diff --git a/python/taichi/linalg/matrixfree_cg.py b/python/taichi/linalg/matrixfree_cg.py
index 6af5ef177c387..0d333f4bbcea0 100644
--- a/python/taichi/linalg/matrixfree_cg.py
+++ b/python/taichi/linalg/matrixfree_cg.py
@@ -18,7 +18,7 @@ def matvec(self, x, Ax):
 
 def MatrixFreeCG(A, b, x, tol=1e-6, maxiter=5000, quiet=True):
     """Matrix-free conjugate-gradient solver.
-    
+
     Use conjugate-gradient method to solve the linear system Ax = b, where A is implicitly
     represented as a LinearOperator.
 
@@ -30,7 +30,7 @@ def MatrixFreeCG(A, b, x, tol=1e-6, maxiter=5000, quiet=True):
         atol: Tolerance(absolute) for convergence.
         quiet (bool): Switch to turn on/off iteration log.
     """
-    
+
     if b.dtype != x.dtype:
         raise TaichiTypeError(f"Dtype mismatch b.dtype({b.dtype}) != x.dtype({x.dtype}).")
     if str(b.dtype) == "f32":
diff --git a/python/taichi/linalg/sparse_cg.py b/python/taichi/linalg/sparse_cg.py
index 5ebdf663f5ca9..e0aba8112c690 100644
--- a/python/taichi/linalg/sparse_cg.py
+++ b/python/taichi/linalg/sparse_cg.py
@@ -8,7 +8,7 @@
 
 class SparseCG:
     """Conjugate-gradient solver built for SparseMatrix.
-    
+
     Use conjugate-gradient method to solve the linear system Ax = b, where A is SparseMatrix.
 
     Args:
@@ -18,7 +18,7 @@ class SparseCG:
         max_iter (int): Maximum number of iterations.
         atol: Tolerance(absolute) for convergence.
     """
-    
+
     def __init__(self, A, b, x0=None, max_iter=50, atol=1e-6):
         self.dtype = A.dtype
         self.ti_arch = get_runtime().prog.config().arch