GY-63_MS5611/libraries/SparseMatrix

SparseMatrix

Arduino library for sparse matrices.

Description

SparseMatrix is an experimental library to implement sparse matrices on an Arduino.

The maximum matrix that can be represented is 255 x 255 with a maximum of 255 non-zero elements. This would just fit in an UNO's 2K memory.

The library does not hold the dimensions of the matrix (at least in 0.1.0)

The purpose of the library is efficient storage in memory. It does not do math operations except sum().

Relates to https://github.com/RobTillaart/distanceTable

Implementation

The implementation is based on 3 arrays holding x, y, value where value is float. In the future other datatypes should be possible.

Performance

The elements are not kept sorted or indexed so optimizations are possible but not investigated yet.

Interface

• SparseMatrix(uint8_t size) constructor. Parameter is the maximum number of elements in the sparse matrix.
• uint8_t size() maximum number of elements.
• uint8_t count() current number of elements in the matrix.
• float sum() sum of all elements ( > 0 ) in the matrix.
• void clear() resets the matrix to all zero's again.
• bool set(uint8_t x, uint8_t y, float value) gives an element in the matrix a value. If the value is set to zero, it is removed from the internal store. Returns false if the internal store is full, true otherwise.
• float get(uint8_t x, uint8_t y) returns the value in the matrix.
• bool add(uint8_t x, uint8_t y, float value) adds a value to an element in the matrix. If needed a new internal element is created. If the sum is zero, the element is removed from the internal store. Returns false if the internal store is full, true otherwise.

Future

• documentation
• test
• template version to store other data types
  • 1, 2, 3 (RGB), 4 byte integer or 8 byte doubles
  • struct, complex number
  • etc
• add examples
  • 2D histogram e.g. temperature vs humidity
  • N queens game.
• investigate optimizations.
• should set() and add() return the number of free places?
  • no hard code and more informative than just a bool.
• can set() and add() be merged?
• add link in distanceTable repo
• uint16_t size for larger platforms.
  • max matrix still 255 x 255 but more elements <> 0.

new functions

• walk through the elements?
  • first -> next; last -> prev.

won't

• math
  • determinant?
  • M x M
  • diagonal?
• add examples
  • battleship game
  • minesweeper game
  • nice exercise