Exemple #1
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// SmpDirectorDeriv1 computes the first order derivative of the SMP director
//  Notes: Only non-zero components are returned; i.e. dNdL[i] := dNdL[i][i]
func SmpDirectorDeriv1(dNdL []float64, L []float64, a, b, β, ϵ float64) {
	if SMPUSESRAMP {
		dNdL[0] = -b * fun.SrampD1(a*L[0], β) * math.Pow(ϵ+fun.Sramp(a*L[0], β), -b-1.0)
		dNdL[1] = -b * fun.SrampD1(a*L[1], β) * math.Pow(ϵ+fun.Sramp(a*L[1], β), -b-1.0)
		dNdL[2] = -b * fun.SrampD1(a*L[2], β) * math.Pow(ϵ+fun.Sramp(a*L[2], β), -b-1.0)
	} else {
		eps := β
		dNdL[0] = -b * fun.SabsD1(a*L[0], eps) * math.Pow(ϵ+fun.Sabs(a*L[0], eps), -b-1.0)
		dNdL[1] = -b * fun.SabsD1(a*L[1], eps) * math.Pow(ϵ+fun.Sabs(a*L[1], eps), -b-1.0)
		dNdL[2] = -b * fun.SabsD1(a*L[2], eps) * math.Pow(ϵ+fun.Sabs(a*L[2], eps), -b-1.0)
	}
}
Exemple #2
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// SmpDirectorDeriv2 computes the second order derivative of the SMP director
//  Notes: Only the non-zero components are returned; i.e.: d²NdL2[i] := d²N[i]/dL[i]dL[i]
func SmpDirectorDeriv2(d2NdL2 []float64, L []float64, a, b, β, ϵ float64) {
	var F_i, G_i, H_i float64
	for i := 0; i < 3; i++ {
		if SMPUSESRAMP {
			F_i = fun.Sramp(a*L[i], β)
			G_i = fun.SrampD1(a*L[i], β)
			H_i = fun.SrampD2(a*L[i], β)
		} else {
			eps := β
			F_i = fun.Sabs(a*L[i], eps)
			G_i = fun.SabsD1(a*L[i], eps)
			H_i = fun.SabsD2(a*L[i], eps)
		}
		d2NdL2[i] = a * b * ((b+1.0)*G_i*G_i - (ϵ+F_i)*H_i) * math.Pow(ϵ+F_i, -b-2.0)
	}
}
Exemple #3
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// rampderiv returns the ramp function first derivative
func (o *ElemP) rampD1(x float64) float64 {
	if o.Macaulay {
		return fun.Heav(x)
	}
	return fun.SrampD1(x, o.βrmp)
}