Refactor: Remove bpcg dependency on Psi and Hamilt

source/module_hsolver/diago_bpcg.cpp

@@ -27,14 +27,14 @@ DiagoBPCG<T, Device>::DiagoBPCG(const Real* precondition_in)
 template<typename T, typename Device>
 DiagoBPCG<T, Device>::~DiagoBPCG() {
     // Note, we do not need to free the h_prec and psi pointer as they are refs to the outside data
-    delete this->grad_wrapper;
 }
 
 template<typename T, typename Device>
-void DiagoBPCG<T, Device>::init_iter(const psi::Psi<T, Device> &psi_in) {
+void DiagoBPCG<T, Device>::init_iter(const int nband, const int nbasis) {
     // Specify the problem size n_basis, n_band, while lda is n_basis
-    this->n_band        = psi_in.get_nbands();
-    this->n_basis       = psi_in.get_nbasis();
+    this->n_band        = nband;
+    this->n_basis       = nbasis;
+
 
     // All column major tensors
 
@@ -51,9 +51,7 @@ void DiagoBPCG<T, Device>::init_iter(const psi::Psi<T, Device> &psi_in) {
 
     this->prec          = std::move(ct::Tensor(r_type, device_type, {this->n_basis}));
 
-    //TODO: Remove class Psi, using ct::Tensor instead!
-    this->grad_wrapper  = new psi::Psi<T, Device>(1, this->n_band, this->n_basis, psi_in.get_ngk_pointer());
-    this->grad          = std::move(ct::TensorMap(grad_wrapper->get_pointer(), t_type, device_type, {this->n_band, this->n_basis}));
+    this->grad          = std::move(ct::Tensor(t_type, device_type, {this->n_band, this->n_basis}));
 }
 
 template<typename T, typename Device>
@@ -174,16 +172,12 @@ void DiagoBPCG<T, Device>::rotate_wf(
 
 template<typename T, typename Device>
 void DiagoBPCG<T, Device>::calc_hpsi_with_block(
-        hamilt::Hamilt<T, Device>* hamilt_in,
-        const psi::Psi<T, Device>& psi_in,
+        const HPsiFunc& hpsi_func,
+        T *psi_in,
         ct::Tensor& hpsi_out)
 {
     // calculate all-band hpsi
-    psi::Range all_bands_range(1, psi_in.get_current_k(), 0, psi_in.get_nbands() - 1);
-    hpsi_info info(&psi_in, all_bands_range, hpsi_out.data<T>());
-    hamilt_in->ops->hPsi(info);
-
-    return;
+    hpsi_func(psi_in, hpsi_out.data<T>(), this->n_basis, this->n_band);
 }
 
 template<typename T, typename Device>
@@ -207,16 +201,16 @@ void DiagoBPCG<T, Device>::diag_hsub(
 
 template<typename T, typename Device>
 void DiagoBPCG<T, Device>::calc_hsub_with_block(
-        hamilt::Hamilt<T, Device> *hamilt_in,
-        const psi::Psi<T, Device> &psi_in,
+        const HPsiFunc& hpsi_func,
+        T *psi_in,
         ct::Tensor& psi_out,
         ct::Tensor& hpsi_out,
         ct::Tensor& hsub_out,
         ct::Tensor& workspace_in,
         ct::Tensor& eigenvalue_out)
 {
     // Apply the H operator to psi and obtain the hpsi matrix.
-    this->calc_hpsi_with_block(hamilt_in, psi_in, hpsi_out);
+    this->calc_hpsi_with_block(hpsi_func, psi_in, hpsi_out);
 
     // Diagonalization of the subspace matrix.
     this->diag_hsub(psi_out,hpsi_out, hsub_out, eigenvalue_out);
@@ -250,19 +244,19 @@ void DiagoBPCG<T, Device>::calc_hsub_with_block_exit(
 
 template<typename T, typename Device>
 void DiagoBPCG<T, Device>::diag(
-        hamilt::Hamilt<T, Device>* hamilt_in,
-        psi::Psi<T, Device>& psi_in,
+        const HPsiFunc& hpsi_func,
+        T *psi_in,
         Real* eigenvalue_in)
 {
     const int current_scf_iter = hsolver::DiagoIterAssist<T, Device>::SCF_ITER;
     // Get the pointer of the input psi
-    this->psi = std::move(ct::TensorMap(psi_in.get_pointer(), t_type, device_type, {this->n_band, this->n_basis}));
+    this->psi = std::move(ct::TensorMap(psi_in /*psi_in.get_pointer()*/, t_type, device_type, {this->n_band, this->n_basis}));
 
     // Update the precondition array
     this->calc_prec();
 
     // Improving the initial guess of the wave function psi through a subspace diagonalization.
-    this->calc_hsub_with_block(hamilt_in, psi_in, this->psi, this->hpsi, this->hsub, this->work, this->eigen);
+    this->calc_hsub_with_block(hpsi_func, psi_in, this->psi, this->hpsi, this->hsub, this->work, this->eigen);
 
     setmem_complex_op()(this->grad_old.template data<T>(), 0, this->n_basis * this->n_band);
 
@@ -293,7 +287,7 @@ void DiagoBPCG<T, Device>::diag(
         syncmem_complex_op()(this->grad_old.template data<T>(), this->grad.template data<T>(), n_basis * n_band);
 
         // Calculate H|grad> matrix
-        this->calc_hpsi_with_block(hamilt_in, this->grad_wrapper[0], this->hgrad);
+        this->calc_hpsi_with_block(hpsi_func, this->grad.template data<T>(), /*this->grad_wrapper[0],*/ this->hgrad);
 
         // optimize psi as well as the hpsi
         // 1. normalize grad
@@ -305,7 +299,7 @@ void DiagoBPCG<T, Device>::diag(
         this->orth_cholesky(this->work, this->psi, this->hpsi, this->hsub);
 
         if (current_scf_iter == 1 && ntry % this->nline == 0) {
-            this->calc_hsub_with_block(hamilt_in, psi_in, this->psi, this->hpsi, this->hsub, this->work, this->eigen);
+            this->calc_hsub_with_block(hpsi_func, psi_in, this->psi, this->hpsi, this->hsub, this->work, this->eigen);
         }
     } while (ntry < max_iter && this->test_error(this->err_st, this->all_band_cg_thr));
 

source/module_hsolver/diago_bpcg.h

@@ -50,20 +50,24 @@ class DiagoBPCG
      * This function allocates all the related variables, such as hpsi, hsub, before the diag call.
      * It is called by the HsolverPW::initDiagh() function.
      *
-     * @param psi_in The input wavefunction psi.
+     * @param nband The number of bands.
+     * @param nbasis The number of basis functions. Leading dimension of psi.
      */
-    void init_iter(const psi::Psi<T, Device> &psi_in);
+    void init_iter(const int nband, const int nbasis);
+
+    using HPsiFunc = std::function<void(T*, T*, const int, const int)>;
 
     /**
      * @brief Diagonalize the Hamiltonian using the BPCG method.
      *
      * This function is called by the HsolverPW::solve() function.
      *
-     * @param phm_in A pointer to the hamilt::Hamilt object representing the Hamiltonian operator.
-     * @param psi The input wavefunction psi matrix with [dim: n_basis x n_band, column major].
+     * @param hpsi_func A function computing the product of the Hamiltonian matrix H
+     * and a wavefunction blockvector X.
+     * @param psi_in Pointer to input wavefunction psi matrix with [dim: n_basis x n_band, column major].
      * @param eigenvalue_in Pointer to the eigen array with [dim: n_band, column major].
      */
-    void diag(hamilt::Hamilt<T, Device> *phm_in, psi::Psi<T, Device> &psi, Real *eigenvalue_in);
+    void diag(const HPsiFunc& hpsi_func, T *psi_in, Real *eigenvalue_in);
 
 
   private:
@@ -103,7 +107,6 @@ class DiagoBPCG
     /// work for some calculations within this class, including rotate_wf call
     ct::Tensor work = {};
 
-    psi::Psi<T, Device>* grad_wrapper;
     /**
      * @brief Update the precondition array.
      *
@@ -134,13 +137,14 @@ class DiagoBPCG
      * psi_in[dim: n_basis x n_band, column major, lda = n_basis_max],
      * hpsi_out[dim: n_basis x n_band, column major, lda = n_basis_max].
      *
-     * @param hamilt_in A pointer to the hamilt::Hamilt object representing the Hamiltonian operator.
+     * @param hpsi_func A function computing the product of the Hamiltonian matrix H
+     * and a wavefunction blockvector X.
      * @param psi_in The input wavefunction psi.
      * @param hpsi_out Pointer to the array where the resulting hpsi matrix will be stored.
      */
     void calc_hpsi_with_block(
-        hamilt::Hamilt<T, Device>* hamilt_in, 
-        const psi::Psi<T, Device>& psi_in,  
+        const HPsiFunc& hpsi_func,
+        T *psi_in, 
         ct::Tensor& hpsi_out);
 
     /**
@@ -220,16 +224,16 @@ class DiagoBPCG
      * hsub_out[dim: n_band x n_band, column major, lda = n_band],
      * eigenvalue_out[dim: n_basis_max, column major].
      *
-     * @param hamilt_in Pointer to the Hamiltonian object.
-     * @param psi_in Input wavefunction.
+     * @param hpsi_func A function computing the product of matrix H and wavefunction blockvector X.
+     * @param psi_in Input wavefunction pointer.
      * @param psi_out Output wavefunction.
      * @param hpsi_out Product of psi_out and Hamiltonian.
      * @param hsub_out Subspace matrix output.
      * @param eigenvalue_out Computed eigen.
      */
     void calc_hsub_with_block(
-        hamilt::Hamilt<T, Device>* hamilt_in,
-        const psi::Psi<T, Device>& psi_in,
+        const HPsiFunc& hpsi_func,
+        T *psi_in,
         ct::Tensor& psi_out, ct::Tensor& hpsi_out,
         ct::Tensor& hsub_out, ct::Tensor& workspace_in,
         ct::Tensor& eigenvalue_out);
@@ -314,8 +318,6 @@ class DiagoBPCG
      */
     bool test_error(const ct::Tensor& err_in, Real thr_in);
 
-    using hpsi_info = typename hamilt::Operator<T, Device>::hpsi_info;
-
     using ct_Device = typename ct::PsiToContainer<Device>::type;
     using setmem_var_op = ct::kernels::set_memory<Real, ct_Device>;
     using resmem_var_op = ct::kernels::resize_memory<Real, ct_Device>;

source/module_hsolver/hsolver_pw.cpp

@@ -467,9 +467,27 @@ void HSolverPW<T, Device>::hamiltSolvePsiK(hamilt::Hamilt<T, Device>* hm,
     }
     else if (this->method == "bpcg")
     {
+        const int nband  = psi.get_nbands();
+        const int nbasis = psi.get_nbasis();
+        auto ngk_pointer = psi.get_ngk_pointer();
+        // hpsi_func (X, HX, ld, nvec) -> HX = H(X), X and HX blockvectors of size ld x nvec
+        auto hpsi_func = [hm, ngk_pointer](T* psi_in, T* hpsi_out, const int ld_psi, const int nvec) {
+            ModuleBase::timer::tick("DavSubspace", "hpsi_func");
+
+            // Convert "pointer data stucture" to a psi::Psi object
+            auto psi_iter_wrapper = psi::Psi<T, Device>(psi_in, 1, nvec, ld_psi, ngk_pointer);
+
+            psi::Range bands_range(true, 0, 0, nvec - 1);
+
+            using hpsi_info = typename hamilt::Operator<T, Device>::hpsi_info;
+            hpsi_info info(&psi_iter_wrapper, bands_range, hpsi_out);
+            hm->ops->hPsi(info);
+
+            ModuleBase::timer::tick("DavSubspace", "hpsi_func");
+        };
         DiagoBPCG<T, Device> bpcg(pre_condition.data());
-        bpcg.init_iter(psi);
-        bpcg.diag(hm, psi, eigenvalue);
+        bpcg.init_iter(nband, nbasis);
+        bpcg.diag(hpsi_func, psi.get_pointer(), eigenvalue);
     }
     else if (this->method == "dav_subspace")
     {

source/module_hsolver/test/diago_bpcg_test.cpp

@@ -130,10 +130,32 @@ class DiagoBPCGPrepare
         psi_local.fix_k(0);
         double start, end;
         start = MPI_Wtime();
-        bpcg.init_iter(psi_local);
-        bpcg.diag(ha,psi_local,en); 
-        bpcg.diag(ha,psi_local,en); 
-        bpcg.diag(ha,psi_local,en); 
+        using T = std::complex<double>;
+        const int dim = DIAGOTEST::npw;
+        const std::vector<T> &h_mat = DIAGOTEST::hmatrix_local;
+        auto hpsi_func = [h_mat, dim](T *psi_in, T *hpsi_out,
+                                const int ld_psi, const int nvec) {
+            auto one = std::make_unique<T>(1.0);
+            auto zero = std::make_unique<T>(0.0);
+            const T *one_ = one.get();
+            const T *zero_ = zero.get();
+
+            base_device::DEVICE_CPU *ctx = {};
+            // hpsi_out(dim * nvec) = h_mat(dim * dim) * psi_in(dim * nvec)
+            hsolver::gemm_op<T, base_device::DEVICE_CPU>()(
+                ctx, 'N', 'N',
+                dim, nvec, dim,
+                one_,
+                h_mat.data(), dim,
+                psi_in, ld_psi,
+                zero_,
+                hpsi_out, ld_psi);
+        };
+        bpcg.init_iter(nband, npw);
+        bpcg.diag(hpsi_func, psi_local.get_pointer(), en);
+        bpcg.diag(hpsi_func, psi_local.get_pointer(), en);
+        bpcg.diag(hpsi_func, psi_local.get_pointer(), en);
+        bpcg.diag(hpsi_func, psi_local.get_pointer(), en);
         end = MPI_Wtime();
         //if(mypnum == 0) printf("diago time:%7.3f\n",end-start);
         delete [] DIAGOTEST::npw_local;
@@ -219,29 +241,6 @@ TEST(DiagoBPCGTest, Hamilt)
     }
 }*/
 
-// bpcg for a 2x2 matrix
-#ifdef __MPI
-#else
-TEST(DiagoBPCGTest, TwoByTwo)
-{
-    int dim = 2;
-    int nband = 2;
-    ModuleBase::ComplexMatrix hm(2, 2);
-    hm(0, 0) = std::complex<double>{4.0, 0.0};
-    hm(0, 1) = std::complex<double>{1.0, 0.0};
-    hm(1, 0) = std::complex<double>{1.0, 0.0};
-    hm(1, 1) = std::complex<double>{3.0, 0.0};
-    // nband, npw, sub, sparsity, reorder, eps, maxiter, threshold
-    DiagoBPCGPrepare dcp(nband, dim, 0, true, 1e-4, 50, 1e-10);
-    hsolver::DiagoIterAssist<std::complex<double>>::PW_DIAG_NMAX = dcp.maxiter;
-    hsolver::DiagoIterAssist<std::complex<double>>::PW_DIAG_THR = dcp.eps;
-    HPsi<std::complex<double>> hpsi;
-    hpsi.create(nband, dim);
-    DIAGOTEST::hmatrix = hm;
-    DIAGOTEST::npw = dim;
-    dcp.CompareEigen(hpsi.precond());
-}
-#endif
 
 TEST(DiagoBPCGTest, readH)
 {