Add __str__ dunder methods to a few classes

2 files changed, 34 insertions, 1 deletions

diff --git a/sumofsquares/abc.py b/sumofsquares/abc.py
index 482ba7f..95eacad 100644
--- a/sumofsquares/abc.py
+++ b/sumofsquares/abc.py
@@ -42,10 +42,27 @@ class Constraint(ABC):
     def expression(self) -> Expression:
         """ Expression under the constraint. """
 
+    def __str__(self):
+        return f"{self.__class__.__qualname__}({str(self.expression)})"
+
 
 class Problem(ABC):
     """ Optimization Problem. """
     
+    # --- dunder methods ---
+
+    def __str__(self):
+        vs = ", ".join(map(str, self.variables))
+        n = len(self.constraints)
+        s = f"SumOfSquares Problem ({self.__class__.__qualname__}):\n\n  " \
+                f"find      {vs}\n  minimize  {self.cost}\n  " \
+                f"subject to ({n} constraint{'s' if n > 1 else ''})\n"
+
+        for c in self.constraints:
+            s += f"\t* {str(c)}\n"
+
+        return s
+
     # --- Properties ---
 
     @property
diff --git a/sumofsquares/constraints.py b/sumofsquares/constraints.py
index 3634e61..41f2b14 100644
--- a/sumofsquares/constraints.py
+++ b/sumofsquares/constraints.py
@@ -1,11 +1,15 @@
+from dataclasses import dataclass
 from dataclassabc import dataclassabc
+from typing_extensions import override
+from typing import NamedTuple
 
 from polymatrix.expression.expression import Expression
 
 from .abc import Set, Constraint
 
 
-class ArchimedeanSet(Set, tuple[Expression]):
+@dataclass(frozen=True)
+class ArchimedeanSet(Set):
     r"""
     A set that is described by the intersection of the positive loci of a
     finite number of polynomials (under some conditions). Roughly speaking this
@@ -26,6 +30,10 @@ class ArchimedeanSet(Set, tuple[Expression]):
     Archimedean! It is assumed that the given :math:`g_i` make
     :math:`\mathbf{K}` Archimedean.
     """
+    polynomials: tuple[Expression]
+
+    def __str__(self):
+        return f"{self.__class__.__qualname__}({', '.join(map(str, self.polynomials))})"
 
 
 @dataclassabc(frozen=True)
@@ -48,3 +56,11 @@ class NonNegative(Constraint):
     """
     expression: Expression 
     domain: ArchimedeanSet | None = None
+
+    @override
+    def __str__(self):
+        s = f"{self.__class__.__qualname__}  {str(self.expression)}"
+        if self.domain:
+            s += f"\n\t\t over {self.domain}"
+        return s
+