System Variable IC: Difference between revisions
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Sudleyplace (talk | contribs) (New page: =Indeterminate Control= <table border="1" cellpadding="5" cellspacing="0" rules="none" summary=""> <tr> <td> <table border="0" cellpadding="5" cellspacing="0" summary=""> <tr> ...) |
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<td>sets all of the values of the Indeterminate Control Vector.</td> | <td>sets all of the values of the Indeterminate Control Vector to <apll>R</apll>.</td> | ||
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<td>sets the | <td>sets the value(s) of the Indeterminate Control Vector indexed by <apll>L</apll> to <apll>R</apll>.</td> | ||
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Revision as of 11:16, 18 May 2008
Indeterminate Control
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| Z is an integer vector whose elements each control a separate aspect of how indeterminates are handled by the system. |
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This experimental feature attempts to collect together in one place control of various indeterminate calculations such as 0÷0 and friends. The values of this multi-element vector each control a different calculation. In particular,
| ⎕IC Index (origin-0) |
Indeterminate Calculation |
Default Result |
|---|---|---|
| 0 | ÷0 | ∞ |
| 1 | ⍟0 | ¯∞ |
| 2 | !N for integer N < 0 | DOMAIN ERROR |
| 3 | 0×∞ and ∞×0 | DOMAIN ERROR |
| 4 | 0ׯ∞ and ¯∞×0 | DOMAIN ERROR |
| 5 | 0÷0 | 1 |
| 6 | ∞÷∞ (same sign) | DOMAIN ERROR |
| 7 | ∞÷∞ (different sign) | DOMAIN ERROR |
| 8 | 0*0 | 1 |
| 9 | 0⍟0 | DOMAIN ERROR |
| 10 | 0⍟1 | DOMAIN ERROR |
| 11 | 1⍟0 | DOMAIN ERROR |
| 12 | 1⍟1 | 1 |
The values in each element of ⎕IC control the result of the calculation as follows:
| ⎕IC Value | Result |
|---|---|
| 0 | 0 |
| 1 | 1 |
| 2 | DOMAIN ERROR |
| 3 | ∞ |
| 4 | ¯∞ |
For example,
⎕IO←0
⎕IC
3 4 2 2 2 1 2 2 1 2 2 2 1
0÷0
1
⎕IC[5]←2
0÷0
DOMAIN ERROR
0÷0
∧
⎕IC←⍬
⎕IC
3 4 2 2 2 1 2 2 1 2 2 2 1
