Example of "Result Decimal Position" Precision Rules

The following examples illustrate the "Result Decimal Position" precision rules:

Figure 1. Examples of Precision Rules
 *..1....+....2....+....3....+....4....+....5....+....6....+....7...+....
* This example shows the precision of the intermediate values
* using the two precision rules.

D p1              s             26p 2
D p2              s             26p 2
D p3              s             26p 2
D p4              s             26p 9
D s1              s             26s 2
D s2              s             26s 2
D i1              s             10i 0
D f1              s              8f
D proc            pr            15p 3
D   parm1                       20p 5 value

* In the following examples, for each sub-expression,
* two precisions are shown.  First, the natural precision,
* and then the adjusted precision.

 /FREE    
      // Example 1:
    eval    p1 = p1 * p2 * p3;  
      // p1*p2        -> P(52,4); P(52,4)
      // p1*p2*p3     -> P(78,6); P(63,0) (decimal positions are truncated)
    eval(r) p1 = p1 * p2 * p3;    
      // p1*p2        -> P(52,4); P(52,4)
      // p1*p2*p3     -> P(78,6); P(63,2) (decimal positions do not drop
      //               below target decimal positions)
    eval(rh)p1 = p1 * p2 * p3;    
      // p1*p2        -> P(52,4); P(52,5)
      // p1*p2*p3     -> P(78,6); P(63,3) (decimal positions do not drop
      //               below target decimals + 1)
      // Example 2:
    eval    p4 = p1 * p2 * proc (s1*s2*p4);    
      // p1*p2        -> P(52,4); P(52,4)
      // s1*s2        -> P(52,4); P(52,4)
      // s1*s2*p4     -> P(78,13); P(63,0) (decimal positions are truncated)
      // p1*p2*proc() -> P(67,7); P(63,3)  (decimal positions are truncated)
    eval(r) p4 = p1 * p2 * proc (s1*s2*p4);    
      // p1*p2        -> P(52,4); P(52,4)
      // s1*s2        -> P(52,4); P(52,4)
      // s1*s2*p4     -> P(78,13); P(63,5)
      // p1*p2*proc() -> P(67,7); P(63,7)  (we keep all decimals since we are
      //                already below target decimals)
/END-FREE