Added Shortest Job First Algorithm

scheduling/shortest_job_first_algorithm.py

@@ -0,0 +1,149 @@
+"""
+Shortest job remainig first
+Please note arrival time and burst
+Please use spaces to separate times entered.
+"""
+
+import pandas as pd
+from typing import List
+
+
+def calculate_waitingtime(
+    arrival_time: List[int], burst_time: List[int], no_of_processes: int
+) -> List[int]:
+
+    """
+    Calculate the waiting time of each processes
+    Return: list of waiting times.
+    >>> calculate_waitingtime([1,2,3,4],[3,3,5,1],4)
+    [0, 3, 5, 0]
+    >>> calculate_waitingtime([1,2,3],[2,5,1],3)
+    [0, 2, 0]
+    >>> calculate_waitingtime([2,3],[5,1],2)
+    [1, 0]
+    """
+    remaining_time = [0] * no_of_processes
+    waiting_time = [0] * no_of_processes
+    # Copy the burst time into remaining_time[]
+    for i in range(no_of_processes):
+        remaining_time[i] = burst_time[i]
+
+    complete = 0
+    increment_time = 0
+    minm = 999999999
+    short = 0
+    check = False
+
+    # Process until all processes are completed
+    while complete != no_of_processes:
+        for j in range(no_of_processes):
+            if arrival_time[j] <= increment_time:
+                if remaining_time[j] > 0:
+                    if remaining_time[j] < minm:
+                        minm = remaining_time[j]
+                        short = j
+                        check = True
+
+        if not check:
+            increment_time += 1
+            continue
+        remaining_time[short] -= 1
+
+        minm = remaining_time[short]
+        if minm == 0:
+            minm = 999999999
+
+        if remaining_time[short] == 0:
+            complete += 1
+            check = False
+
+            # Find finish time of current process
+            finish_time = increment_time + 1
+
+            # Calculate waiting time
+            finar = finish_time - arrival_time[short]
+            waiting_time[short] = finar - burst_time[short]
+
+            if waiting_time[short] < 0:
+                waiting_time[short] = 0
+
+        # Increment time
+        increment_time += 1
+    return waiting_time
+
+
+def calculate_turnaroundtime(
+    burst_time: List[int], no_of_processes: int, waiting_time: List[int]
+) -> List[int]:
+    """
+    Calculate the turn around time of each Processes
+    Return: list of turn around times.
+    >>> calculate_turnaroundtime([3,3,5,1], 4, [0,3,5,0])
+    [3, 6, 10, 1]
+    >>> calculate_turnaroundtime([3,3], 2, [0,3])
+    [3, 6]
+    >>> calculate_turnaroundtime([8,10,1], 3, [1,0,3])
+    [9, 10, 4]
+    """
+    turn_around_time = [0] * no_of_processes
+    for i in range(no_of_processes):
+        turn_around_time[i] = burst_time[i] + waiting_time[i]
+    return turn_around_time
+
+
+def calculate_average_times(
+    waiting_time: List[int], turn_around_time: List[int], no_of_processes: int
+):
+    """
+    This function calculates the average of the waiting & turnaround times
+    Prints: Average Waiting time & Average Turn Around Time
+    >>> calculate_average_times([0,3,5,0],[3,6,10,1],4)
+    Average waiting time = 2.00000
+    Average turn around time = 5.0
+    >>> calculate_average_times([2,3],[3,6],2)
+    Average waiting time = 2.50000
+    Average turn around time = 4.5
+    >>> calculate_average_times([10,4,3],[2,7,6],3)
+    Average waiting time = 5.66667
+    Average turn around time = 5.0
+    """
+    total_waiting_time = 0
+    total_turn_around_time = 0
+    for i in range(no_of_processes):
+        total_waiting_time = total_waiting_time + waiting_time[i]
+        total_turn_around_time = total_turn_around_time + turn_around_time[i]
+    print("Average waiting time = %.5f" % (total_waiting_time / no_of_processes))
+    print("Average turn around time =", total_turn_around_time / no_of_processes)
+
+
+if __name__ == "__main__":
+    print("Enter how many process you want to analyze")
+    no_of_processes = int(input())
+    burst_time = [0] * no_of_processes
+    arrival_time = [0] * no_of_processes
+    processes = list(range(1, no_of_processes + 1))
+
+    for i in range(no_of_processes):
+        print("Enter the arrival time and brust time for process:--" + str(i + 1))
+        arrival_time[i], burst_time[i] = map(int, input().split())
+    waiting_time = calculate_waitingtime(arrival_time, burst_time, no_of_processes)
+    bt = burst_time
+    n = no_of_processes
+    wt = waiting_time
+    turn_around_time = calculate_turnaroundtime(bt, n, wt)
+    calculate_average_times(waiting_time, turn_around_time, no_of_processes)
+    processes = list(range(1, no_of_processes + 1))
+    fcfs = pd.DataFrame(
+        list(zip(processes, burst_time, arrival_time, waiting_time, turn_around_time)),
+        columns=[
+            "Process",
+            "BurstTime",
+            "ArrivalTime",
+            "WaitingTime",
+            "TurnAroundTime",
+        ],
+    )
+
+    # Printing the dataFrame
+    pd.set_option("display.max_rows", fcfs.shape[0] + 1)
+    print(fcfs)