// Krefine returns a new Nurbs with knots refined
// Note: X[gnd][numNewKnots]
func (o *Nurbs) Krefine(X [][]float64) (O *Nurbs) {
// check
if len(X) != o.gnd {
chk.Panic("size of new knots array X must be [gnd==%d][numNewKnots]. len==%d of first dimension is incorrect", o.gnd, len(X))
}
// number of new knots and first and last knots
nk, a, b := make([]int, 3), make([]int, 3), make([]int, 3)
for d := 0; d < o.gnd; d++ {
nk[d] = len(X[d])
a[d] = o.b[d].find_span(X[d][0])
b[d] = o.b[d].find_span(X[d][nk[d]-1])
}
// new knots array
Unew := make([][]float64, o.gnd)
Unew[0] = make([]float64, o.b[0].m+nk[0])
if o.gnd > 1 {
Unew[1] = make([]float64, o.b[1].m+nk[1])
}
if o.gnd > 2 {
Unew[2] = make([]float64, o.b[2].m+nk[2])
}
// refine
var Qnew [][][][]float64
switch o.gnd {
case 1:
Qnew = utl.Deep4alloc(o.n[0]+nk[0], o.n[1], o.n[2], 4)
krefine(Unew, Qnew, o.Q, 0, X[0], o.b[0].T, o.n, o.p, a[0], b[0])
case 2:
// along 0
Qtmp := utl.Deep4alloc(o.n[0]+nk[0], o.n[1], o.n[2], 4)
krefine(Unew, Qtmp, o.Q, 0, X[0], o.b[0].T, o.n, o.p, a[0], b[0])
// along 1
nn := make([]int, 3)
copy(nn, o.n)
nn[0] += nk[0]
Qnew = utl.Deep4alloc(nn[0], o.n[1]+nk[1], o.n[2], 4)
krefine(Unew, Qnew, Qtmp, 1, X[1], o.b[1].T, nn, o.p, a[1], b[1])
case 3:
chk.Panic("nurbs.go: Krefine: gnd=3 not implemented yet")
}
// initialize new nurbs
O = new(Nurbs)
O.Init(o.gnd, o.p, Unew)
O.Q = Qnew
return
}
// CloneCtrlsAlongCurve returns a copy of control points @ 2D boundary
func (o *Nurbs) CloneCtrlsAlongCurve(iAlong, jAt int) (Qnew [][][][]float64) {
Qnew = utl.Deep4alloc(o.n[iAlong], 1, 1, 4)
var i, j int
for m := 0; m < o.n[iAlong]; m++ {
i, j = m, jAt
if iAlong == 1 {
i, j = jAt, m
}
for e := 0; e < 4; e++ {
Qnew[m][0][0][e] = o.Q[i][j][0][e]
}
}
return
}
// Init initialises Nurbs
func (o *Nurbs) Init(gnd int, ords []int, knots [][]float64) {
// essential
o.gnd = gnd
o.p = make([]int, 3)
// B-splines
o.b = make([]Bspline, o.gnd)
o.n = make([]int, 3)
for d := 0; d < o.gnd; d++ {
o.p[d] = ords[d]
o.b[d].Init(knots[d], o.p[d])
o.n[d] = o.b[d].NumBasis()
if o.n[d] < 2 {
chk.Panic("number of knots is incorrect for dimension %d. n == %d is invalid", d, o.n[d])
}
}
for d := o.gnd; d < 3; d++ {
o.n[d] = 1
}
// ids of control points
nctrl := o.n[0] * o.n[1] * o.n[2]
o.l2i = make([][]int, nctrl)
for l := 0; l < nctrl; l++ {
o.l2i[l] = make([]int, 3)
switch o.gnd {
case 1:
o.l2i[l][0] = l
case 2:
o.l2i[l][0] = l % o.n[0] // i
o.l2i[l][1] = l / o.n[0] // j
case 3:
c := l % (o.n[0] * o.n[1])
o.l2i[l][0] = c % o.n[0] // i
o.l2i[l][1] = c / o.n[0] // j
o.l2i[l][2] = l / (o.n[0] * o.n[1]) // k
}
}
// auxiliary
o.span = make([]int, 3)
o.idx = make([]int, 3)
o.cw = make([]float64, 4)
o.rr = utl.Deep3alloc(o.p[0]+1, o.p[1]+1, o.p[2]+1)
o.drr = utl.Deep4alloc(o.p[0]+1, o.p[1]+1, o.p[2]+1, o.gnd)
o.dww = make([]float64, o.gnd)
}
// CloneCtrlsAlongSurface returns a copy of control points @ 3D boundary
func (o *Nurbs) CloneCtrlsAlongSurface(iAlong, jAlong, kAt int) (Qnew [][][][]float64) {
Qnew = utl.Deep4alloc(o.n[iAlong], o.n[jAlong], 1, 4)
var i, j, k int
for m := 0; m < o.n[iAlong]; m++ {
for n := 0; n < o.n[jAlong]; n++ {
switch {
case iAlong == 0 && jAlong == 1:
i, j, k = m, n, kAt
case iAlong == 1 && jAlong == 2:
i, j, k = kAt, m, n
case iAlong == 2 && jAlong == 0:
i, j, k = n, kAt, m
default:
chk.Panic("clone Q surface is specified by 'along' indices in (0,1) or (1,2) or (2,0). (%d,%d) is incorrect", iAlong, jAlong)
}
for e := 0; e < 4; e++ {
Qnew[m][n][0][e] = o.Q[i][j][k][e]
}
}
}
return
}
// SetControl sets control points from list of global vertices
func (o *Nurbs) SetControl(verts [][]float64, ctrls []int) {
// check
nctrl := o.n[0] * o.n[1] * o.n[2]
if nctrl != len(ctrls) {
chk.Panic("number of control points must be equal to %d. nctrl == %d is incorrect", nctrl, len(ctrls))
}
// set control points
o.Q = utl.Deep4alloc(o.n[0], o.n[1], o.n[2], 4)
for i := 0; i < o.n[0]; i++ {
for j := 0; j < o.n[1]; j++ {
for k := 0; k < o.n[2]; k++ {
l := i + j*o.n[0] + k*o.n[0]*o.n[1]
g := ctrls[l]
for e := 0; e < 3; e++ {
o.Q[i][j][k][e] = verts[g][e] * verts[g][3]
}
o.Q[i][j][k][3] = verts[g][3]
}
}
}
}