C++ VectorI::size方法代码示例

 void write_faces(std::ofstream& fout,
         const VectorI& faces,
         const size_t vertex_per_face,
         const VectorI& uv_indices=VectorI::Zero(0)) {
     if (vertex_per_face != 3 && vertex_per_face != 4) {
         std::stringstream err_msg;
         err_msg << "OBJ format does not support non-triangle non-quad face with "
             << vertex_per_face << " vertices." << std::endl;
         throw RuntimeError(err_msg.str());
     }
     const size_t num_faces = faces.size() / vertex_per_face;
     const size_t num_uvs = uv_indices.size() / 2;
     if (num_uvs == 0) {
         for (size_t i=0; i<num_faces; i++) {
             const auto& f = faces.segment(i*vertex_per_face, vertex_per_face);
             fout << "f";
             for (size_t j=0; j<vertex_per_face; j++) {
                 fout << " " << f[j] + 1;
             }
             fout << std::endl;
         }
     } else {
         for (size_t i=0; i<num_faces; i++) {
             const auto& f = faces.segment(i*vertex_per_face, vertex_per_face);
             const auto& uv = uv_indices.segment(i*vertex_per_face, vertex_per_face);
             fout << "f ";
             for (size_t j=0; j<vertex_per_face; j++) {
                 fout << f[j] + 1 << "/" << uv[j] + 1 << " ";
             }
             fout << std::endl;
         }
     }
 }

 bool match(HashGrid::Ptr grid, const Vector3F& v) {
     VectorI candidates = grid->get_items_near_point(v);
     if (candidates.size() != 1) {
         std::cout << "<" << v.transpose() << "> : " << candidates.transpose()
             << std::endl;
     }
     return candidates.size() > 0;
 }

 inline void assign_vector(
     VectorI &v_src,
     VectorI &v_ind,
     VectorI &v_val,
     VectorJ &v_out,
     Accum    accum)
 {
     using namespace detail;
     if (v_val.size() != v_ind.size())
     {
         return;
     }
     assign_vector_helper(v_src, v_ind, v_val.begin(), v_out, accum);
 }

ZSparseMatrix Assembler2D::getDisplacementStrainMatrix() {
    typedef Eigen::Triplet<double> T;
    std::vector<T> triplets;

    for (size_t i=0; i<m_mesh->getNbrElements(); i++) {
        Eigen::MatrixXd dN = m_DN[i];
        VectorI idx = m_mesh->getElement(i);
        assert(idx.size() == 3);
        double V = m_mesh->getElementVolume(i);

        // e_xx
        size_t row = i * 3;
        for (size_t k=0; k<3; k++) {
            triplets.push_back(T(row, idx[k]*2, dN(k,0)));
        }

        // e_yy
        row++;
        for (size_t k=0; k<3; k++) {
            triplets.push_back(T(row, idx[k]*2+1, dN(k,1)));
        }

        // e_xy
        row++;
        for (size_t k=0; k<3; k++) {
            triplets.push_back(T(row, idx[k]*2  , dN(k,1) / 2.0));
            triplets.push_back(T(row, idx[k]*2+1, dN(k,0) / 2.0));
        }
    }

    Eigen::SparseMatrix<double> B = Eigen::SparseMatrix<double>(3*m_mesh->getNbrElements(), 2*m_mesh->getNbrNodes());
    B.setFromTriplets(triplets.begin(), triplets.end());
    return ZSparseMatrix(B);
}

void Assembler2D::precomputeShapeFunctionDerivatives() {
    Eigen::MatrixXd selector = Eigen::MatrixXd::Zero(3,2);
    selector << 0.0, 0.0,
             1.0, 0.0,
             0.0, 1.0;

    m_DN.resize(m_mesh->getNbrElements());
    for (size_t i=0; i<m_mesh->getNbrElements(); ++i)
    {
        VectorI idx = m_mesh->getElement(i);
        assert(idx.size() == 3);
        VectorF u[3];
        u[0] = m_mesh->getNode(idx[0]);
        u[1] = m_mesh->getNode(idx[1]);
        u[2] = m_mesh->getNode(idx[2]);

        Eigen::MatrixXd P = Eigen::MatrixXd::Zero(3,3);
        P <<     1.0,     1.0,     1.0,
        u[0][0], u[1][0], u[2][0],
        u[0][1], u[1][1], u[2][1];

        // DN is a 4x3 matrix containing the gradients of the
        // 4 shape functions (one for each node)
        //
        m_DN[i] = P.inverse() * selector /* * -1.0 */;
    }
}

    std::vector<VectorI> enumerate(const VectorI& repetitions) {
        std::vector<VectorI> result;
        const size_t dim = repetitions.size();
        if (dim == 2) {
            for (size_t i=0; i<repetitions[0]; i++) {
                for (size_t j=0; j<repetitions[1]; j++) {
                    result.push_back(Vector2I(i,j));
                }
            }
        } else if (dim == 3) {
            for (size_t i=0; i<repetitions[0]; i++) {
                for (size_t j=0; j<repetitions[1]; j++) {
                    for (size_t k=0; k<repetitions[2]; k++) {
                        result.push_back(Vector3I(i,j,k));
                    }
                }
            }
        } else {
            std::stringstream err_msg;
            err_msg << "Unsupported dim: " << dim;
            throw NotImplementedError(err_msg.str());
        }

        return result;
    }

void VertexNormalAttribute::compute_vertex_normals_from_face(Mesh& mesh) {
    const size_t dim = mesh.get_dim();
    const size_t num_vertices = mesh.get_num_vertices();
    const size_t num_faces    = mesh.get_num_faces();
    const size_t vertex_per_face = mesh.get_vertex_per_face();

    const VectorF& normals = get_attribute(mesh, "face_normal");
    const VectorF& areas = get_attribute(mesh, "face_area");
    assert(normals.size() == 3 * num_faces);
    assert(areas.size() == num_faces);

    VectorF& v_normals = m_values;
    v_normals = VectorF::Zero(dim * num_vertices);

    for (size_t i=0; i<num_faces; i++) {
        VectorI face = mesh.get_face(i);
        assert(face.size() == vertex_per_face);
        VectorF face_normal = normals.segment(i*dim, dim);
        Float face_area = areas[i];
        for (size_t j=0; j<vertex_per_face; j++) {
            size_t vi = face[j];
            v_normals.segment(vi*dim, dim) += face_normal * face_area;
        }
    }

    for (size_t i=0; i<num_vertices; i++) {
        VectorF n = v_normals.segment(dim*i, dim);
        Float n_len = n.norm();
        if (n_len > 0.0) n /= n_len;
        v_normals.segment(dim*i, dim) = n;
    }
}

VectorF Assembler::getCurlNorm(double* vector_field, int num_vector_field) {
    size_t num_node = m_mesh->getNbrNodes();
    size_t num_elem = m_mesh->getNbrElements();
    size_t dim = m_mesh->getDim();

    assert(num_vector_field == dim*num_node);

    VectorF curl_norm(num_elem);

    for (size_t i=0; i<num_elem; i++) {
        VectorI elem = m_mesh->getElement(i);
        const Eigen::MatrixXd& DN = m_DN[i];
        Eigen::Vector3d curl(0, 0, 0);
        for (size_t j=0; j<elem.size(); j++) {
            Eigen::Vector3d v(0, 0, 0);
            Eigen::Vector3d grad(0, 0, 0);
            for (size_t k=0; k<dim; k++) {
                v[k] = vector_field[elem[j]*dim+k];
                grad[k] = DN(j, k);
            }

            curl = curl + grad.cross(v);
        }
        curl_norm[i] = curl.norm();
    }
    return curl_norm;
}

ZSparseMatrix Assembler2D::getLaplacianMatrix() {
    typedef Eigen::Triplet<double> T;
    std::vector<T> triplets;

    for (size_t i=0; i<m_mesh->getNbrElements(); ++i)
    {
        VectorI idx = m_mesh->getElement(i);
        assert(idx.size() == 3);

        Eigen::MatrixXd& dN = m_DN[i];

        // Small strain-displacement matrix
        //
        Eigen::MatrixXd B(2,3);
        B << dN(0,0), dN(1,0), dN(2,0),
        dN(0,1), dN(1,1), dN(2,1);

        Eigen::MatrixXd k_el = B.transpose() * B * m_mesh->getElementVolume(i);

        for (size_t j=0; j<3; ++j)
            for (size_t k=0; k<3; ++k)
                triplets.push_back(T(idx[j], idx[k], k_el(j,k)));
    }

    Eigen::SparseMatrix<double> L = Eigen::SparseMatrix<double>(m_mesh->getNbrNodes(), m_mesh->getNbrNodes());
    L.setFromTriplets(triplets.begin(), triplets.end());
    return ZSparseMatrix(L);
}

void Deform::set_soft_ctrs(const VectorF &T, const VectorI &idx_T)
{
    assert(T.size()/3 == idx_T.size());

    for (int i = 0, i_end = idx_T.size(); i < i_end; ++ i)
    {
        int cid = idx_T[i];

        Eigen::Vector3f ctr; 
        ctr << T[3*i], T[3*i+1], T[3*i+2];

        soft_ctrs.push_back(Constraint(ctr, cid));
    }

    std::sort(soft_ctrs.begin(), soft_ctrs.end(), ConstraintCompare());
}

 VectorI map_indices(const VectorI& face, const VectorI& index_map) {
     const size_t vertex_per_face = face.size();
     VectorI index(vertex_per_face);
     for (size_t i=0; i<vertex_per_face; i++) {
         index[i] = index_map[face[i]];
     }
     return index;
 }

Float ElementWiseMaterial::get_material_tensor(
        size_t i, size_t j, size_t k, size_t l, VectorF coord) const {
    const VectorI voxel_ids = look_up_voxels(coord);
    assert(voxel_ids.size() > 0);
    const size_t voxel_id = voxel_ids[0];
    assert(voxel_id < m_materials.size());
    return m_materials[voxel_id]->get_material_tensor(i,j,k,l,coord);
}

MatrixF ElementWiseMaterial::strain_to_stress(
        const MatrixF& strain, VectorF coord) const {
    const VectorI voxel_ids = look_up_voxels(coord);
    assert(voxel_ids.size() > 0);
    const size_t voxel_id = voxel_ids[0];
    assert(voxel_id < m_materials.size());
    return m_materials[voxel_id]->strain_to_stress(strain, coord);
}

void MeshGeometry::extract_faces_from_hexes() {
    const VectorI& voxels = m_voxels;
    typedef std::map<Multiplet, int> FaceCounter;
    FaceCounter face_counter;

    for (size_t i=0; i<voxels.size(); i+= m_vertex_per_voxel) {
        VectorI voxel = voxels.segment(i, m_vertex_per_voxel);
        // Note that the order of vertices below are predefined by MSH format,
        // each face should have normal pointing outward.
        assert(voxel.size() == 8);
        Multiplet voxel_faces[6] = {
            Multiplet(Vector4I(voxel[0], voxel[1], voxel[5], voxel[4])), // Bottom
            Multiplet(Vector4I(voxel[2], voxel[3], voxel[7], voxel[6])), // Top
            Multiplet(Vector4I(voxel[0], voxel[4], voxel[7], voxel[3])), // Left
            Multiplet(Vector4I(voxel[1], voxel[2], voxel[6], voxel[5])), // Right
            Multiplet(Vector4I(voxel[4], voxel[5], voxel[6], voxel[7])), // Front
            Multiplet(Vector4I(voxel[0], voxel[3], voxel[2], voxel[1]))  // Back
        };

        for (size_t j=0; j<6; j++) {
            if (face_counter.find(voxel_faces[j]) == face_counter.end()) {
                face_counter[voxel_faces[j]] = 1;
            } else {
                face_counter[voxel_faces[j]] += 1;
            }
        }
    }

    std::vector<int> vertex_buffer;
    for (FaceCounter::const_iterator itr = face_counter.begin();
            itr!=face_counter.end(); itr++) {
        if (itr->second != 1 && itr->second != 2) {
            const Vector4I& face = itr->first.get_ori_data();
            std::stringstream err_msg;
            err_msg << "Non-manifold mesh detected!" << std::endl;
            err_msg << "Face <"
                << face[0] << ", "
                << face[1] << ", "
                << face[2] << ", "
                << face[3] << "> has "
                << itr->second << " adjacent volume elements";
            throw RuntimeError(err_msg.str());
        }
        if (itr->second == 1) {
            const VectorI& f = itr->first.get_ori_data();
            assert(f.size() == 4);
            vertex_buffer.push_back(f[0]);
            vertex_buffer.push_back(f[1]);
            vertex_buffer.push_back(f[2]);
            vertex_buffer.push_back(f[3]);
        }
    }

    m_faces.resize(vertex_buffer.size());
    std::copy(vertex_buffer.begin(), vertex_buffer.end(), m_faces.data());
    m_vertex_per_face = 4;
}

ALGEB minpoly(MKernelVector kv, ALGEB* args)
  {
    int i;
    ALGEB retlist, blank;
    char err[] = "ERROR!  Associated blackbox object does not exist!";
    int key = MapleToInteger32(kv,args[1]), flag;
    std::map<int,int>::iterator f_i;
    std::map<int,void*>::iterator h_i;

    // Get the data from the hash table
    f_i = typeTable.find(key);
    if( f_i == typeTable.end() )
      MapleRaiseError(kv,err);
    else
      flag = f_i->second;


    h_i = hashTable.find(key);
    if(h_i != hashTable.end() ) { // We've got data
      switch( flag ) {
	// Getting the minimal polynomial is rather complicated, so both instances of this code were
	// wrapped up inside a block, to cut down at the clutter at the top of this function.
	// First declares a vector of the proper type and casts the pointer.  Then computes the minimal
	// polynomial.  It then builds the proper Maple list structure for this application.


         case BlackBoxi: {
	   Vectorl mpreturn;
	    Vectorl::iterator mp_i;
	    TriplesBBi* BB = (TriplesBBi*) h_i->second;
	    LinBox::minpoly( mpreturn, *BB, BB->field() );
	    retlist = MapleListAlloc(kv, mpreturn.size() );
	    for(i = 1, mp_i = mpreturn.begin(); mp_i != mpreturn.end(); ++mp_i, ++i)
	      MapleListAssign(kv, retlist, i, ToMapleInteger(kv, *mp_i));
	 }
	 break;

         case BlackBoxI: {
	   VectorI mpreturn;
	   VectorI::iterator mp_i;
	   TriplesBBI* BB = (TriplesBBI*) h_i->second;
	   LinBox::minpoly( mpreturn, *BB, BB->field() );
	   retlist = MapleListAlloc(kv, mpreturn.size());
	   for(i = 1, mp_i = mpreturn.begin(); mp_i != mpreturn.end(); ++mp_i, ++i)
	     MapleListAssign(kv, retlist, i, LiToM(kv, *mp_i, blank));

	 }
	 break;
      }
    }
    else
      MapleRaiseError(kv,err);

    return retlist;

  }