// Extrapolator computes the extrapolation matrix for this Shape with a combination of integration points 'ips'
// Note: E[nverts][nip] must be pre-allocated
func (o *Shape) Extrapolator(E [][]float64, ips []*Ipoint) (err error) {
la.MatFill(E, 0)
nip := len(ips)
N := o.GetShapeMatAtIps(ips)
if nip < o.Nverts {
ξ := o.GetNodesNatCoordsMat()
ξh := o.GetIpsNatCoordsMat(ips)
ξhi := la.MatAlloc(o.Gndim+1, nip)
Ni := la.MatAlloc(o.Nverts, nip)
err = la.MatInvG(Ni, N, 1e-10)
if err != nil {
return
}
err = la.MatInvG(ξhi, ξh, 1e-10)
if err != nil {
return
}
ξhξhI := la.MatAlloc(nip, nip) // ξh * inv(ξh)
for k := 0; k < o.Gndim+1; k++ {
for j := 0; j < nip; j++ {
for i := 0; i < nip; i++ {
ξhξhI[i][j] += ξh[i][k] * ξhi[k][j]
}
for i := 0; i < o.Nverts; i++ {
E[i][j] += ξ[i][k] * ξhi[k][j] // ξ * inv(ξh)
}
}
}
for i := 0; i < o.Nverts; i++ {
for j := 0; j < nip; j++ {
for k := 0; k < nip; k++ {
I_kj := 0.0
if j == k {
I_kj = 1.0
}
E[i][j] += Ni[i][k] * (I_kj - ξhξhI[k][j])
}
}
}
} else {
err = la.MatInvG(E, N, 1e-10)
if err != nil {
return
}
}
return
}
// CalcD computes algorithmic tangent operator
func (o *PrincStrainsUp) CalcD(D [][]float64, s *State) (err error) {
// elastic response
if !s.Loading {
o.Mdl.ElastD(D, s)
return
}
// eigenvalues/projectors of trial elastic strain
err = tsr.M_EigenValsProjsNum(o.P, o.Lεetr, s.EpsTr)
if err != nil {
return
}
// derivatives of eigenprojectors w.r.t trial elastic strains
err = tsr.M_EigenProjsDerivAuto(o.dPdT, s.EpsTr, o.Lεetr, o.P)
if err != nil {
io.Pforan("EpsTr = %v\n", s.EpsTr)
io.Pforan("Lεetr = %v\n", o.Lεetr)
la.PrintMat("P", o.P, "%10g", false)
return
}
// eigenvalues of strains
err = tsr.M_EigenValsNum(o.Lεe, s.EpsE)
if err != nil {
return
}
// compute Lσ, De and Jacobian
o.Mdl.E_CalcSig(o.Lσ, o.Lεe)
err = o.Mdl.L_SecondDerivs(o.N, o.Nb, o.A, o.h, o.Mb, o.a, o.b, o.c, o.Lσ, s.Alp)
if err != nil {
return err
}
o.Mdl.E_CalcDe(o.De, o.Lεe)
o.calcJafterDerivs(o.J, o.Lεe, s.Alp, s.Dgam)
// invert Jacobian => Ji
err = la.MatInvG(o.Ji, o.J, 1e-10)
if err != nil {
return
}
// compute De and Dt = De * Ji
for i := 0; i < 3; i++ {
for j := 0; j < 3; j++ {
o.Dt[i][j] = 0
for k := 0; k < 3; k++ {
o.Dt[i][j] += o.De[i][k] * o.Ji[k][j]
}
}
}
// compute D
for i := 0; i < o.Nsig; i++ {
for j := 0; j < o.Nsig; j++ {
D[i][j] = 0.0
for k := 0; k < 3; k++ {
for l := 0; l < 3; l++ {
D[i][j] += o.Dt[k][l] * o.P[k][i] * o.P[l][j]
}
D[i][j] += o.Lσ[k] * o.dPdT[k][i][j]
}
}
}
return
}
// Solve solves non-linear problem f(x) == 0
func (o *NlSolver) Solve(x []float64, silent bool) (err error) {
// compute scaling vector
la.VecScaleAbs(o.scal, o.atol, o.rtol, x) // scal := Atol + Rtol*abs(x)
// evaluate function @ x
err = o.Ffcn(o.fx, x) // fx := f(x)
o.NFeval, o.NJeval = 1, 0
if err != nil {
return
}
// show message
if !silent {
o.msg("", 0, 0, 0, true, false)
}
// iterations
var Ldx, Ldx_prev, Θ float64 // RMS norm of delta x, convergence rate
var fx_max float64
var nfv int
for o.It = 0; o.It < o.MaxIt; o.It++ {
// check convergence on f(x)
fx_max = la.VecLargest(o.fx, 1.0) // den = 1.0
if fx_max < o.ftol {
if !silent {
o.msg("fx_max(ini)", o.It, Ldx, fx_max, false, true)
}
break
}
// show message
if !silent {
o.msg("", o.It, Ldx, fx_max, false, false)
}
// output
if o.Out != nil {
o.Out(x)
}
// evaluate Jacobian @ x
if o.It == 0 || !o.CteJac {
if o.useDn {
err = o.JfcnDn(o.J, x)
} else {
if o.numJ {
err = Jacobian(&o.Jtri, o.Ffcn, x, o.fx, o.w, false)
o.NFeval += o.neq
} else {
err = o.JfcnSp(&o.Jtri, x)
}
}
o.NJeval += 1
if err != nil {
return
}
}
// dense solution
if o.useDn {
// invert matrix
err = la.MatInvG(o.Ji, o.J, 1e-10)
if err != nil {
return chk.Err(_nls_err1, err.Error())
}
// solve linear system (compute mdx) and compute lin-search data
o.φ = 0.0
for i := 0; i < o.neq; i++ {
o.mdx[i], o.dφdx[i] = 0.0, 0.0
for j := 0; j < o.neq; j++ {
o.mdx[i] += o.Ji[i][j] * o.fx[j] // mdx = inv(J) * fx
o.dφdx[i] += o.J[j][i] * o.fx[j] // dφdx = tra(J) * fx
}
o.φ += o.fx[i] * o.fx[i]
}
o.φ *= 0.5
// sparse solution
} else {
// init sparse solver
if o.It == 0 {
symmetric, verbose, timing := false, false, false
err := o.lis.InitR(&o.Jtri, symmetric, verbose, timing)
if err != nil {
return chk.Err(_nls_err9, err.Error())
}
}
// factorisation (must be done for all iterations)
o.lis.Fact()
// solve linear system => compute mdx
o.lis.SolveR(o.mdx, o.fx, false) // mdx = inv(J) * fx false => !sumToRoot
// compute lin-search data
if o.Lsearch {
o.φ = 0.5 * la.VecDot(o.fx, o.fx)
la.SpTriMatTrVecMul(o.dφdx, &o.Jtri, o.fx) // dφdx := transpose(J) * fx
}
}
//io.Pforan("φ = %v\n", o.φ)
//io.Pforan("dφdx = %v\n", o.dφdx)
// update x
Ldx = 0.0
for i := 0; i < o.neq; i++ {
o.x0[i] = x[i]
x[i] -= o.mdx[i]
Ldx += (o.mdx[i] / o.scal[i]) * (o.mdx[i] / o.scal[i])
}
Ldx = math.Sqrt(Ldx / float64(o.neq))
// calculate fx := f(x) @ update x
err = o.Ffcn(o.fx, x)
o.NFeval += 1
if err != nil {
return
}
// check convergence on f(x) => avoid line-search if converged already
fx_max = la.VecLargest(o.fx, 1.0) // den = 1.0
if fx_max < o.ftol {
if !silent {
o.msg("fx_max", o.It, Ldx, fx_max, false, true)
}
break
}
// check convergence on Ldx
if Ldx < o.fnewt {
if !silent {
o.msg("Ldx", o.It, Ldx, fx_max, false, true)
}
break
}
// call line-search => update x and fx
if o.Lsearch {
nfv, err = LineSearch(x, o.fx, o.Ffcn, o.mdx, o.x0, o.dφdx, o.φ, o.LsMaxIt, true)
o.NFeval += nfv
if err != nil {
return chk.Err(_nls_err2, err.Error())
}
Ldx = 0.0
for i := 0; i < o.neq; i++ {
Ldx += ((x[i] - o.x0[i]) / o.scal[i]) * ((x[i] - o.x0[i]) / o.scal[i])
}
Ldx = math.Sqrt(Ldx / float64(o.neq))
fx_max = la.VecLargest(o.fx, 1.0) // den = 1.0
if Ldx < o.fnewt {
if !silent {
o.msg("Ldx(linsrch)", o.It, Ldx, fx_max, false, true)
}
break
}
}
// check convergence rate
if o.It > 0 && o.ChkConv {
Θ = Ldx / Ldx_prev
if Θ > 0.99 {
return chk.Err(_nls_err3, Θ, Ldx, Ldx_prev)
}
}
Ldx_prev = Ldx
}
// output
if o.Out != nil {
o.Out(x)
}
// check convergence
if o.It == o.MaxIt {
err = chk.Err(_nls_err4, o.It)
}
return
}
