APPENDIX B 

 DESCRIPTION OF DIGITAL COMPUTER PROGRAM AND FLOW CHARTS 



A digital computer program has been devised to solve for the problem just discussed. 

 The coding was done in FORTRAN. An index of FORTRAN symbols used (Figure 4b), a 

 listing of the FORTRAN statements (Figure 4a), and flow charts (Figure 5) are provided to 

 explain the program. Items will be discussed in the order they appear in the listing. 



INPUT 



Provision has been made for both card or tape input, under control of sense switch 5. 

 The input tape has been designated 5. The designation is immediately read out after it is 

 read; see Figure 5b. 



SCALE RENUMBER 



SCALE refers to modifying input data to allow the machine to work with numbers of 

 the same units if the user wants to use a certain mixed set of units for the data. Every node 

 and plate is assigned a number by the person who prepares the input cards. It is not required 

 that they be in sequential order. (This is useful because if one wants to see the effect of 

 removing a plate, the card in question can be removed, and the others do not have to be re- 

 numbered; the count NP must be changed of course.) A dictionary (called NRANK) is made 

 such that if NRANK(5) = 3, then the node that the usercalls 5 is in the third location. The 

 nodes will be referred to (in the program) by the order in which they appear in memory (the 

 order of input), so that references (NH and NT) of the plates to nodes must be changed. 

 Each NH and NT is found in the dictionary and replaced by that number. If a number is speci- 

 fied on one of the plate cards for NH or NT and no node of that number had been given, an 

 output statement to that effect will be made, and after checking the rest of the cards to see 

 if any more errors were made, the computer will immediately return to try the set of data for 

 the next section, if any. 



EXTRACT KEY 



No test was made here to see that the value is allowable. The first and third digits 

 must be 1 or 2, the second digit may be 1, 2, 3, or 4. Other values will probably result in 

 the computer becoming lost. See Figure 4b for the meaning of these symbols. 



The arithmetic statements are quite straightforward and should cause no difficulty. 

 No provision is made to branch an overflow. 



