fix some degree=0 cases

Project.toml

@@ -1,7 +1,7 @@
 name = "NURBS"
 uuid = "dde13934-061e-461b-aa91-2c0fad390a0d"
 authors = ["Bernd Hofmann <[email protected]> and contributors"]
-version = "0.6.0"
+version = "0.6.1"
 
 [deps]
 LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"

src/fundamentalOperations/knotInsertion.jl

@@ -232,7 +232,7 @@ function extendKnotVector!(knotVecOrig, degree::Int, newParametricPoint::Real, m
 
  # --- check whether resulting mulitplicity makes sense
  newMult = multiplicity + oldMult
- if newMult > degree
+ if newMult > degree + 1
  @info "The multiplicity of the inserted knot is limited to $(degree)."
  newMult = degree
  end
@@ -258,13 +258,14 @@ function extendControlPoints!(
  controlPoints, knotVecOrig, degree::Int, pos::Int, uNew::Real, multiplicity::Int, oldMult::Int, weights=[]
 )
 
- T = eltype(controlPoints[1])
+ degree == 0 && return extendControlPoints!(controlPoints, pos, multiplicity, oldMult) # not so nice - why does algorithm not hold for degree=0?
+ #T = eltype(controlPoints[1])
 
  # --- computation including weights
  if !isempty(weights)
 
- newControlPoints = [SVector{3,T}(0.0, 0.0, 0.0) for i in 1:(degree - oldMult + multiplicity - 1)]
- newWeights = [T(0.0) for i in 1:(degree - oldMult + multiplicity - 1)]
+ newControlPoints = similar(controlPoints, degree - oldMult + multiplicity - 1) #[SVector{3,T}(0.0, 0.0, 0.0) for i in 1:(degree - oldMult + multiplicity - 1)]
+ newWeights = similar(weights, degree - oldMult + multiplicity - 1) #[T(0.0) for i in 1:(degree - oldMult + multiplicity - 1)]
 
  auxC = controlPoints[(pos - degree):(pos - oldMult)]
  auxW = weights[(pos - degree):(pos - oldMult)]
@@ -301,7 +302,7 @@ function extendControlPoints!(
  end
 
  # --- computation when there are no weights
- newControlPoints = [SVector{3,T}(0.0, 0.0, 0.0) for i in 1:(degree - oldMult + multiplicity - 1)]
+ newControlPoints = similar(controlPoints, degree - oldMult + multiplicity - 1) #[SVector{3,T}(0.0, 0.0, 0.0) for i in 1:(degree - oldMult + multiplicity - 1)]
 
  aux = controlPoints[(pos - degree):(pos - oldMult)]
  for r in 1:multiplicity
@@ -312,7 +313,6 @@ function extendControlPoints!(
  αᵢ = (uNew - knotVecOrig[L]) / (knotVecOrig[pos + i] - knotVecOrig[L])
  aux[i] = αᵢ * aux[i + 1] + (1.0 - αᵢ) * aux[i]
  end
-
  newControlPoints[r] = aux[1]
  newControlPoints[end - r + 1] = aux[end - r]
  end
@@ -327,3 +327,23 @@ function extendControlPoints!(
 
  return nothing
 end
+
+"""
+Lowest order polynomial degree = 0.
+
+Can multiplicity be maximum 1 and/or oldMult maximum 0? => simplify below algorithm further.
+"""
+function extendControlPoints!(controlPoints, pos::Int, multiplicity::Int, oldMult::Int)
+
+ newControlPoints = similar(controlPoints, oldMult + multiplicity)
+
+ aux = controlPoints[(pos):(pos - oldMult)]
+ for r in 1:multiplicity
+ newControlPoints[r] = aux[1]
+ end
+
+ # splice new computed points into array (replacing the correct amount)
+ splice!(controlPoints, (pos + 1):(pos - oldMult - 1), newControlPoints)
+
+ return nothing
+end

src/utils.jl

@@ -226,6 +226,8 @@ Return the Greville sites (as defined in [3]) corresponding to the given knotvec
 """
 function greville(kVec, degree::Int)
 
+ degree == 0 && return unique(kVec)
+
  N = length(kVec) - degree - 1 # number of B-splines
  gSites = zeros(eltype(kVec), N)