From 5fec65b24781cf2b882e60853375b230fc2a670a Mon Sep 17 00:00:00 2001 From: KylerSmith Date: Sat, 8 Jul 2017 20:10:43 -0700 Subject: [PATCH] Create Matrix data structure. --- .DS_Store | Bin 6148 -> 8196 bytes data_structures/Matrix/Matrix.java | 197 +++++++++++++++++++++++++++++ 2 files changed, 197 insertions(+) create mode 100644 data_structures/Matrix/Matrix.java diff --git a/.DS_Store b/.DS_Store index 4510cdaa3c92eed37289c2ac12b58a82591e3985..f28585d78e4c824a62c4e8ee30d752891efb7b22 100644 GIT binary patch literal 8196 zcmeHM-A)rh6h6a`Y(oSBCU9l;#>5LkAVdilQDFL7Yiu&g|~_&YAtr{Pb*zNR-;{8qpFFS*R@MrqTSS z@N=$1WlY~;umGOu4LNj7&Q1{3hP2HM!+>GHFkl!k3>XHk0s}a+xmY>pzItj}!+>Gn zzhr>-2OE`TQOmxPa_c}NQvk>b+?EA>#czu+q`N++w%8zP`R}Z`|uG+uhAgbnkDj^?H`IcxUb5&SCT9efLA}KYk6N4GGqYj_UVW_Nw}@&(#?{I5MGrFTdWIfjq&y3FHu-YYdE;ci z=@~H(tdDu@%C=6s(n6Ex(kTA}@45gR0eqjp%Dx^!NOj!vV50`0$m zNbaF!_&mbf`FKZORUUYV@vKP|8A0Z?o;Mm^o0&J-gN3ub+4~b4LmXN_c^FHK5jD`u zaLy;fK=db}&vPcpYBE=On%8ufNO6(b5kSS2D&uN2OPv32=YRjdQe!rQF$@?6E|&o@ zQLdCruzB`_Hfx@9Z5#Cvl?&_jm6Q-PG98DM={V&1ABO1LP-RR}%f6DhgYx%31Y}N2 QbN-V#|1UA~`$x|IpZ9>FN&o-= delta 206 zcmZp1XfcprU|?W$DortDU=RQ@Ie-{MGjUEV6q~50D9Q$s2aA<3lr!Wr6fvYQ6mKkC z&dA6%`H-Li7vl|}d<9Su`{X}@rmR6gmd0cr5pzzUID-ZdvrhIAv1WAxvSv)aB%;Rg z9||VBi0be#0@X8u>}31@e`Dc7mc{HG9D>Y1J`f0S0|{4 Rows: " + m1.getRows() + " Columns: " + m1.getColumns()); + System.out.println("m2 --> Rows: " + m2.getRows() + " Columns: " + m2.getColumns()); + System.out.println("m3 --> Rows: " + m3.getRows() + " Columns: " + m3.getColumns()); + + //check for reference issues + System.out.println("m2 -->\n" + m2); + data2[1][1] = 101; + System.out.println("m2 -->\n" + m2); + + //test equals + System.out.println("m2==null: " + m2.equals(null)); //false + System.out.println("m3==\"MATRIX\": " + m2.equals("MATRIX")); //false + System.out.println("m2==m1: " + m2.equals(m1)); //false + System.out.println("m2==m2: " + m2.equals(m2)); //true + System.out.println("m2==m3: " + m2.equals(m3)); //false + + //test operations (valid) + System.out.println("2 * m2:\n" + m2.scale(2)); + System.out.println("m2 + m3:\n" + m2.plus(m3)); + System.out.println("m2 - m3:\n" + m2.minus(m3)); + } + + + /** + * Data needs to be a deep copy as not to change the original state. + */ + private int[][] data; + + /** + * Constructor for the matrix takes in a 2D array + * + * @param pData + */ + public Matrix(int[][] pData) { + + /** Make a deep copy of the data */ + if(pData.length != 0) { + int[][] newData = new int[pData.length][pData[0].length]; + + for(int i = 0; i < pData.length; i++) + for(int j = 0; j < pData[0].length; j++) + newData[i][j] = pData[i][j]; + + this.data = newData; + } else { + this.data = null; + } + } + + /** + * Returns the element specified by the given location + * + * @param x : x cooridinate + * @param y : y cooridinate + * @return int : value at location + */ + public int getElement(int x, int y) { + return data[x][y]; + } + + /** + * Returns the number of rows in the Matrix + * + * @return rows + */ + public int getRows() { + if(this.data == null) + return 0; + + return data.length; + } + + /** + * Returns the number of rows in the Matrix + * + * @return columns + */ + public int getColumns() { + if(this.data == null) + return 0; + return data[0].length; + } + + /** + * Returns this matrix scaled by a factor. That is, computes sA where s is a + * constant and A is a matrix (this object). + * + * @param scalar : value to scale by + * @return A new matrix scaled by the scalar value + */ + public Matrix scale(int scalar) { + + int[][] newData = new int[this.data.length][this.data[0].length]; + + for (int i = 0; i < this.getRows(); ++i) + for(int j = 0; j < this.getColumns(); ++j) + newData[i][j] = this.data[i][j] * scalar; + + return new Matrix(newData); + } + + /** + * Adds this matrix to another matrix. + * + * @param other : Matrix to be added + * @return addend + */ + public Matrix plus(Matrix other) throws RuntimeException { + + int[][] newData = new int[this.data.length][this.data[0].length]; + + if(this.getRows() != other.getRows() || this.getColumns() != other.getColumns()) + throw new RuntimeException("Not the same size matrix."); + + for (int i = 0; i < this.getRows(); ++i) + for(int j = 0; j < this.getColumns(); ++j) + newData[i][j] = this.data[i][j] + other.getElement(i, j); + + return new Matrix(newData); + } + + /** + * Subtracts this matrix from another matrix. + * + * @param other : Matrix to be subtracted + * @return difference + */ + public Matrix minus(Matrix other) throws RuntimeException { + + int[][] newData = new int[this.data.length][this.data[0].length]; + + if(this.getRows() != other.getRows() || this.getColumns() != other.getColumns()) + throw new RuntimeException("Not the same size matrix."); + + for (int i = 0; i < this.getRows(); ++i) + for(int j = 0; j < this.getColumns(); ++j) + newData[i][j] = this.data[i][j] - other.getElement(i, j); + + return new Matrix(newData); + } + + /** + * Checks if the matrix passed is equal to this matrix + * + * @param other : the other matrix + * @return boolean + */ + public boolean equals(Matrix other) { + return this == other; + } + + /** + * Returns the Matrix as a String in the following format + * + * [ a b c ] ... + * [ x y z ] ... + * [ i j k ] ... + * ... + * + * @return Matrix as String + * TODO: Work formatting for different digit sizes + */ + public String toString() { + String str = ""; + + for(int i = 0; i < this.data.length; i++) { + str += "[ "; + for(int j = 0; j < this.data[0].length; j++) { + str += data[i][j]; + str += " "; + } + str += "]"; + str += "\n"; + } + + return str; + } +}