View Issue Details
| ID | Project | Category | View Status | Date Submitted | Last Update |
|---|---|---|---|---|---|
| 0000167 | ascend | compiler | public | 2005-12-14 09:25 | 2011-02-28 16:10 |
| Reporter | john | ||||
| Assigned To | ben | ||||
| Priority | normal | Severity | major | Reproducibility | always |
| Status | assigned | Resolution | open | ||
| Product Version | |||||
| Target Version | 1.0 | Fixed in Version | |||
| Summary | 0000167: logical expressions forced to write in simple form | ||||
| Description | An aside, it also appears that I can't use an expression like issat IS_A boolean_var; issat_expr: issat == SATISFIED(issat1_test) OR SATISFIED(issat2_test); Instead, it seems that I must use issat1 IS_A boolean_var; issat1_expr: issat1 == SATISFIED(issat1_test); issat2 IS_A boolean_var; issat2_expr: issat1 == SATISFIED(issat2_test); issat IS_A boolear_var; issat_expr: issat == issat1 OR issat2; Why so? | ||||
| Tags | No tags attached. | ||||
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This design is a lesson learned from boolean programming. writing compound constraints of the sort you exhibit leaves a model full of implicit boolean variables. This is then extremely difficult to feed to solvers in general and in particular the typical solver of mixed algebraic/logical models which splits logic and nonlinearity into separate sub-solvers and iterates between. |
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Hi Ben So is this a limitation of the solver, or the compiler? If I can't use the above syntax, then ASCEND should be warning me, right? JP |
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To my knowledge, we have no boolean logic solver for multivariable equations, but the explicit form is solvable as a series of singletons. |
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The resolution to this is probably to have some more sophisticated checks in the LRSlv 'slv_eligible' function. |
| Date Modified | Username | Field | Change |
|---|---|---|---|
| 2005-12-14 09:25 | john | New Issue | |
| 2006-01-24 14:20 | john | Status | new => assigned |
| 2006-01-24 14:20 | john | Assigned To | => ben |
| 2006-02-07 13:17 | john | Target release | => 1.0 |
| 2006-02-07 13:22 | john | Target release | 1.0 => 0.9.6 |
| 2006-02-25 09:36 | john | Severity | minor => major |
| 2006-06-05 16:50 | ben | Note Added: 0000361 | |
| 2006-06-15 10:08 | john | Note Added: 0000373 | |
| 2009-05-14 07:03 | ben | Note Added: 0000528 | |
| 2010-03-23 18:26 | john | Target Version | => 0.9.8 |
| 2011-02-22 17:37 | john | Note Added: 0000676 | |
| 2011-02-28 16:10 | john | Target Version | 0.9.8 => 1.0 |
