🐛 fix ε accuracy

tests/test_partial_derivative.py

@@ -6,6 +6,7 @@
 import logging
 
 from mbcp.mp_math.mp_math_typing import RealNumber
+from mbcp.mp_math.utils import Approx
 
 
 def three_var_func(x: RealNumber, y: RealNumber) -> RealNumber:
@@ -26,6 +27,7 @@ class TestPartialDerivative:
         def df_dx(x, y):
             """原函数关于x的偏导"""
             return 3 * (x ** 2) * (y ** 2) - 3 * (y ** 3) - y
+
         logging.info(f"Expected: {df_dx(1, 2)}, Actual: {partial_derivative_func(1, 2)}")
         assert Approx(partial_derivative_func(1, 2)) == df_dx(1, 2)
 
@@ -40,6 +42,7 @@ class TestPartialDerivative:
         def df_dy(x, y):
             """原函数关于y的偏导"""
             return 2 * (x ** 3) * y - 9 * x * (y ** 2) - x
+
         logging.info(f"Expected: {df_dy(1, 2)}, Actual: {partial_derivative_func(1, 2)}")
         assert Approx(partial_derivative_func(1, 2)) == df_dy(1, 2)
 
@@ -54,6 +57,7 @@ class TestPartialDerivative:
         def df_dxdy(x, y):
             """原函数关于y和x的偏导"""
             return 6 * x ** 2 * y - 9 * y ** 2 - 1
+
         logging.info(f"Expected: {df_dxdy(1, 2)}, Actual: {partial_derivative_func(1, 2)}")
         assert Approx(partial_derivative_func(1, 2)) == df_dxdy(1, 2)
 
@@ -63,11 +67,12 @@ class TestPartialDerivative:
         from mbcp.mp_math.utils import Approx
         from mbcp.mp_math.equation import get_partial_derivative_func
 
-        partial_derivative_func = get_partial_derivative_func(three_var_func, (0 , 0))
+        partial_derivative_func = get_partial_derivative_func(three_var_func, (0, 0))
 
         def df_dydx(x, y):
             """原函数关于x和y的偏导"""
             return 6 * x * y ** 2
+
         logging.info(f"Expected: {df_dydx(1, 2)}, Actual: {partial_derivative_func(1, 2)}")
         assert Approx(partial_derivative_func(1, 2)) == df_dydx(1, 2)
 
@@ -82,5 +87,15 @@ class TestPartialDerivative:
         def d3f_dx3(x, y):
             """原函数关于x的三阶偏导"""
             return 6 * (y ** 2)
+
         logging.info(f"Expected: {d3f_dx3(1, 2)}, Actual: {partial_derivative_func(1, 2)}")
         assert Approx(partial_derivative_func(1, 2)) == d3f_dx3(1, 2)
+
+    def test_possible_error(self):
+        from mbcp.mp_math.equation import get_partial_derivative_func
+        def two_vars_func(x: RealNumber, y: RealNumber) -> RealNumber:
+            return x ** 2 * y ** 2
+
+        partial_func = get_partial_derivative_func(two_vars_func, 0)
+        partial_func_2 = get_partial_derivative_func(two_vars_func, (0, 0))
+        assert Approx(partial_func_2(1, 2)) == 8