linear-algebra/src/algebra.js

Efficient, high-performance linear algebra library

/**
 * @fileOverview  Basic arithmetic operations
 */




/**
 * Transpose this matrix.
 * @return {Matrix}
 */
Matrix.prototype.trans = function() {
  var thisData = this.data,
    rows = this.rows, 
    cols = this.cols;

  var row, col;

  var result = new Array(cols);

  for (col=0; col<cols; ++col) {
    result[col] = new Array(rows);
    
    for (row=0; row<rows; ++row) {
      result[col][row] = thisData[row][col];
    }
  }

  return new Matrix(result);
};






/**
 * In-place version of trans().
 * @return this
 */
Matrix.prototype.trans_ = function() {
  var thisData = this.data,
    rows = this.rows, 
    cols = this.cols;

  var row, col, t;

  // first we transpose the matrix upto length of shortest side
  var isSquare = (cols === rows);
  var shortestSide = (cols > rows) ? rows : cols;

  for (row=0; row<shortestSide; ++row) {
    for (col=row + 1; col<shortestSide; ++col) {
      t = thisData[col][row];
      thisData[col][row] = thisData[row][col];
      thisData[row][col] = t;
    }
  }

  // now we transpose the rest of the matrix
  if (!isSquare) {
    if (cols > rows) {
      // do a column at a time
      for (col=rows; cols > col; ++col) {
        if (!Array.isArray(thisData[col])) {
          thisData[col] = new Array(rows);
        }

        for (row=0; row<rows; ++row) {
          thisData[col][row] = thisData[row][col];
        }
      }
    }
    else {
      // do a row at a time
      for (row=cols; rows > row; ++row) {
        for (col=0; cols > col; ++col) {
          thisData[col][row] = thisData[row][col];
        }
      }
    }
    
    // finally, we update the "official" dimensions
    t = rows;
    this.rows = cols;
    this.cols = t;
  }


  return this;
};



BUILD(ALGEBRA_OP, div, thisData[row][col] / op2Data[row][col])
BUILD(ALGEBRA_OP, mul, thisData[row][col] * op2Data[row][col])
BUILD(ALGEBRA_OP, plus, thisData[row][col] + op2Data[row][col])
BUILD(ALGEBRA_OP, minus, thisData[row][col] - op2Data[row][col])