From 0958256e0b795c73f154ffb20d484d85b0b015f5 Mon Sep 17 00:00:00 2001
From: ancarola <raffaele.ancarola@epfl.ch>
Date: Fri, 28 Jun 2019 02:32:59 +0200
Subject: Optimising matrices access and operations Creating the K-diagonal
 matrix

---
 include/mm/experiments/mmdiag_matrix.hpp | 159 +++++++++++++++++++++++++++++++
 1 file changed, 159 insertions(+)
 create mode 100644 include/mm/experiments/mmdiag_matrix.hpp

(limited to 'include/mm/experiments/mmdiag_matrix.hpp')

diff --git a/include/mm/experiments/mmdiag_matrix.hpp b/include/mm/experiments/mmdiag_matrix.hpp
new file mode 100644
index 0000000..124e4b3
--- /dev/null
+++ b/include/mm/experiments/mmdiag_matrix.hpp
@@ -0,0 +1,159 @@
+#pragma once
+
+namespace mm {
+
+    template<typename T>
+    class diag_component;
+
+    template<typename T, std::size_t N>
+    class multi_diag_matrix;
+}
+
+/*
+ * Optimized case of square matrix
+ * It's a matrix only composed by a diagonal 
+ */
+
+template<class T>
+class mm::diag_component
+{
+public:
+    virtual int dimension() const = 0;
+};
+
+template<class T, std::size_t N>
+class mm::diag_vector
+{
+public:
+
+    // TODO, define constructor
+
+    virtual int dimension() const override
+    {
+        return N;
+    }
+
+private:
+    std::array<T, N - ((Diag < 0) ? -Diag : Diag)> vector;
+};
+
+template<typename T, std::size_t N>
+class mm::multi_diag_matrix {
+public:
+    using type = T;
+
+    template<typename U, std::size_t N>
+    friend class mm::multi_diag_matrix;
+
+    multi_diag_matrix() : shared_zero(0) {}
+    ~multi_diag_matrix();
+
+    // copyable and movable
+    multi_diag_matrix(const multi_diag_matrix<T, N>& other);
+    multi_diag_matrix(multi_diag_matrix<T, N>&& other);
+
+    // copy from another matrix
+    template<std::size_t N>
+    multi_diag_matrix(const multi_diag_matrix<T, N>& other);
+
+    // standard access data
+    T& at(std::size_t row, std::size_t col);
+    const T& at(std::size_t row, std::size_t col) const;
+
+    // allows to access a matrix M at row j col k with M[j][k]
+    auto operator[](std::size_t index);
+
+    // swap two diagonals
+    void swap_diags(std::size_t k, std::size_t l);
+
+    // diagonal construction or substitution
+    template<int Diag, int K = N - ((Diag < 0) ? -Diag : Diag)>
+    void put_diag(const mm::diag_vector<T, K>& diag)
+    {
+        //static_assert((Diag <= -N) || (Diag >= N),
+        static_assert(K < 1,
+            "Diagonal number must be bounded between ]-N,N[")
+
+        auto exist = diagonals.find(Diag);
+
+        if (exist != diagonals.end())
+            // copy
+            *exists = diag;
+        else
+            // create and copy
+            diagonals.insert(new mm::diag_vector<T, K>(diag));
+    }
+
+    // mathematical operations
+    virtual multi_diag_matrix<T, N> transposed() const;
+    inline multi_diag_matrix<T, N> td() const { return transposed(); }
+
+    // multiplication rhs and lhs
+    // TODO, need super class matrix abstraction and auto return type
+
+    // A * M, TODO abstraction virtual method
+    template <std::size_t Rows>
+    basic_matrix<Rows, N> rhs_mult(const mm::basic_matrix<T, Rows, N>& A) const;
+
+    // M * A, TODO abstraction virtual method
+    template <std::size_t Cols>
+    basic_matrix<N, Cols> lhs_mult(const mm::basic_matrix<T, N, Cols>& A) const;
+
+protected:
+    template<typename ConstIterator>
+    multi_diag_matrix(ConstIterator begin, ConstIterator end);
+
+private:
+    // return an arbitrary zero in non-const mode
+    T shared_zero;
+
+    // ordered set of diagonals
+    std::unordered_map<int, mm::diag_component<T>*> diagonals;
+};
+
+template<typename T, std::size_t N>
+T& mm::multi_diag_matrix<T, N>::at(std::size_t row, std::size_t col) {
+    assert(row < N); // "out of row bound"
+    assert(col < N); // "out of column bound"
+
+    const int k = row - col; 
+    auto diag = diagonals.find(k);
+    const int line = (k > 0) ? col : row;
+
+    return (diag == diagonals.end()) ? (shared_zero = 0) : (*diag)[line];
+}
+
+template<typename T, std::size_t N>
+const T& mm::multi_diag_matrix<T, N>::at(std::size_t row, std::size_t col) const {
+    assert(row < N); // "out of row bound"
+    assert(col < N); // "out of column bound"
+
+    const int k = row - col;
+    auto diag = diagonals.find(k);
+    const int line = (k > 0) ? col : row;
+
+    return (diag == diagonals.end()) ? 0 : (*diag)[line];
+}
+
+template<typename T, std::size_t N>
+auto mm::multi_diag_matrix<T, N>::operator[](std::size_t index) {
+    assert(index < N)
+    
+    // TODO, single row mapping
+}
+
+template <typename T, std::size_t N, std::size_t Rows>
+mm::basic_matrix<Rows, N> mm::multi_diag_matrix<T, N>::rhs_mult(const mm::basic_matrix<T, Rows, N>& A) const
+{
+    // TODO
+}
+
+template <typename T, std::size_t N, std::size_t Cols>
+mm::basic_matrix<N, Cols> mm::multi_diag_matrix<T, N>::lhs_mult(const mm::basic_matrix<T, N, Cols>& A) const
+{
+    mm::basic_matrix<N, Cols> out;
+
+
+}
+
+
-- 
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