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UNITED STATES NATIONAL MUSEUM BULLETIN 2 85 



Error Messages in DASAN 



Only one error message has been written into DASAN, 

 which reads, ANOMALOUS VALUE IN DATA. This 

 statement will appear and the job will be terminated for 

 any of the following reasons: 



1. Control cards contain negative values where these 

 are not allowed. 



2. A zero on a card in the data deck has been used as 

 a signal for division by a constant, whereas only a + 1 or a 

 — 1 is permitted. 



3. A variable which is to be converted to a logarithm 

 is negative. 



VPLOT: Description of Program 



The variable plotting program (VPLOT) provides for very 

 rapid plotting of bivariate scatter diagrams and the con- 

 struction of reduced major axes or regression lines. The 

 univariate output array of DASAN (Figure 1 ) , or any array 

 in which columns represent variables (measurements) and 

 rows represent specimens, may serve as the input data array. 

 Within VPLOT, this input array is altered and /or expanded 

 to form an internal data array. Alterations consist of loga- 

 rithmic (base 10) transformations of any of the input vari- 

 ables, with the logs replacing the original values. Alterna- 

 tively, the logs may be entered in new columns of variables, 

 thereby preserving the original values. An alteration of the 

 input array is desirable if only the logs are to be plotted and 

 not the original values. On the other hand, expanding the 

 input array by entering the logs in new columns allows both 

 the original data and the logs to be plotted. 



The main routine of VPLOT is concerned with input, 

 with the alteration and expansion of the input array, and 

 with output. The actual plotting of each bivariate scatter 

 diagram is carried out by the subroutine, APLOT, which 

 employs both Boolean algebra and FAP. This subroutine 

 accepts and plots the values in two columns of the internal 

 data array at a time according to column indentification 

 numbers specified on control cards. 



Listed below are the main steps followed by the program: 



VPLOT (main) 



1. Control cards, variable format, and data are read in. 



2. The value of each input variable (except for the first, 

 which should be a specimen indentification number) is 

 compared to a specified minimum value. If below this value, 

 the variable is replaced by the specified minimum. 



3. The value of each input variable is compared to a 

 specified maximum value. If greater than this value, the 

 variable is replaced by the specified maximum. 



4. Columns of variables, specified on control cards, are 

 replaced by their logarithms (base 10). 



5. The logarithms of specified columns of variables 

 are computed and entered as new columns of data. 



6. Two variables, designated as x and y on control cards, 

 are entered as arguments in a call to Subroutine APLOT. 



Subroutine APLOT 



7. One bivariate scatter diagrams is computed, and 

 control is returned to the main program. 



VPLOT (main) 



8. The scatter diagram computed by APLOT is 

 printed. 



9. If more diagrams remain to be plotted, Steps 6 

 through 8 are repeated for each plot. 



10. If more data decks remain in the run, control returns 

 to Step 1 with the reading in of new control cards and data. 

 Otherwise, the job is completed. 



Computation Time. — The sample problem described be- 

 low ( 12 specimens, 36 input variables, and 43 plots) required 

 only 50 seconds on the IBM 7094. Increasing the number of 

 specimens does not add greatly to the computation time. 



Core Space. — The space occupied by VPLOT is not large, 

 but because there are difficulties in plotting points consisting 

 of three digits rather than two, 99 must remain the upper 

 limit of the number of specimens which can be run at a time. 



