Scallop

https://www.scallop-lang.org/doc/
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### Scallopy ScallopContext Setup

Source: https://www.scallop-lang.org/doc/print

Provides a concise example of setting up and using a 'ScallopContext' in Python. It covers adding relations, facts, defining a rule for path computation, and executing the program.

```python
import scallopy

# Creating a new context
ctx = scallopy.ScallopContext()

# Add relation of `edge`
ctx.add_relation("edge", (int, int))
ctx.add_facts("edge", [(0, 1), (1, 2)])

# Add rule of `path`
ctx.add_rule("path(a, c) = edge(a, c) or path(a, b) and edge(b, c)")

# Run!
ctx.run()
```

--------------------------------

### Scallop Context Setup and Execution

Source: https://www.scallop-lang.org/doc/scallopy/context

Demonstrates how to initialize a ScallopContext, define relations, add facts, declare rules, run the computation, and retrieve results. This is a fundamental example for interacting with the Scallop engine.

```Python
import scallopy

# Creating a new context
ctx = scallopy.ScallopContext()

# Add relation of `edge`
ctx.add_relation("edge", (int, int))
ctx.add_facts("edge", [(0, 1), (1, 2)])

# Add rule of `path`
ctx.add_rule("path(a, c) = edge(a, c) or path(a, b) and edge(b, c)")

# Run!
ctx.run()

# Check the result!
print(list(ctx.relation("path"))) # [(0, 1), (0, 2), (1, 2)]

```

--------------------------------

### Install Scallop Interpreter (scli)

Source: https://www.scallop-lang.org/doc/installation

Installs the Scallop interpreter, named 'scli', using the provided Makefile command. This tool is used to test and run Scallop programs.

```shell
$ make install-scli
```

--------------------------------

### Scallop Pretty-Printing Execution Example

Source: https://www.scallop-lang.org/doc/language/adt_and_entity

An example demonstrating how to define an expression and query the pretty-printing relation. It shows the input expression and the expected output format.

```scallop
const MY_EXPR = Sub(Add(Int(3), Int(5)), Int(1))
query to_string(MY_EXPR, s)
```

--------------------------------

### Scallop Query Example

Source: https://www.scallop-lang.org/doc/language/query

Demonstrates how to define relations and rules in Scallop, and how to query specific relations to retrieve computed results. This example shows counting students enrolled in CS classes.

```Scallop
rel classes = {0, 1, 2}

rel enroll = {
  ("tom", "CS"), ("jenny", "Math"), // Class 0
  ("alice", "CS"), ("bob", "CS"), // Class 1
  ("jerry", "Math"), ("john", "Math"), // Class 2
}

rel num_enroll_cs(n) = n := count(s: enroll(s, "CS"))

query num_enroll_cs
```

--------------------------------

### Install Scallop CLI

Source: https://www.scallop-lang.org/doc/print

Command to install the Scallop interpreter (scli) using the make build system. This command is typically run from the Scallop source directory.

```Shell
$ make install-scli
```

--------------------------------

### Scallop Example Usage and Query

Source: https://www.scallop-lang.org/doc/print

Demonstrates how to use the defined Scallop relations by providing input regex and string, and then querying the `matches` relation to check for a match.

```Scallop
rel input_regex(A_STAR_B)
rel input_string("aaaab")
query matches // {()}
```

--------------------------------

### Scallop Fixed-point Iteration Example

Source: https://www.scallop-lang.org/doc/print

Demonstrates the execution of Scallop rules through fixed-point iteration. It shows how relations are updated iteratively until no new facts are derived, illustrating the convergence process.

```Scallop
rel edge = {(0, 1), (1, 2), (2, 3)}
rel path(a, b) = edge(a, b)                 // rule 1
rel path(a, c) = path(a, b) and edge(b, c)  // rule 2

Iter 0: path = {}
Iter 1: path = {(0, 1), (1, 2), (2, 3)}
       Δpath = {(0, 1), (1, 2), (2, 3)} // through applying rule 1
Iter 2: path = {(0, 1), (1, 2), (2, 3), (0, 2), (1, 3)}
       Δpath = {(0, 2), (1, 3)}         // through applying rule 2
Iter 3: path = {(0, 1), (1, 2), (2, 3), (0, 2), (1, 3), (0, 3)}
       Δpath = {(0, 3)}                 // through applying rule 2
Iter 4: path = {(0, 1), (1, 2), (2, 3), (0, 2), (1, 3), (0, 3)}
       Δpath = {}
```

--------------------------------

### Scallop: Equality Saturation Setup

Source: https://www.scallop-lang.org/doc/print

Defines the necessary Scallop types for equality saturation: input expressions, equivalence relations, and weight functions.

```scallop
type input_expr(expr: Expr)
type equivalent(expr_1: Expr, expr_2: Expr)
type weight(expr: Expr, w: i32)
type simplest(expr: Expr)

```

--------------------------------

### Scallop Debugging with difftopkproofsdebug

Source: https://www.scallop-lang.org/doc/print

Demonstrates how to use the 'difftopkproofsdebug' provenance in Scallop for debugging proofs. This method requires special handling when adding facts, necessitating the inclusion of a unique 'Fact ID' for each fact, typically starting from 1 and being contiguous. The example shows the structure for probabilistic facts with Fact IDs.

```python
import scallopy
import torch

# Initialize Scallop context with debugging provenance and k value
ctx = scallopy.ScallopContext(provenance="difftopkproofsdebug", k=3)

# Add relations with their Python types
ctx.add_relation("digit_a", int)
ctx.add_relation("digit_b", int)

# Define a rule
ctx.add_rule("sum_2(a + b) = digit_a(a) and digit_b(b)")

# Add facts with special treatment: ( (probability_tensor, fact_id), tuple_data )
# Fact IDs must be distinct and contiguous for debugging.
ctx.add_facts("digit_a", [
  ((torch.tensor(0.1), 1), (0,)), 
  ((torch.tensor(0.9), 2), (1,)) 
])
ctx.add_facts("digit_b", [
  ((torch.tensor(0.9), 3), (1,)), 
  ((torch.tensor(0.1), 4), (2,)) 
])

# Run the computation
ctx.run()

# Retrieve the result relation
result = ctx.relation("sum_2")

# Example of the required fact structure for non-probabilistic facts (tag=None)
# ctx.add_facts("SOME_RELATION", [
#   ( ( None, 5 ) , (    0,   ) ) # Non-probabilistic fact with Fact ID 5
# ])

```

--------------------------------

### Scallop Graph Transitive Closure Example

Source: https://www.scallop-lang.org/doc/print

Provides an example of graph data and the resulting transitive closure computed by Scallop rules. It shows how edges and paths are derived.

```Scallop
rel edge = {(0, 1), (1, 2)}
```

--------------------------------

### Scallopy Python API Usage Example

Source: https://www.scallop-lang.org/doc/scallopy/getting_started

Demonstrates basic interaction with the Scallop Python API. It shows how to create a context, define relations, add facts, write rules, execute the program, and retrieve results.

```Python
import scallopy

ctx = scallopy.Context()

ctx.add_relation("edge", (int, int))
ctx.add_facts("edge", [(1, 2), (2, 3)])

ctx.add_rule("path(a, c) = edge(a, c) or path(a, b) and edge(b, c)")

ctx.run()

print(list(ctx.relation("path"))) # [(1, 2), (1, 3), (2, 3)]

```

--------------------------------

### Scallop: Example Edge Relation

Source: https://www.scallop-lang.org/doc/language/recursion

Provides a concrete example of facts for the `edge` relation, used to illustrate the pathfinding computation. This set of facts defines the initial graph structure.

```scallop
rel edge = {(0, 1), (1, 2)}
```

--------------------------------

### Scallop: Define Expression Type and Example

Source: https://www.scallop-lang.org/doc/print

Defines a symbolic expression type using Scallop's type system and provides an example expression for demonstration.

```scallop
type Expr = Const(i32) | Var(String) | Add(Expr, Expr)

const MY_EXPR = Add(Add(Const(-3), Var("a")), Const(3)) // (-3 + a) + 3

```

--------------------------------

### Scallopy Basic Context Example

Source: https://www.scallop-lang.org/doc/print

Illustrates the fundamental usage of the 'scallopy' Python binding. It shows how to create a context, add relations and facts, define a rule, run the computation, and retrieve results.

```python
import scallopy

ctx = scallopy.Context()

ctx.add_relation("edge", (int, int))
ctx.add_facts("edge", [(1, 2), (2, 3)])

ctx.add_rule("path(a, c) = edge(a, c) or path(a, b) and edge(b, c)")

ctx.run()

print(list(ctx.relation("path"))) # [(1, 2), (1, 3), (2, 3)]
```

--------------------------------

### Scallop Logic Programming: Fibonacci Example

Source: https://www.scallop-lang.org/doc/introduction

Demonstrates basic Scallop syntax for defining types, relations, and recursive rules to compute Fibonacci numbers. Includes a query to retrieve results.

```Scallop
type fib(bound x: i32, y: i32)
rel fib = {(0, 1), (1, 1)}
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2) and x > 1
query fib(10, y)
```

--------------------------------

### Scallop Logic Programming: Fibonacci Example

Source: https://www.scallop-lang.org/doc/index

Demonstrates basic Scallop syntax for defining types, relations, and recursive rules to compute Fibonacci numbers. Includes a query to retrieve results.

```Scallop
type fib(bound x: i32, y: i32)
rel fib = {(0, 1), (1, 1)}
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2) and x > 1
query fib(10, y)
```

--------------------------------

### Scallop Expression Example and String Conversion

Source: https://www.scallop-lang.org/doc/language/adt_and_entity

Demonstrates defining a Scallop expression and a `to_string` relation for its visualization. Includes a query to show the string representation.

```scallop
const MY_EXPR = Add(Add(Const(-3), Var("a")), Const(3)) // (-3 + a) + 3

rel to_string(p, i as String) = case p is Const(i)
rel to_string(p, v)           = case p is Var(v)
rel to_string(p, $format("({} + {})", s1, s2)) =
  case p is Add(p1, p2) and to_string(p1, s1) and to_string(p2, s2)

query to_string(MY_EXPR, s) // s = "((-3 + a) + 3)"

```

--------------------------------

### Scallop Neuro-Symbolic Example

Source: https://www.scallop-lang.org/doc/print

Demonstrates Scallop's ability to combine knowledge base facts, rules, probabilistic facts, and aggregations for relational reasoning.

```Scallop
// Knowledge base facts
rel is_a("giraffe", "mammal")
rel is_a("tiger", "mammal")
rel is_a("mammal", "animal")

// Knowledge base rules
rel name(a, b) :- name(a, c), is_a(c, b)

// Recognized from an image, maybe probabilistic
rel name = {
  0.3::(1, "giraffe"),
  0.7::(1, "tiger"),
  0.9::(2, "giraffe"),
  0.1::(2, "tiger"),
}

// Count the animals
rel num_animals(n) :- n = count(o: name(o, "animal"))

```

--------------------------------

### Scallop Interpreter Output for Probabilistic Query

Source: https://www.scallop-lang.org/doc/print

Example output from the Scallop interpreter (scli) showing the derived probability for a queried relation, demonstrating the result of probabilistic reasoning.

```Shell
> scli alarm.scl
alarm: {0.224::()}
```

--------------------------------

### Instantiate Linked List

Source: https://www.scallop-lang.org/doc/print

Creates an instance of the `List` ADT to represent a sequence of integers. This example shows how to define constants for data structures and provides a common representation for lists.

```Scallop
const MY_LIST = Cons(1, Cons(2, Cons(3, Nil()))) // [1, 2, 3]
```

--------------------------------

### Basic Scallop Fact Addition and Execution

Source: https://www.scallop-lang.org/doc/scallopy/debug_proofs

Demonstrates the initial setup for adding facts to a Scallop context and running a relation. This includes defining probabilistic facts with associated fact IDs.

```python
ctx.add_facts("digit_a", [((torch.tensor(0.1), 1), (1,)), ((torch.tensor(0.9), 2), (2,))])
ctx.add_facts("digit_b", [((torch.tensor(0.9), 3), (1,)), ((torch.tensor(0.1), 4), (2,))])

ctx.run()
result = ctx.relation("sum_2")
```

--------------------------------

### Scallop Expressions Bounding Variables

Source: https://www.scallop-lang.org/doc/print

Shows an example where an expression `b + 1` in the body of a rule is used to derive the variable `b` in the head, effectively grounding it.

```Scallop
rel output_relation(a, b) = input_relation(a, b + 1)
```

--------------------------------

### Execute Scallop Program and Show Output

Source: https://www.scallop-lang.org/doc/probabilistic/provenance

This snippet shows the command-line execution of a Scallop program file (`alarm.scl`) using the `scli` interpreter and the resulting output, which includes the inferred probability for the queried fact 'alarm'.

```shell
> scli alarm.scl
alarm: {0.224::()}
```

--------------------------------

### Run Scallop Program with CLI

Source: https://www.scallop-lang.org/doc/print

Command to execute a Scallop Datalog program file using the installed scli interpreter. It takes the path to the Scallop source file as an argument.

```Shell
$ scli examples/datalog/edge_path.scl
```

--------------------------------

### Scallop Regex Matching Relations Setup

Source: https://www.scallop-lang.org/doc/language/adt_and_entity

Sets up the necessary relations for checking if a given regular expression matches a string. It defines input relations for the regex and string, and relations for substring matching.

```scallop
type input_regex(r: Regex)
type input_string(s: String)
type matches_substr(r: Regex, begin: usize, end: usize)
type matches()
```

--------------------------------

### Scallop: Fixed-Point Iteration Example

Source: https://www.scallop-lang.org/doc/language/recursion

Illustrates the step-by-step execution of a Scallop program with recursion using fixed-point iteration. It shows how the `path` relation is populated over multiple iterations based on the `edge` relation and recursive rules.

```scallop
rel edge = {(0, 1), (1, 2), (2, 3)}
rel path(a, b) = edge(a, b)                 // rule 1
rel path(a, c) = path(a, b) and edge(b, c)  // rule 2
```

--------------------------------

### Scallop Infinite Relation Fibonacci Example

Source: https://www.scallop-lang.org/doc/print

Shows how Scallop can define infinite relations using recursion and value creation, such as a Fibonacci sequence. It also demonstrates how to bound such relations to ensure termination.

```Scallop
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2)

// Bounded version:
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2) and x <= 10
```

--------------------------------

### Scallop Data Definition and Counting Enrollments

Source: https://www.scallop-lang.org/doc/print

Defines relations for classes and student enrollments, and a rule to count the number of students enrolled in 'CS' courses. This sets up data for query examples.

```Scallop
// There are three classes
rel classes = {0, 1, 2}

// Each student is enrolled in a course (Math or CS)
rel enroll = {
  ("tom", "CS"), ("jenny", "Math"), // Class 0
  ("alice", "CS"), ("bob", "CS"), // Class 1
  ("jerry", "Math"), ("john", "Math"), // Class 2
}

// Count how many student enrolls in CS course
rel num_enroll_cs(n) = n := count(s: enroll(s, "CS"))
```

--------------------------------

### Scallop Neurosymbolic Programming Example

Source: https://www.scallop-lang.org/doc/introduction

Demonstrates Scallop's capabilities by combining knowledge base facts, rules, and probabilistic facts recognized from images. It shows how to define relations, rules, probabilistic assignments, and perform aggregations.

```Scallop
// Knowledge base facts
rel is_a("giraffe", "mammal")
rel is_a("tiger", "mammal")
rel is_a("mammal", "animal")

// Knowledge base rules
rel name(a, b) :- name(a, c), is_a(c, b)

// Recognized from an image, maybe probabilistic
rel name = {
  0.3::(1, "giraffe"),
  0.7::(1, "tiger"),
  0.9::(2, "giraffe"),
  0.1::(2, "tiger"),
}

// Count the animals
rel num_animals(n) :- n = count(o: name(o, "animal"))

```

--------------------------------

### Scallop Neurosymbolic Programming Example

Source: https://www.scallop-lang.org/doc/index

Demonstrates Scallop's capabilities by combining knowledge base facts, rules, and probabilistic facts recognized from images. It shows how to define relations, rules, probabilistic assignments, and perform aggregations.

```Scallop
// Knowledge base facts
rel is_a("giraffe", "mammal")
rel is_a("tiger", "mammal")
rel is_a("mammal", "animal")

// Knowledge base rules
rel name(a, b) :- name(a, c), is_a(c, b)

// Recognized from an image, maybe probabilistic
rel name = {
  0.3::(1, "giraffe"),
  0.7::(1, "tiger"),
  0.9::(2, "giraffe"),
  0.1::(2, "tiger"),
}

// Count the animals
rel num_animals(n) :- n = count(o: name(o, "animal"))

```

--------------------------------

### Scallop Probabilistic Aggregation Example (Count)

Source: https://www.scallop-lang.org/doc/print

Shows how aggregators like 'count' can be used with probabilistic facts, potentially employing multi-world semantics to aggregate results across different probability distributions.

```Scallop
type OBJ = OBJ_A | OBJ_B
rel size = {0.8::(OBJ_A, "big"); 0.2::(OBJ_A, "small")} // obj A is very likely big
rel size = {0.1::(OBJ_B, "big"); 0.9::(OBJ_B, "small")} // obj B is very likely small
```

--------------------------------

### Scallop Dependency Graph Example

Source: https://www.scallop-lang.org/doc/print

Illustrates the dependency graph for the `has_no_child` rule, showing positive and negative dependencies between predicates. This helps visualize how rules relate to each other in terms of data flow and negation.

```Scallop
person <--pos-- has_no_child --neg--> father
                      |
                      +-----neg-----> mother
```

--------------------------------

### Scallop Atomic Query Example

Source: https://www.scallop-lang.org/doc/language/query

Illustrates writing an atomic query in Scallop to retrieve a specific value from a relation, such as finding the 8th Fibonacci number. It shows how to specify arguments in the query.

```Scallop
type fib(x: i32, y: i32)
rel fib = {(0, 1), (1, 1)}
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2) and x <= 10
query fib(8, y)
```

--------------------------------

### Scallop: Create and Use Entities (Lists)

Source: https://www.scallop-lang.org/doc/language/adt_and_entity

Explains how to create constants, referred to as Entities, using the `const` keyword and ADT definitions. It provides an example of defining a list ADT and creating a list entity.

```scallop
type List = Cons(i32, List) | Nil()
const MY_LIST = Cons(1, Cons(2, Cons(3, Nil()))) // [1, 2, 3]
```

--------------------------------

### Scallop Sampling with Probability Example

Source: https://www.scallop-lang.org/doc/probabilistic/sampling

Demonstrates the use of the 'top' sampler in Scallop, which allows retrieving top-ranked facts based on probability. Samplers share syntax with aggregators and can be used with or without probabilistic provenances.

```scallop
rel symbols = {0.9::"+", 0.05::"-", 0.02::"3"}
rel top_symbol(s) = s := top<1>(s: symbols(s)) // 0.9::top_symbol("+")
```

--------------------------------

### Scallop Logic Programming: Fibonacci Example

Source: https://www.scallop-lang.org/doc/print

Defines a recursive Fibonacci relation using Scallop's Datalog-like syntax. It includes type definitions, base cases, recursive rules, and a query.

```Scallop
type fib(bound x: i32, y: i32)
rel fib = {(0, 1), (1, 1)}
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2) and x > 1
query fib(10, y)
```

--------------------------------

### Scallop: Use Entities in Relations and Queries

Source: https://www.scallop-lang.org/doc/language/adt_and_entity

Shows how to incorporate constant entities into facts within relations and query them. It explains that identical entities receive the same unique identifier, demonstrated with list examples.

```scallop
rel target(MY_LIST)
query target

// Expected output:
target: {(entity(0xff08d5d60a201f17))}

const MY_LIST_1 = Cons(1, Nil()),
      MY_LIST_2 = Cons(1, Nil()),
      MY_LIST_3 = Cons(2, Nil())

rel lists = {
  (1, MY_LIST_1),
  (2, MY_LIST_2),
  (3, MY_LIST_3),
}

query lists
// Expected output:
// lists: {
//   (1, entity(0x678defa0a65c83ab)), // Notice that the entity 1 and 2 are the same
//   (2, entity(0x678defa0a65c83ab)),
//   (3, entity(0x3734567c3d9f8d3f)), // This one is different than above
// }
```

--------------------------------

### Define Rule and Query Alarm

Source: https://www.scallop-lang.org/doc/probabilistic/provenance

Declares a rule where an `alarm()` occurs if either `earthquake()` or `burglary()` is true. It then queries the derived `alarm()` fact, showcasing rule definition and probabilistic inference in Scallop.

```scallop
rel alarm() = earthquake() or burglary()
query alarm
```

--------------------------------

### Scallop: Using Conjunction (and, /\) in Rule Definitions

Source: https://www.scallop-lang.org/doc/print

Demonstrates how to combine relations using the `and` operator or its symbolic equivalent `/` in Scallop rule bodies. This is crucial for joining relations on common variables, as shown in the `grandmother` example.

```scallop
rel grandmother(a, c) = mother(a, b) and father(b, c)
// or
rel grandmother(a, c) = mother(a, b) /\ father(b, c)
```

--------------------------------

### Scallop: Infinite Relation Example (Fibonacci)

Source: https://www.scallop-lang.org/doc/language/recursion

Shows how Scallop can define infinite relations, such as a Fibonacci sequence generator, by allowing value creation through arithmetic operations in recursive rules. This can lead to non-terminating fixed-point iterations.

```scallop
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2)
```

--------------------------------

### Create and Invoke Scallopy Module with PyTorch

Source: https://www.scallop-lang.org/doc/scallopy/getting_started

This example demonstrates defining a Scallopy `Module` with a logical program and input/output mappings. It shows how to invoke this module using PyTorch tensors, facilitating batched execution and integration into machine learning workflows.

```python
import scallopy
import torch

# Creating a module for execution
my_sum2 = scallopy.Module(
  program="""
    type digit_1(a: i32), digit_2(b: i32)
    rel sum_2(a + b) = digit_1(a) and digit_2(b)
  """,
  input_mappings={"digit_1": range(10), "digit_2": range(10)},
  output_mappings={"sum_2": range(19)},
  provenance="difftopkproofs")

# Invoking the module with torch tensors. `result` is a tensor of 16 x 19
result = my_sum2(
  digit_1=torch.softmax(torch.randn(16, 10), dim=0),
  digit_2=torch.softmax(torch.randn(16, 10), dim=0))

```

--------------------------------

### Scallop Rule Definition Example

Source: https://www.scallop-lang.org/doc/language/rules

Demonstrates the definition of relations and rules in Scallop. It shows how to declare facts for an 'edge' relation and define a 'path' relation based on the 'edge' relation, illustrating a basic rule structure.

```Scallop
rel edge = {(0, 1), (1, 2)}
rel path(a, b) = edge(a, b) // (0, 1), (1, 2)

```

--------------------------------

### Instantiate Binary Tree

Source: https://www.scallop-lang.org/doc/print

Demonstrates creating an instance of the `Tree` ADT to represent a balanced binary search tree. This shows how to construct complex data structures using the defined ADT.

```Scallop
//         3
//      /     \
//    1         5
//  /   \     /   \
// 0     2   4     6
const MY_TREE =
  Node(3,
    Node(1,
      Node(0, Nil(), Nil()),
      Node(2, Nil(), Nil()),
    ),
    Node(5,
      Node(4, Nil(), Nil()),
      Node(6, Nil(), Nil()),
    )
  )
```

--------------------------------

### Scallop: Unsigned Integer Type Error Example

Source: https://www.scallop-lang.org/doc/language/value_type

Illustrates a type inference error in Scallop when assigning negative numbers to unsigned integer types. The example shows the `sclrepl` output and the specific error message.

```scallop
scl> type my_edge(usize, usize)
scl> rel my_edge = {(-1, -5), (0, 3)}
[Error] cannot unify types `usize` and `signed integer`, where the first is declared here
  REPL:0 | type my_edge(usize, usize)
         |              ^^^^^
and the second is declared here
  REPL:1 | rel my_edge = {(-1, -5), (0, 3)}
         |                 ^^
```

--------------------------------

### Initialize ScallopContext with Provenance

Source: https://www.scallop-lang.org/doc/print

Demonstrates how to create a ScallopContext instance, specifying different provenance types for reasoning. Provenance options include 'unit' for untagged semantics, 'minmaxprob' for probabilistic reasoning, 'diffminmaxprob' for differentiable reasoning, and 'topkproofs' which can accept additional parameters like 'k'.

```python
import scallopy

# Default provenance (unit)
ctx = scallopy.ScallopContext()

# Explicitly specify provenance
ctx = scallopy.ScallopContext(provenance="unit")

# Probabilistic provenance
ctx = scallopy.ScallopContext(provenance="minmaxprob")

# Differentiable provenance
ctx = scallopy.ScallopContext(provenance="diffminmaxprob")

# Top-k proofs provenance with k=5
ctx = scallopy.ScallopContext(provenance="topkproofs", k=5)
```

--------------------------------

### Scallop: Integer Type Inference Error Example

Source: https://www.scallop-lang.org/doc/print

Provides an example of a type inference error in Scallop when attempting to assign a negative number to a variable declared with an unsigned integer type. This highlights Scallop's strict type checking.

```scallop
scl> type my_edge(usize, usize)
scl> rel my_edge = {(-1, -5), (0, 3)}
[Error] cannot unify types `usize` and `signed integer`, where the first is declared here
  REPL:0 | type my_edge(usize, usize)
         |              ^^^^^
and the second is declared here
  REPL:1 | rel my_edge = {(-1, -5), (0, 3)}
         |                 ^^
```

--------------------------------

### Type Inference Failure Example

Source: https://www.scallop-lang.org/doc/print

Demonstrates a type inference failure in Scallop when a relation is assigned conflicting types. The example shows an 'edge' relation with one fact having an integer and another having a string for the same argument position, leading to a unification error.

```scallop
rel edge = {(0, 1), (0, "1")}
```

--------------------------------

### Scallop Negations Example

Source: https://www.scallop-lang.org/doc/language/negation

Demonstrates how to use negation in Scallop rules to define relations based on the absence of certain conditions. It shows how to identify individuals with no children by checking for the absence of them being a father or mother. The example includes the definition of relations, a rule using negation, and the expected output.

```Scallop
rel person = {"bob", "alice", "christine"} // There are three persons of interest
rel father = {("bob", "alice")}            // Bob is Alice's father
rel mother = {("alice", "christine")}      // Alice is Christine's mother

rel has_no_child(n) = person(n) and not father(n, _) and not mother(n, _)

// Expected output:
has_no_child: {("christine",)}

```

--------------------------------

### Debug Top-K Proofs with Scallopy

Source: https://www.scallop-lang.org/doc/scallopy/debug_proofs

Demonstrates how to configure the Scallop context for debugging top-k proofs using the 'difftopkproofsdebug' provenance. It shows adding relations, defining rules, and setting the k-value for debugging.

```python
ctx = scallopy.ScallopContext(provenance="difftopkproofsdebug", k=3)
ctx.add_relation("digit_a", int)
ctx.add_relation("digit_b", int)
ctx.add_rule("sum_2(a + b) = digit_a(a) and digit_b(b)")
```

--------------------------------

### ScallopContext Initialization

Source: https://www.scallop-lang.org/doc/scallopy/context

Demonstrates how to create a ScallopContext with different provenance settings. Provenance options include 'unit' for discrete Datalog, 'minmaxprob' for probabilistic reasoning, 'diffminmaxprob' for differentiable reasoning, and 'topkproofs' which accepts additional parameters like 'k'.

```python
ctx = scallopy.ScallopContext(provenance="unit")
# or
ctx = scallopy.ScallopContext(provenance="minmaxprob")
# or
ctx = scallopy.ScallopContext(provenance="diffminmaxprob")
# or
ctx = scallopy.ScallopContext(provenance="topkproofs", k=5)
```

--------------------------------

### Scallop Ungrounded Variable Example

Source: https://www.scallop-lang.org/doc/print

Illustrates a Scallop rule where a variable `c` in the head is not grounded by any relation or expression in the body, leading to a compilation error.

```Scallop
rel path(a, c) = edge(a, b)
```

--------------------------------

### Scallop Dynamic Entity Creation with Lists

Source: https://www.scallop-lang.org/doc/print

Demonstrates the dynamic creation of new entities using the 'new' keyword in Scallop. This example shows how to prepend an element to an existing list during a deductive process, effectively creating a new list instance.

```scallop
type input_list(List)
rel result_list(new Cons(1, l)) = input_list(l)
```

--------------------------------

### Define Probabilistic Fact Earthquake

Source: https://www.scallop-lang.org/doc/probabilistic/provenance

Defines a probabilistic fact `earthquake()` with a probability of 0.03. This is a core concept in Scallop for representing uncertain events and their likelihoods.

```scallop
rel 0.03::earthquake()
```

--------------------------------

### Decompose List Entity in Rules

Source: https://www.scallop-lang.org/doc/print

Shows how to decompose an entity using the `case`-`is` operator within relation rules. This example computes the length of a list recursively.

```Scallop
type length(list: List, len: i32)
rel length(list, 0)     = case list is Nil()
rel length(list, l + 1) = case list is Cons(_, tl) and length(tl, l)
```

--------------------------------

### Scallop Module Configuration for Debugging

Source: https://www.scallop-lang.org/doc/scallopy/debug_proofs

Shows how to configure a Scallop module for debugging in forward mode. Key parameters include `provenance`, `k`, the Scallop `program`, `output_relation`, and `output_mapping`.

```python
sum_2 = scallopy.Module(
  provenance="difftopkproofsdebug",
  k=3,
  program="""
    type digit_a(a: i32), digit_b(b: i32)
    rel sum_2(a + b) = digit_a(a) and digit_b(b)
  """,
  output_relation="sum_2",
  output_mapping=[2, 3, 4])
```

--------------------------------

### Scallop Atomic Query for Fibonacci

Source: https://www.scallop-lang.org/doc/print

Shows how to perform an atomic query to retrieve a specific value from a recursive relation. This example calculates the 8th Fibonacci number.

```Scallop
type fib(x: i32, y: i32)
rel fib = {(0, 1), (1, 1)}
rel fib(x, y1 + y2) = fib(x - 1, y1) and fib(x - 2, y2) and x <= 10
query fib(8, y) // fib(8, y): {(8, 34)}
```

--------------------------------

### Cloning a Scallop Context

Source: https://www.scallop-lang.org/doc/print

Shows how to create an exact copy of an existing Scallop context. The cloned context includes all program definitions, configurations, and provenance information from the original.

```python
new_ctx = ctx.clone()
```

--------------------------------

### Scallop Ungrounded Variable Example

Source: https://www.scallop-lang.org/doc/language/rules

Illustrates a Scallop rule where a variable `c` in the head is not grounded by any relation or expression in the body, leading to a compilation error.

```Scallop
rel path(a, c) = edge(a, b)
```

--------------------------------

### Define Probabilistic Fact Burglary

Source: https://www.scallop-lang.org/doc/probabilistic/provenance

Defines a probabilistic fact `burglary()` with a probability of 0.20. This demonstrates how to represent another uncertain event and its associated probability in Scallop.

```scallop
rel 0.20::burglary()
```

--------------------------------

### Run Scallop Program with scli

Source: https://www.scallop-lang.org/doc/installation

Executes a Scallop program file using the 'scli' interpreter. This command takes the path to a Scallop source file as an argument.

```shell
$ scli examples/datalog/edge_path.scl
```

--------------------------------

### Scallopy Python Module Initialization

Source: https://www.scallop-lang.org/doc/print

Shows how to initialize a Scallopy module using the Python binding. This involves defining the Scallop program string, input mappings, and output mapping.

```Python
sum_2 = scallopy.Module(
  program="""type digit_1(i32), digit_2(i32)
             rel sum_2(a + b) = digit_1(a) and digit_2(b)""",
  input_mappings={"digit_1": range(10), "digit_2": range(10)},
  output_mapping=("sum_2", range(19)))

```

--------------------------------

### Declaring ADT Entities as Constants

Source: https://www.scallop-lang.org/doc/print

Declares an entity of an ADT as a constant. This example shows how to represent the list `[1, 2, 3]` using the `IntList` ADT definition.

```scallop
const MY_LIST = Cons(1, Cons(2, Cons(3, Nil())))
```

--------------------------------

### Scallop: Specify Fields and Keys

Source: https://www.scallop-lang.org/doc/print

Shows how to use both `keys` and `fields` arguments in Scallop's `@file` annotation to define a type, specifying primary keys and selecting specific columns to load.

```scallop
@file("enrollment.csv", keys=["student_id", "course_id"], fields=["grade"])
type enrollment(student_id: usize, course_id: String, field: String, value: String)
// The following facts will be obtained
//   enrollment(1, "cse100", "grade", "a")
//   enrollment(1, "cse101", "grade", "a")
//   enrollment(2, "cse120", "grade", "b")
```

--------------------------------

### Scallop Basic Atom Definition

Source: https://www.scallop-lang.org/doc/print

Defines a relation `path` based on an `edge` relation. This example shows how variables `a` and `b` in the head are grounded by the `edge` relation in the body.

```Scallop
rel path(a, b) = edge(a, b)
```

--------------------------------

### Scallop: String Declaration

Source: https://www.scallop-lang.org/doc/language/value_type

Shows how to declare and use strings in Scallop. Strings are double-quoted and support escaped characters. An example relation `greeting` is provided.

```scallop
rel greeting = {"Hello World"}
```

--------------------------------

### Scallop Expressions Bounding Variables

Source: https://www.scallop-lang.org/doc/language/rules

Shows an example where an expression `b + 1` in the body of a rule is used to derive the variable `b` in the head, effectively grounding it.

```Scallop
rel output_relation(a, b) = input_relation(a, b + 1)
```

--------------------------------

### Batched Input Data for Debug Mode

Source: https://www.scallop-lang.org/doc/scallopy/debug_proofs

Provides an example of how input data should be structured when using Scallop's debug mode. Data is batched, with each item in the batch representing a data point, and facts within a data point include probabilities and fact IDs.

```python
digit_a = [
  [((torch.tensor(0.1), 1), (1,)), ((torch.tensor(0.9), 2), (2,))], # Datapoint 1
  # ...
]
digit_b = [
  [((torch.tensor(0.9), 3), (1,)), ((torch.tensor(0.1), 4), (2,))], # Datapoint 1
  # ...
]
```

--------------------------------

### Scallop Basic Atom Definition

Source: https://www.scallop-lang.org/doc/language/rules

Defines a relation `path` based on an `edge` relation. This example shows how variables `a` and `b` in the head are grounded by the `edge` relation in the body.

```Scallop
rel path(a, b) = edge(a, b)
```

--------------------------------

### Defining Enum Types

Source: https://www.scallop-lang.org/doc/print

Defines enum types with constant variables like RED, GREEN, BLUE. Values are unsigned integers starting from 0 by default and incrementing sequentially.

```scallop
type Color = RED | GREEN | BLUE
type Action = LEFT | UP | RIGHT | DOWN
```

--------------------------------

### Scallop Sampling with Top K

Source: https://www.scallop-lang.org/doc/print

Demonstrates how to use the 'top' sampler in Scallop to retrieve the k facts with the highest probabilities. This rule defines how to get the top-ranked symbol from a relation.

```scallop
rel symbols = {0.9::"+", 0.05::"-", 0.02::"3"}
rel top_symbol(s) = s := top<1>(s: symbols(s)) // 0.9::top_symbol("+")
```

--------------------------------

### Adding Programs to ScallopContext

Source: https://www.scallop-lang.org/doc/scallopy/context

Shows methods for loading Scallop programs into an initialized context. Programs can be added directly as a Python string or by importing an external '.scl' file.

```python
ctx.add_program("\n  rel edge = {(0, 1), (1, 2)}\n  rel path(a, c) = edge(a, c) or path(a, b) and edge(b, c)\n")

ctx.import_file("edge_path.scl")
```

--------------------------------

### Scallop Sum Aggregator (Incorrect Usage)

Source: https://www.scallop-lang.org/doc/print

Shows an example of incorrect usage of the 'sum' aggregator by omitting the argument variable, which can lead to deduplication of values before summation, resulting in an inaccurate total.

```scallop
rel total_sales_wrong(s) = s := sum(sp: sales(p, sp)) // 2200.0, since the two 1000.0 will be deduplicated without its key
```

--------------------------------

### Scallop Negation Example

Source: https://www.scallop-lang.org/doc/print

Demonstrates the use of negation (`not`) in Scallop rules to derive facts, such as identifying individuals with no children. It highlights how negation helps in expressing conditions like 'absence of a relation'.

```Scallop
rel person = {"bob", "alice", "christine"} // There are three persons of interest
rel father = {("bob", "alice")}            // Bob is Alice's father
rel mother = {("alice", "christine")}      // Alice is Christine's mother

rel has_no_child(n) = person(n) and not father(n, _) and not mother(n, _)

// Result:
has_no_child: {("christine",)}
```

--------------------------------

### Invoking Debug Module and Output Structure

Source: https://www.scallop-lang.org/doc/scallopy/debug_proofs

Demonstrates how to call a Scallop module configured for debugging and explains the structure of the returned output, which includes both the result tensor and detailed proofs.

```python
(result_tensor, proofs) = sum_2(digit_a=digit_a, digit_b=digit_b)
```

--------------------------------

### Add Scallop Program to Context

Source: https://www.scallop-lang.org/doc/print

Shows two methods for loading Scallop programs into a context: directly inserting a program as a Python string or importing it from an external '.scl' file. This allows defining relations and rules for computation.

```python
ctx.add_program(""
  rel edge = {(0, 1), (1, 2)}
  rel path(a, c) = edge(a, c) or path(a, b) and edge(b, c)
"")
```

```python
ctx.import_file("edge_path.scl")
```

--------------------------------

### Scallop: Boolean Declaration and Usage

Source: https://www.scallop-lang.org/doc/language/value_type

Demonstrates the use of boolean values in Scallop. It shows how to declare a relation `variable_assign` with a boolean type and provides an example of a logical operation.

```scallop
type variable_assign(String, bool)
rel variable_assign = {("a", true), ("b", false)}

rel result(a ^ b) = variable_assign("a", a) and variable_assign("b", b) // true
```
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