finishing touches on matrixMult.js

Maths/matrixMult.js

@@ -1,87 +1,87 @@
 
 // MatrixCheck tests to see if all of the rows of the matrix inputted have similar size columns
-const matrixCheck = (matrix)=>{
-  let columnNumb;
-  for (let index = 0; index < matrix.length; index++){
-    if (index == 0){
-      columnNumb = matrix[index].length;
-    } else if (matrix[index].length != columnNumb){
+const matrixCheck = (matrix) => {
+  let columnNumb
+  for (let index = 0; index < matrix.length; index++) {
+    if (index === 0) {
+      columnNumb = matrix[index].length
+    } else if (matrix[index].length !== columnNumb) {
       console.log('The columns in this array are not equal')
     } else {
-      return columnNumb;
+      return columnNumb
     }
   }
 }
 
 // tests to see if the matrices have a like side, i.e. the row length on the first matrix matches the column length on the second matrix, or vise versa.
-const twoMatricesCheck = (first, second)=>{
-  const [firstRowLength, secondRowLength, firstColLength, secondColLength] = [first.length, second.length, matrixCheck(first), matrixCheck(second)];
-    if (firstRowLength != secondColLength || secondRowLength != firstColLength){
-      console.log('These matrices do not have a common side');
-      return false;
-    } else {
-      return true;
-    }
+const twoMatricesCheck = (first, second) => {
+  const [firstRowLength, secondRowLength, firstColLength, secondColLength] = [first.length, second.length, matrixCheck(first), matrixCheck(second)]
+  if (firstRowLength !== secondColLength || secondRowLength !== firstColLength) {
+    console.log('These matrices do not have a common side')
+    return false
+  } else {
+    return true
+  }
 }
 
 // returns an empty array that has the same number of rows as the left matrix being multiplied.
-  //Uses Array.prototype.map() to loop over the first (or left) matrix and returns an empty array on each iteration.
-const initiateEmptyArray = (first, second)=>{
-  if (twoMatricesCheck(first, second)){
-    const emptyArray = first.map(()=>{
-      return [''];
+// Uses Array.prototype.map() to loop over the first (or left) matrix and returns an empty array on each iteration.
+const initiateEmptyArray = (first, second) => {
+  if (twoMatricesCheck(first, second)) {
+    const emptyArray = first.map(() => {
+      return ['']
     })
-    return emptyArray;
-  }else{
-    return false;
+    return emptyArray
+  } else {
+    return false
   }
 }
 
 // Finally, `matrixMult` uses `Array.prototype.push()`, multiple layers of nested `for` loops, the addition assignment `+=` operator and multiplication operator `*` to perform the dot product between two matrices of differing sizes.
-    // Dot product, takes the row of the first matrix and multiplies it by the column of the second matrix, the `twoMatricesCheck` tested to see if they were the same size already.
-    // The dot product for each iteration is then saved to its respective index into `multMatrix`.
-const matrixMult = (firstArray, secondArray)=>{
-  let multMatrix = initiateEmptyArray(firstArray, secondArray);
-  for (let rm = 0; rm < firstArray.length; rm++){
-    rowMult = [];
-    for (let col = 0; col < firstArray[0].length; col++){
-      rowMult.push(firstArray[rm][col]);
+// Dot product, takes the row of the first matrix and multiplies it by the column of the second matrix, the `twoMatricesCheck` tested to see if they were the same size already.
+// The dot product for each iteration is then saved to its respective index into `multMatrix`.
+const matrixMult = (firstArray, secondArray) => {
+  const multMatrix = initiateEmptyArray(firstArray, secondArray)
+  for (let rm = 0; rm < firstArray.length; rm++) {
+    const rowMult = []
+    for (let col = 0; col < firstArray[0].length; col++) {
+      rowMult.push(firstArray[rm][col])
     }
-    for (let cm = 0; cm < firstArray.length; cm++){
-      colMult = [];
-      for (let row = 0; row < secondArray.length; row++){
-        colMult.push(secondArray[row][cm]);
+    for (let cm = 0; cm < firstArray.length; cm++) {
+      const colMult = []
+      for (let row = 0; row < secondArray.length; row++) {
+        colMult.push(secondArray[row][cm])
       }
-      let newNumb = 0;
-      for (let index = 0; index < rowMult.length; index++){
-        newNumb += rowMult[index] * colMult[index];
+      let newNumb = 0
+      for (let index = 0; index < rowMult.length; index++) {
+        newNumb += rowMult[index] * colMult[index]
       }
-      multMatrix[rm][cm] = newNumb;
+      multMatrix[rm][cm] = newNumb
     }
   }
-  return multMatrix;
+  return multMatrix
 }
 
 const firstMatrix = [
   [1, 2],
   [3, 4]
-];
+]
 
 const secondMatrix = [
   [5, 6],
   [7, 8]
-];
+]
 
-console.log(matrixMult(firstMatrix, secondMatrix)); // [ [ 19, 22 ], [ 43, 50 ] ]
+console.log(matrixMult(firstMatrix, secondMatrix)) // [ [ 19, 22 ], [ 43, 50 ] ]
 
 const thirdMatrix = [
   [-1, 4, 1],
-  [7, -6, 2],
-];
+  [7, -6, 2]
+]
 const fourthMatrix = [
   [2, -2],
   [5, 3],
-  [3, 2],
-];
+  [3, 2]
+]
 
-console.log(matrixMult(thirdMatrix, fourthMatrix)); // [ [ 21, 16 ], [ -10, -28 ] ]
+console.log(matrixMult(thirdMatrix, fourthMatrix)) // [ [ 21, 16 ], [ -10, -28 ] ]