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The Doctor Rostering Problem - Asser Fahrenholz

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Chapter 7. Tests, results and discussion 47<br />

<strong>The</strong> enumeration<br />

Table 7.8: RCL Effect: All tests<br />

RCL Z(S) V(S)<br />

GRASP 1 4,125 28,53125<br />

50 5,5 21,98125<br />

100 356,1875 20,34375<br />

<strong>The</strong> enumeration changes the way the construction heuristic builds the initial solution.<br />

Thus, in the following, we shall, as in the previous section, only focus on how GRASP<br />

performs with and without the enumeration mechanism.<br />

Table 7.9: Enumeration effect: All tests<br />

Z(S) V(S)<br />

Test Day Shift Day Shift<br />

0 112,6667 155,2917 5,625 38,625<br />

1 112,625 137,25 9,458333 48,79167<br />

2 73,125 103,3333 7,916667 32,08333<br />

3 131 186,3333 8,291667 44,45833<br />

4 205,375 288,3333 9 82,54167<br />

5 133,2917 188,75 10,75 47,75<br />

6 52,45833 73,91667 3,125 18,25<br />

7 141,2917 204,7917 7,208333 61,125<br />

8 52,66667 77,08333 2,291667 26,75<br />

9 2,416667 6,75 0 8,333333<br />

From table 7.9, I conclude that the enumeration improves the performance of grasp<br />

considerably. For all instances, it is the case that the average solution of GRASP with<br />

enumeration is superior to the average solutions of GRASP without enumeration. To<br />

highlight the effect, see table 7.10 and 7.11 respectively. <strong>The</strong>se two tables, for RCL 1<br />

and RCL 50 respectively, shows the effect of the enumeration to a great extend. Espe-<br />

cially, table 7.11, where 50% randomisation has been implemented in the construction<br />

mechanism, the enumeration still ensures low average values of V(S).<br />

RCL 1<br />

GRASP Z(S) V(S)<br />

Day 3 0,125<br />

Shift 5,75 110<br />

4,375 55,0625<br />

Table 7.10: Enumeration effect:<br />

Test 4, RCL 1<br />

RCL 50<br />

GRASP Z(S) V(S)<br />

Day 7,875 5,375<br />

Shift 5,625 53,375<br />

6,75 29,375<br />

Table 7.11: Enumeration effect:<br />

Test 7, RCL 50

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