From 6bff474a8295f3b46c03622fd8ffa5239dd08803 Mon Sep 17 00:00:00 2001
From: markus holzer <markus.holzer@fau.de>
Date: Sat, 8 Aug 2020 13:58:43 +0200
Subject: [PATCH] Added test case for LinearEquationSystem
---
pystencils/utils.py | 6 +-----
pystencils_tests/test_utils.py | 36 ++++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+), 5 deletions(-)
create mode 100644 pystencils_tests/test_utils.py
diff --git a/pystencils/utils.py b/pystencils/utils.py
index f089dad1b..6cbe324e9 100644
--- a/pystencils/utils.py
+++ b/pystencils/utils.py
@@ -206,6 +206,7 @@ class LinearEquationSystem:
non_zero_rows = self.next_zero_row
num_unknowns = len(self.unknowns)
if non_zero_rows == 0:
+ print("test")
return 'multiple'
*row_begin, left, right = self._matrix.row(non_zero_rows - 1)
@@ -239,8 +240,3 @@ class LinearEquationSystem:
break
result -= 1
self.next_zero_row = result
-
-
-def find_unique_solutions_with_zeros(system: LinearEquationSystem):
- if not system.solution_structure() != 'multiple':
- raise ValueError("Function works only for underdetermined systems")
diff --git a/pystencils_tests/test_utils.py b/pystencils_tests/test_utils.py
new file mode 100644
index 000000000..0cc2895ba
--- /dev/null
+++ b/pystencils_tests/test_utils.py
@@ -0,0 +1,36 @@
+import sympy as sp
+from pystencils.utils import LinearEquationSystem
+
+
+def test_LinearEquationSystem():
+ x, y, z = sp.symbols("x, y, z")
+ les = LinearEquationSystem([x, y, z])
+ les.add_equation(1 * x + 2 * y - 1 * z + 4)
+ les.add_equation(2 * x + 1 * y + 1 * z - 2)
+ les.add_equation(1 * x + 2 * y + 1 * z + 2)
+
+ # usually reduce is not necessary since almost every function of LinearEquationSystem calls reduce beforehand
+ les.reduce()
+
+ expected_matrix = sp.Matrix([[1, 0, 0, sp.Rational(5, 3)],
+ [0, 1, 0, sp.Rational(-7, 3)],
+ [0, 0, 1, sp.Integer(1)]])
+ assert les.matrix == expected_matrix
+ assert les.rank == 3
+
+ sol = les.solution()
+ assert sol[x] == sp.Rational(5, 3)
+ assert sol[y] == sp.Rational(-7, 3)
+ assert sol[z] == sp.Integer(1)
+
+ les = LinearEquationSystem([x, y])
+ assert les.solution_structure() == 'multiple'
+
+ les.add_equation(x + 1)
+ assert les.solution_structure() == 'multiple'
+
+ les.add_equation(y + 2)
+ assert les.solution_structure() == 'single'
+
+ les.add_equation(x + y + 5)
+ assert les.solution_structure() == 'none'
--
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