = pl(z) - shift(t)
d := nod.GetDof("pl")
if d == nil {
continue // node doesn't have key. ex: pl in qua8/qua4 elements
}
z := nod.Vert.C[1] // 2D
if ndim == 3 {
z = nod.Vert.C[2] // 3D
}
plVal, _, err := o.HydFcn.Calc(z)
if err != nil {
return chk.Err("cannot set hst (hydrostatic) essential boundary condition")
}
pl := fun.Add{
B: 1, Fb: &fun.Cte{C: plVal},
A: -1, Fa: fcn,
}
// set constraint
o.add_single("pl", d.Eq, &pl)
}
return // success
}
// single-point constraint
for _, nod := range nodes {
d := nod.GetDof(key)
if d == nil {
return // success
}
o.add_single(key, d.Eq, fcn)
}
// success
return
}
