|
| 1 | + |
| 2 | +# Exercise in Excel to Find Final Solution Using Hungarian Method |
| 3 | + |
| 4 | + |
| 5 | +### Problem Statement |
| 6 | + |
| 7 | + In a factory there are 4 different cutting machines. 4 tasks must be processed daily. |
| 8 | + Tasks can be performed on any of the machines. The table below represents the processing times, in hours, of each task on each of the machines. |
| 9 | + Designate a machine for each task in such a way as to minimize the total time spent. |
| 10 | + |
| 11 | +<br> |
| 12 | + |
| 13 | +## Step 1: Input the Cost Matrix in Excel |
| 14 | + |
| 15 | +<br> |
| 16 | + |
| 17 | + |
| 18 | +Enter the processing times (hours) in a 4x4 grid (cells `B2:E5`): |
| 19 | + |
| 20 | +<br> |
| 21 | + |
| 22 | +| Machine \ Task | Task 1 | Task 2 | Task 3 | Task 4 | |
| 23 | +|----------------|--------|--------|--------|--------| |
| 24 | +| **Machine 1** | 5 | 24 | 13 | 7 | |
| 25 | +| **Machine 2** | 10 | 25 | 3 | 23 | |
| 26 | +| **Machine 3** | 28 | 9 | 8 | 5 | |
| 27 | +| **Machine 4** | 10 | 17 | 15 | 3 | |
| 28 | + |
| 29 | + |
| 30 | +<br><br> |
| 31 | + |
| 32 | + |
| 33 | +## Step 2: Row Reduction |
| 34 | + |
| 35 | +<br> |
| 36 | + |
| 37 | +Subtract the minimum value in each row from all elements in that row. |
| 38 | + |
| 39 | +<br> |
| 40 | + |
| 41 | +1. **Row Minimums**: |
| 42 | + - **Machine 1**: `=MIN(B2:E2)` → **5** |
| 43 | + - **Machine 2**: `=MIN(B3:E3)` → **3** |
| 44 | + - **Machine 3**: `=MIN(B4:E4)` → **5** |
| 45 | + - **Machine 4**: `=MIN(B5:E5)` → **3** |
| 46 | + |
| 47 | + |
| 48 | + <br> |
| 49 | + |
| 50 | +2. **Row-Reduced Matrix** (cells `G2:J5`): |
| 51 | + - **Machine 1**: `=B2-$F2` → `0, 19, 8, 2` |
| 52 | + - **Machine 2**: `=B3-$F3` → `7, 22, 0, 20` |
| 53 | + - **Machine 3**: `=B4-$F4` → `23, 4, 3, 0` |
| 54 | + - **Machine 4**: `=B5-$F5` → `7, 14, 12, 0` |
| 55 | + |
| 56 | + |
| 57 | + |
| 58 | +<br><br> |
| 59 | + |
| 60 | + |
| 61 | +## Step 3: Column Reduction |
| 62 | + |
| 63 | +<br> |
| 64 | + |
| 65 | +Subtract the minimum value in each column from all elements in that column. |
| 66 | + |
| 67 | +<br> |
| 68 | + |
| 69 | +1. **Column Minimums** (cells `G6:J6`): |
| 70 | + - **Task 1**: `=MIN(G2:G5)` → **0** |
| 71 | + - **Task 2**: `=MIN(H2:H5)` → **4** |
| 72 | + - **Task 3**: `=MIN(I2:I5)` → **0** |
| 73 | + - **Task 4**: `=MIN(J2:J5)` → **0** |
| 74 | + |
| 75 | + <br> |
| 76 | + |
| 77 | +2. **Column-Reduced Matrix** (cells `K2:N5`): |
| 78 | + - **Task 1**: `=G2-$G$6` → `0, 7, 23, 7` |
| 79 | + - **Task 2**: `=H2-$H$6` → `15, 18, 0, 10` |
| 80 | + - **Task 3**: `=I2-$I$6` → `8, 0, 3, 12` |
| 81 | + - **Task 4**: `=J2-$J$6` → `2, 20, 0, 0` |
| 82 | + |
| 83 | + |
| 84 | +<br><br> |
| 85 | + |
| 86 | + |
| 87 | + |
| 88 | +## Step 4: Cover Zeros with Minimum Lines |
| 89 | + |
| 90 | +<br> |
| 91 | + |
| 92 | +Use Excel’s **conditional formatting** to highlight zeros. Draw lines to cover all zeros: |
| 93 | + |
| 94 | +<br> |
| 95 | + |
| 96 | +- **Row 1**: Task 1 (0) |
| 97 | +- **Row 2**: Task 3 (0) |
| 98 | +- **Row 3**: Task 4 (0) |
| 99 | +- **Row 4**: Task 4 (0) |
| 100 | + |
| 101 | +**Result**: 4 lines (equal to matrix size), so proceed to assignment. |
| 102 | + |
| 103 | +<br><br> |
| 104 | + |
| 105 | +## Step 5: Optimal Assignment |
| 106 | + |
| 107 | +<br> |
| 108 | + |
| 109 | +Assign tasks to machines where zeros are located: |
| 110 | + |
| 111 | +<br> |
| 112 | + |
| 113 | +| Machine | Task Assigned | Time | |
| 114 | +|----------|---------------|------| |
| 115 | +| **1** | Task 1 | 5 | |
| 116 | +| **2** | Task 3 | 3 | |
| 117 | +| **3** | Task 4 | 5 | |
| 118 | +| **4** | Task 2 | 17 | |
| 119 | + |
| 120 | +**Total Time**: \(5 + 3 + 5 + 17 = 30\) |
| 121 | + |
| 122 | + |
| 123 | +<br><br> |
| 124 | + |
| 125 | + |
0 commit comments