feat: Adding semi-continous

dandxy89 · Nov 11, 2023 · 51eae33 · 51eae33
1 parent 663f295
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Showing 6 changed files with 77 additions and 28 deletions.
diff --git a/README.md b/README.md
@@ -18,17 +18,17 @@ A Rust LP file parser leveraging [PEST](https://docs.rs/pest/latest/pest/) and a
 - Constraints
 - Bounds
 - Variable Types: Integer, Generals, Lower Bounded, Upper Bounded, Free & Upper and Lower Bounded
+- Semi-continuous
 
 ## TODOs List
 
 - Remaining LP format changes:
-  - Semi-continuous
-    - <https://www.ibm.com/docs/en/icos/22.1.1?topic=representation-mip-features-in-lp-file-format#File_formats_reference.uss_reffileformatscplex.LP_MIP__File_formats_reference.uss_reffileformatscplex.177272__title__1>
-    - <https://www.fico.com/fico-xpress-optimization/docs/dms2020-03/solver/optimizer/HTML/chapter10_sec_section102.html>
   - Special ordered sets: SOS
     - Keyword: `SOS`
     - Example: `Sos101: 1.2 x1 + 1.3 x2 + 1.4 x4 = S1`
   - Lazy Constraints
+  - Semi-Continuous
+    - See details in FICO® Xpress
 - Extensions:
   - Compares two LP files
   - CLI

diff --git a/resources/semi_continuous.lp b/resources/semi_continuous.lp
@@ -0,0 +1,18 @@
+Minimize
+ b_5829890_x2
+ + b_5880854_x2
+Subject To
+ - 2 b_5829890_x2 + 2 b_5829890_x1 <= -64
+b_5880854_x2 - b_5880854_x1 >= 32
+Bounds
+b_5829890_x1 >= 10 
+10 >= b_5880854_x1 
+1014 <= b_5829890_x2 <= 1917
+1014 <= b_5880854_x2 <= 1917
+Generals 
+b_5829890_x2 b_5880854_x2
+Binary
+b_5829890_x1
+Semi-continuous
+x1 x2 x3
+End
diff --git a/src/lp_file_format.pest b/src/lp_file_format.pest
@@ -43,14 +43,15 @@ PROBLEM_SENSE = _{ NEWLINE* ~ (MIN_SENSE | MAX_SENSE) }
 // https://www.ibm.com/docs/en/icos/22.1.1?topic=representation-variable-names-in-lp-file-format
 // alphanumeric (a-z, A-Z, 0-9) or one of these symbols: !"#$%&/,.;?@_`'{}()|~'
 VALID_CHARS       = _{
-    !(FREE | END | CONSTRAINT_PREFIX) ~ (ASCII_ALPHANUMERIC | "!" | "#" | "$" | "%" | "&" | "(" | ")" | "," | "." | ";" | "?" | "@" | "_" | "‘" | "’" | "{" | "}" | "~")
+    !WHITESPACE ~ (ASCII_ALPHANUMERIC | "!" | "#" | "$" | "%" | "&" | "(" | ")" | "," | "." | ";" | "?" | "@" | "_" | "‘" | "’" | "{" | "}" | "~")
 }
 CONSTRAINT_PREFIX = _{
     (^"subject to" | ^"such that" | ^"S.T.") ~ COLON? ~ NEWLINE?
 }
 VARIABLE          =  {
-    !(FREE | END | CONSTRAINT_PREFIX | GENERALS_PREFIX | BINARIES_PREFIX) ~ VALID_CHARS{1, 255}
+    !(FREE | END | CONSTRAINT_PREFIX | GENERALS_PREFIX | BINARIES_PREFIX | SEMI_CONTINUOUS_PREFIX) ~ VALID_CHARS{1, 255}
 }
+SEMI_VARIABLE     =  { !(FREE | END | CONSTRAINT_PREFIX | GENERALS_PREFIX | BINARIES_PREFIX | SEMI_CONTINUOUS_PREFIX) ~ VALID_CHARS ~ (!WHITESPACE ~ VALID_CHARS) }
 
 // Objective function
 // https://www.ibm.com/docs/en/icos/22.1.1?topic=representation-objective-in-lp-file-format
@@ -109,12 +110,18 @@ GENERALS        =  { NEWLINE ~ GENERALS_PREFIX ~ (NEWLINE ~ VARIABLE)+ }
 BINARIES_PREFIX = _{ ^"Binar" ~ (^"ies" | ^"y") }
 BINARIES        =  { NEWLINE ~ BINARIES_PREFIX ~ (NEWLINE ~ VARIABLE)+ }
 
+// Semi-Continuous
+// To specify any of the variables as semi-continuous variables, that is as variables that
+// may take the value 0 or values between the specified lower and upper bounds
+SEMI_CONTINUOUS_PREFIX = _{ ^"SEMI" ~ (^"S" | ^"-CONTINUOUS") }
+SEMI_CONTINUOUS        =  { NEWLINE ~ SEMI_CONTINUOUS_PREFIX ~ (NEWLINE? ~ SEMI_VARIABLE)+ }
+
 // End of file
 // https://www.ibm.com/docs/en/icos/22.1.1?topic=representation-end-file-in-lp-file-format
 EOF = _{ NEWLINE* ~ END }
 
 // Global
-OPTIONAL_SECTIONS = _{ BOUNDS? ~ INTEGERS? ~ GENERALS? ~ BINARIES? ~ EOF? }
+OPTIONAL_SECTIONS = _{ BOUNDS? ~ INTEGERS? ~ GENERALS? ~ BINARIES? ~ SEMI_CONTINUOUS? ~ EOF? }
 LP_FILE           =  {
     LP_PROBLEM_NAME? ~ COMMENTS* ~ PROBLEM_SENSE ~ OBJECTIVES ~ CONSTRAINTS ~ OPTIONAL_SECTIONS
 }
diff --git a/src/lp_parts.rs b/src/lp_parts.rs
@@ -122,6 +122,14 @@ pub fn compose(pair: Pair<'_, Rule>, mut parsed: LPDefinition) -> anyhow::Result
                 }
             }
         }
+        // Problem Semi-continuous
+        Rule::SEMI_CONTINUOUS => {
+            for bin_pair in pair.into_inner() {
+                if matches!(bin_pair.as_rule(), Rule::SEMI_VARIABLE) {
+                    parsed.set_var_bounds(bin_pair.as_str(), VariableType::SemiContinuous);
+                }
+            }
+        }
         // Otherwise, skip!
         _ => (),
     }

diff --git a/src/model.rs b/src/model.rs
@@ -26,6 +26,8 @@ pub enum VariableType {
     #[default]
     // General variable [0, +Infinity]
     General,
+    // Semi-continuous
+    SemiContinuous,
 }
 
 #[derive(Debug)]
@@ -102,14 +104,18 @@ impl LPDefinition {
     }
 
     pub fn add_variable(&mut self, name: &str) {
-        self.variables.entry(name.to_string()).or_default();
+        if !name.is_empty() {
+            self.variables.entry(name.trim().to_string()).or_default();
+        }
     }
 
     pub fn set_var_bounds(&mut self, name: &str, kind: VariableType) {
-        match self.variables.entry(name.to_string()) {
-            Entry::Occupied(k) => *k.into_mut() = kind,
-            Entry::Vacant(k) => {
-                k.insert(kind);
+        if !name.is_empty() {
+            match self.variables.entry(name.trim().to_string()) {
+                Entry::Occupied(k) => *k.into_mut() = kind,
+                Entry::Vacant(k) => {
+                    k.insert(kind);
+                }
             }
         }
     }

diff --git a/tests/test_from_file.rs b/tests/test_from_file.rs
@@ -12,7 +12,7 @@ fn afiro() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 3);
     assert_eq!(result.constraints.len(), 27);
-    assert_eq!(result.variables.len(), 44);
+    assert_eq!(result.variables.len(), 32);
 }
 
 #[test]
@@ -22,7 +22,7 @@ fn afiro_ext() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 4);
     assert_eq!(result.constraints.len(), 27);
-    assert_eq!(result.variables.len(), 66);
+    assert_eq!(result.variables.len(), 47);
 }
 
 #[test]
@@ -32,7 +32,7 @@ fn boeing1() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 348);
-    assert_eq!(result.variables.len(), 856);
+    assert_eq!(result.variables.len(), 473);
 }
 
 #[test]
@@ -42,7 +42,7 @@ fn boeing2() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 140);
-    assert_eq!(result.variables.len(), 280);
+    assert_eq!(result.variables.len(), 162);
 }
 
 #[test]
@@ -52,7 +52,7 @@ fn fit1d() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 24);
-    assert_eq!(result.variables.len(), 2053);
+    assert_eq!(result.variables.len(), 1026);
 }
 
 #[test]
@@ -62,7 +62,7 @@ fn fit2d() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 25);
-    assert_eq!(result.variables.len(), 21001);
+    assert_eq!(result.variables.len(), 10500);
 }
 
 #[test]
@@ -72,7 +72,7 @@ fn kb2() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 43);
-    assert_eq!(result.variables.len(), 79);
+    assert_eq!(result.variables.len(), 41);
 }
 
 #[test]
@@ -82,7 +82,7 @@ fn pulp() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 49);
-    assert_eq!(result.variables.len(), 86);
+    assert_eq!(result.variables.len(), 62);
 }
 
 #[test]
@@ -92,7 +92,7 @@ fn pulp2() {
     assert_eq!(result.problem_sense, Sense::Maximize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 7);
-    assert_eq!(result.variables.len(), 148);
+    assert_eq!(result.variables.len(), 139);
 }
 
 #[test]
@@ -102,7 +102,7 @@ fn sc50a() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 49);
-    assert_eq!(result.variables.len(), 70);
+    assert_eq!(result.variables.len(), 48);
 }
 
 #[test]
@@ -118,7 +118,7 @@ fn no_end_section() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 4);
     assert_eq!(result.constraints.len(), 2);
-    assert_eq!(result.variables.len(), 6);
+    assert_eq!(result.variables.len(), 3);
 }
 
 #[test]
@@ -128,7 +128,7 @@ fn model2() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 4);
-    assert_eq!(result.variables.len(), 16);
+    assert_eq!(result.variables.len(), 8);
 }
 
 #[test]
@@ -138,7 +138,7 @@ fn limbo() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 2);
     assert_eq!(result.constraints.len(), 2);
-    assert_eq!(result.variables.len(), 8);
+    assert_eq!(result.variables.len(), 5);
 }
 
 #[test]
@@ -148,7 +148,7 @@ fn obj3_2cons() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 4);
     assert_eq!(result.constraints.len(), 2);
-    assert_eq!(result.variables.len(), 6);
+    assert_eq!(result.variables.len(), 3);
 }
 
 #[test]
@@ -158,7 +158,7 @@ fn obj_2cons_only_binary_vars() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 2);
     assert_eq!(result.constraints.len(), 2);
-    assert_eq!(result.variables.len(), 7);
+    assert_eq!(result.variables.len(), 4);
 }
 
 #[test]
@@ -168,7 +168,7 @@ fn obj_2cons_all_variable_types() {
     assert_eq!(result.problem_sense, Sense::Minimize);
     assert_eq!(result.objectives.len(), 2);
     assert_eq!(result.constraints.len(), 2);
-    assert_eq!(result.variables.len(), 7);
+    assert_eq!(result.variables.len(), 3);
 }
 
 #[test]
@@ -178,7 +178,17 @@ fn obj_1cons_all_variables_with_bounds() {
     assert_eq!(result.problem_sense, Sense::Maximize);
     assert_eq!(result.objectives.len(), 1);
     assert_eq!(result.constraints.len(), 1);
-    assert_eq!(result.variables.len(), 6);
+    assert_eq!(result.variables.len(), 3);
+}
+
+#[test]
+fn semi_continuous() {
+    let result = read_file_from_resources("semi_continuous.lp").unwrap();
+    assert_eq!("", result.problem_name);
+    assert_eq!(result.problem_sense, Sense::Minimize);
+    assert_eq!(result.objectives.len(), 2);
+    assert_eq!(result.constraints.len(), 2);
+    assert_eq!(dbg!(result.variables).len(), 8);
 }
 
 fn read_file_from_resources(file_name: &str) -> anyhow::Result<LPDefinition> {