The CLP Procedure
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Overview
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Getting Started
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Syntax
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Details
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ExamplesLogic-Based PuzzlesAlphabet Blocks ProblemWork-Shift Scheduling ProblemA Nonlinear Optimization ProblemCar Painting ProblemScene Allocation ProblemCar Sequencing ProblemRound-Robin ProblemResource-Constrained Scheduling with Nonstandard Temporal ConstraintsScheduling with Alternate Resources10×10 Job Shop Scheduling ProblemScheduling a Major Basketball ConferenceBalanced Incomplete Block DesignProgressive Party ProblemStatement and Option Cross-Reference Table
- References
ALLDIFF Statement
ALLDIFF (variable_list-1) <…(variable_list-n)> ;
ALLDIFFERENT (variable_list-1) <…(variable_list-n)> ;
The ALLDIFF statement can have multiple specifications. Each specification defines a unique global constraint on a set of variables, requiring all of them to be different from each other. A global constraint is equivalent to a conjunction of elementary constraints.
For example, the statements
var (X1-X3) A B; alldiff (X1-X3) (A B);
are equivalent to
![\[ \begin{array}{rcl} X1 & \ne & X2 \mr {~ ~ AND}\\ X2 & \ne & X3 \mr {~ ~ AND}\\ X1 & \ne & X3 \mr {~ ~ AND}\\ A & \ne & B \end{array} \]](images/orcpug_clp0027.png) |
If the variable list is empty, the ALLDIFF constraint applies to all the variables declared in any VARIABLE statement.