Make the global deformation work with new PETSc

Replace calls to `getVec...` with `createVec` for better petsc4py / PETSc match
Refactor the way the transfer matrix is used for the global deformation (createVec does not have to be called here)

cashocs/_forms/control_form_handler.py

@@ -173,7 +173,7 @@ def scalar_product(
             x = fenics.as_backend_type(a[i].vector()).vec()
             y = fenics.as_backend_type(b[i].vector()).vec()
 
-            temp, _ = self.riesz_projection_matrices[i].getVecs()
+            temp = self.riesz_projection_matrices[i].createVecRight()
             self.riesz_projection_matrices[i].mult(x, temp)
             result += temp.dot(y)
 

cashocs/_forms/shape_form_handler.py

@@ -680,7 +680,7 @@ def scalar_product(
             x = fenics.as_backend_type(a[0].vector()).vec()
             y = fenics.as_backend_type(b[0].vector()).vec()
 
-            temp, _ = self.scalar_product_matrix.getVecs()
+            temp = self.scalar_product_matrix.createVecRight()
             self.scalar_product_matrix.mult(x, temp)
             result = temp.dot(y)
 

cashocs/_optimization/line_search/line_search.py

@@ -122,9 +122,9 @@ def perform(
 
             transfer_matrix = cast(PETSc.Mat, transfer_matrix)
 
-            _, temp = transfer_matrix.getVecs()
-            transfer_matrix.mult(x, temp)
-            self.global_deformation_vector.axpy(1.0, temp)
+            transfer_matrix.multAdd(
+                x, self.global_deformation_vector, self.global_deformation_vector
+            )
             self.deformation_function.vector().apply("")
 
         self.post_line_search()

cashocs/_utils/linalg.py

@@ -482,10 +482,10 @@ def solve(
         A = setup_matrix_and_preconditioner(ksp, A, P)
 
         if b is None:
-            return A.getVecs()[0]
+            return A.createVecRight()
 
         if fun is None:
-            x, _ = A.getVecs()
+            x = A.createVecRight()
         else:
             x = fun.vector().vec()