from the initial node with starting time of the project as zero. Proceed through the network visiting nodes in an increasing order of node number and end at the final node of the network. At each node, we calculate earliest start times for each activity by considering E i as the earliest occurrence of node i. The method may be summarized as below: Step : Set E = ; i = (initial node).
Step : Set the earliest start time(EST) for each activity that begins at node i as ES ij = E i ; for all activities ( i, j ) that start at node i. Step : Compute the earliest finish time (EFT) of each activity that begins at node i by adding the earliest start time of the activity to the duration of the activity. Thus EF ij = ES ij + t ij = E i + t ij . Step : Move on to next node, say node j ( j > i ) and compute the earliest start time at node j , using max max E i EF E t j ij ij , for all immediate predecessor activities.
Step : If j = n (final node), then the earliest finish time for the project is given by max max E EF E t ij ij , . Backward pass calculations: We start from the final (last) node n of the network, proceed through the network visiting nodes in the decreasing order of node numbers and end at the initial node . At each node, we calculate the latest finish time and latest start time for each activity by considering L j as the latest occurrence of node j . The method may be summarized below: Step : ; L E for j = n Step : Set the latest finish time (LFT)of each activity that ends at node j as LF L ij j Step : Compute the latest start time (LST) of all activities ending at node j , subtracting the duration of each activity from the