added: ASMsxDLag::findElement

this finds the element of a parameter value
and optionally calculates the local coordinates
of an integration point.

src/ASM/ASMs2DLag.C

@@ -773,3 +773,21 @@ bool ASMs2DLag::write(std::ostream& os, int) const
 {
   return this->writeLagBasis(os, "quad");
 }
+
+
+int ASMs2DLag::findElement(double u, double v,
+                           double* xi, double* eta) const
+{
+  double du = 1.0 / (nx-1);
+  double dv = 1.0 / (ny-1);
+
+  int elmx = std::min(nx-2.0, floor(u / du));
+  int elmy = std::min(ny-2.0, floor(v / dv));
+
+  if (xi)
+    *xi   = -1.0 + (u - elmx*du)*2.0 / du;
+  if (eta)
+    *eta  = -1.0 + (v - elmy*dv)*2.0 / dv;
+
+  return 1 + elmx + elmy*(nx-1);
+}

src/ASM/ASMs2DLag.h

@@ -81,6 +81,10 @@ protected:
   //! \param[in] Xnod Coordinates of the node
   void setCoord(size_t inod, const Vec3& Xnod);
 
+  //! \brief Find element for parameter, and optionally calculate local coordinates.
+  int findElement(double u, double v,
+                  double* xi = nullptr, double* eta = nullptr) const;
+
 public:
   //! \brief Updates the nodal coordinates for this patch.
   //! \param[in] displ Incremental displacements to update the coordinates with

src/ASM/ASMs3DLag.C

@@ -954,6 +954,28 @@ bool ASMs3DLag::evalSolution (Matrix& sField, const Vector& locSol,
 }
 
 
+int ASMs3DLag::findElement(double u, double v, double w,
+                           double* xi, double* eta, double* zeta) const
+{
+  double du = 1.0 / (nx-1);
+  double dv = 1.0 / (ny-1);
+  double dw = 1.0 / (nz-1);
+
+  int elmx = std::min(nx-2.0, floor(u / du));
+  int elmy = std::min(ny-2.0, floor(v / dv));
+  int elmz = std::min(nz-2.0, floor(w / dw));
+
+  if (xi)
+    *xi   = -1.0 + (u - elmx*du)*2.0 / du;
+  if (eta)
+    *eta  = -1.0 + (v - elmy*dv)*2.0 / dv;
+  if (zeta)
+    *zeta = -1.0 + (w - elmz*dw)*2.0 / dw;
+
+  return 1 + elmx + elmy*(nx-1) + elmz*(ny-1)*(nx-1);
+}
+
+
 bool ASMs3DLag::evalSolution (Matrix& sField, const Vector& locSol,
                               const RealArray*, bool, int, int) const
 {

src/ASM/ASMs3DLag.h

@@ -81,6 +81,10 @@ public:
   //! \param[in] nSegSpan Number of visualization segments over each knot-span
   virtual bool getGridParameters(RealArray& prm, int dir, int nSegSpan) const;
 
+  //! \brief Find element for parameter, and optionally calculate local coordinates.
+  virtual int findElement(double u, double v, double w, double* xi = nullptr,
+                          double* eta = nullptr, double* zeta = nullptr) const;
+
 protected:
   //! \brief Assigned global coordinates for the given node.
   //! \param[in] inod 1-based node index local to current patch