@rayyamhk/matrix/lib/core/utils/submatrix.js

A professional, comprehensive and high-performance library for you to manipulate matrices.

"use strict";

function _slicedToArray(arr, i) { return _arrayWithHoles(arr) || _iterableToArrayLimit(arr, i) || _unsupportedIterableToArray(arr, i) || _nonIterableRest(); }

function _nonIterableRest() { throw new TypeError("Invalid attempt to destructure non-iterable instance.\nIn order to be iterable, non-array objects must have a [Symbol.iterator]() method."); }

function _unsupportedIterableToArray(o, minLen) { if (!o) return; if (typeof o === "string") return _arrayLikeToArray(o, minLen); var n = Object.prototype.toString.call(o).slice(8, -1); if (n === "Object" && o.constructor) n = o.constructor.name; if (n === "Map" || n === "Set") return Array.from(o); if (n === "Arguments" || /^(?:Ui|I)nt(?:8|16|32)(?:Clamped)?Array$/.test(n)) return _arrayLikeToArray(o, minLen); }

function _arrayLikeToArray(arr, len) { if (len == null || len > arr.length) len = arr.length; for (var i = 0, arr2 = new Array(len); i < len; i++) { arr2[i] = arr[i]; } return arr2; }

function _iterableToArrayLimit(arr, i) { var _i = arr == null ? null : typeof Symbol !== "undefined" && arr[Symbol.iterator] || arr["@@iterator"]; if (_i == null) return; var _arr = []; var _n = true; var _d = false; var _s, _e; try { for (_i = _i.call(arr); !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"] != null) _i["return"](); } finally { if (_d) throw _e; } } return _arr; }

function _arrayWithHoles(arr) { if (Array.isArray(arr)) return arr; }

function _typeof(obj) { "@babel/helpers - typeof"; if (typeof Symbol === "function" && typeof Symbol.iterator === "symbol") { _typeof = function _typeof(obj) { return typeof obj; }; } else { _typeof = function _typeof(obj) { return obj && typeof Symbol === "function" && obj.constructor === Symbol && obj !== Symbol.prototype ? "symbol" : typeof obj; }; } return _typeof(obj); }

var _require = require('../../Error'),
    INVALID_MATRIX = _require.INVALID_MATRIX,
    EXPECTED_STRING_NUMBER_AT_POS_1_2 = _require.EXPECTED_STRING_NUMBER_AT_POS_1_2,
    INVALID_ROW = _require.INVALID_ROW,
    INVALID_COLUMN = _require.INVALID_COLUMN,
    OVERFLOW_ROW = _require.OVERFLOW_ROW,
    INVALID_ROWS_EXPRESSION = _require.INVALID_ROWS_EXPRESSION,
    INVALID_COLUMNS_EXPRESSION = _require.INVALID_COLUMNS_EXPRESSION,
    OVERFLOW_COLUMN = _require.OVERFLOW_COLUMN;
/**
 * Generates a submatrix of a matrix.
 * @memberof Matrix
 * @static
 * @param {Matrix} A - Any matrix
 * @param {string|number} rows - Rows expression
 * @param {string|number} cols - Columns expression
 * @returns {Matrix} Submatrix of A
 */


function submatrix(A, rows, cols) {
  if (!(A instanceof this)) {
    throw new Error(INVALID_MATRIX);
  }

  var arg1Type = _typeof(rows);

  var arg2Type = _typeof(cols);

  if (arg1Type !== 'string' && arg1Type !== 'number' || arg2Type !== 'string' && arg2Type !== 'number') {
    throw new Error(EXPECTED_STRING_NUMBER_AT_POS_1_2);
  }

  var _A$size = A.size(),
      _A$size2 = _slicedToArray(_A$size, 2),
      row = _A$size2[0],
      col = _A$size2[1];

  var rowStart;
  var rowEnd;
  var colStart;
  var colEnd;

  if (arg1Type === 'number') {
    if (!Number.isInteger(rows) || rows < 0) {
      throw new Error(INVALID_ROW);
    }

    if (rows >= row) {
      throw new Error(OVERFLOW_ROW);
    }

    rowStart = rows;
    rowEnd = rows;
  } else {
    // string
    var arg = rows.split(':');

    if (arg.length !== 2) {
      throw new Error(INVALID_ROWS_EXPRESSION);
    }

    var _arg = _slicedToArray(arg, 2),
        r1 = _arg[0],
        r2 = _arg[1];

    if (r1 === '') {
      rowStart = 0;
    } else {
      var r = Number(r1);

      if (!Number.isInteger(r) || r < 0) {
        throw new Error(INVALID_ROW);
      }

      if (r >= row) {
        throw new Error(OVERFLOW_ROW);
      }

      rowStart = r;
    }

    if (r2 === '') {
      rowEnd = row - 1;
    } else {
      var _r = Number(r2);

      if (!Number.isInteger(_r) || _r < 0) {
        throw new Error(INVALID_ROW);
      }

      if (_r >= row) {
        throw new Error(OVERFLOW_ROW);
      }

      rowEnd = _r;
    }

    if (rowStart > rowEnd) {
      throw new Error(INVALID_ROWS_EXPRESSION);
    }
  }

  if (arg2Type === 'number') {
    if (!Number.isInteger(cols) || cols < 0) {
      throw new Error(INVALID_COLUMN);
    }

    if (cols >= col) {
      throw new Error(OVERFLOW_COLUMN);
    }

    colStart = cols;
    colEnd = cols;
  } else {
    // string
    var _arg2 = cols.split(':');

    if (_arg2.length !== 2) {
      throw new Error(INVALID_COLUMNS_EXPRESSION);
    }

    var _arg3 = _slicedToArray(_arg2, 2),
        c1 = _arg3[0],
        c2 = _arg3[1];

    if (c1 === '') {
      colStart = 0;
    } else {
      var c = Number(c1);

      if (!Number.isInteger(c) || c < 0) {
        throw new Error(INVALID_COLUMN);
      }

      if (c >= col) {
        throw new Error(OVERFLOW_COLUMN);
      }

      colStart = c;
    }

    if (c2 === '') {
      colEnd = col - 1;
    } else {
      var _c = Number(c2);

      if (!Number.isInteger(_c) || _c < 0) {
        throw new Error(INVALID_COLUMN);
      }

      if (_c >= col) {
        throw new Error(OVERFLOW_COLUMN);
      }

      colEnd = _c;
    }

    if (colStart > colEnd) {
      throw new Error(INVALID_COLUMNS_EXPRESSION);
    }
  }

  var matrix = A._matrix;
  var subRow = rowEnd - rowStart + 1;
  var subCol = colEnd - colStart + 1;
  var subMatrix = new Array(subRow);

  for (var i = rowStart; i <= rowEnd; i++) {
    var newRow = new Array(subCol);

    for (var j = colStart; j <= colEnd; j++) {
      newRow[j - colStart] = matrix[i][j];
    }

    subMatrix[i - rowStart] = newRow;
  }

  return new this(subMatrix);
}

;
module.exports = submatrix;