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ID  Project  Category  View Status  Date Submitted  Last Update 

0000943  MetaPost  feature request  public  20150727 20:24  20150804 18:02 
Reporter  toby  Assigned To  
Priority  normal  Severity  tweak  Reproducibility  always 
Status  new  Resolution  open  
Product Version  1.890  
Summary  0000943: in plain.mp, eps and infinity constants could be better defined for new number systems  
Description  Currently plain.mp has these three definitions... eps := .00049; % this is a pretty small positive number epsilon := 1/256/256; % but this is the smallest infinity := 4095.99998; % and this is the largest it would be nice if the decimal constants could be replaced by expressions that could be evaluated at full precision by the new number systems. Like this: eps := 1/2048; % this is a pretty small positive number epsilon := 1/256/256; % but this is the smallest infinity := 64*64epsilon; % and this is the largest This would make no difference when using the default scaled numbers, but would make the constants more consistent when using higher precision number systems. In particular it would make "infinity+epsilon=4096" true which ever number system is used.  
Tags  No tags attached.  

While we are about it, it would also be nice to replace the units of measure definitions with equivalent relations that are more accurate with the higher precision numeric engines. For example replace the existing lines in "plain.mp" mm=2.83464; pt=0.99626; dd=1.06601; bp:=1; cm=28.34645; pc=11.95517; cc=12.79213; in:=72; with these equivalent lines, which give full precision regardless of engine 72 = 1 in; 800 = 803 pt; 360 = 127 mm; 3600 = 127 cm; 1 pc = 12 pt; 1 cc = 12 dd; 1157 dd = 1238 pt; bp = 1; 

Hm, I tend to consider plain.mp kind of frozen  I think it could be still in use for TAOCP, for example. Better to think to a newplain.mp instead, or something similar. 
Date Modified  Username  Field  Change 

20150727 20:24  toby  New Issue  
20150804 17:16  toby  Note Added: 0001393  
20150804 18:02  luigi scarso  Note Added: 0001394 