refactor(parallel): rename bgroup domain to bdiff_ksame in module_parallel

The bgroup name is misleading: it does not say which two axes the domain
connects. Rename the new module_parallel band-group domain after its tag
bdiff_ksame (different band groups, same k), matching ParaTag:

  para_bgroup_world.{h,cpp}   -> para_bdiff_ksame_world.{h,cpp}
  ParaBgroupWorld             -> ParaBdiffKsameWorld
  make_bgroup_world()         -> make_bdiff_ksame_world()
  reduce_across_bgroups()     -> reduce_across_bdiff_ksame()

Legacy globals INT_BGROUP / BP_WORLD and the GlobalV::MY_BNDGROUP-style
member names are the old parallel-layer API and are left unchanged; the
new domain is only a self-contained bridge over them.

Author: abacus_fixer

source/Makefile.Objects

@@ -797,7 +797,7 @@ OBJS_PARALLEL=parallel_common.o\
     para_pw_world.o\
     para_diag_world.o\
     para_rgrid_world.o\
-    para_bgroup_world.o\
+    para_bdiff_ksame_world.o\
     para_matrix_world.o\
     para_mpi_func.o\
     para_setup.o\

source/source_base/CMakeLists.txt

@@ -79,7 +79,7 @@ add_library(
     module_parallel/para_pw_world.cpp
     module_parallel/para_diag_world.cpp
     module_parallel/para_rgrid_world.cpp
-    module_parallel/para_bgroup_world.cpp
+    module_parallel/para_bdiff_ksame_world.cpp
     module_parallel/para_matrix_world.cpp
     module_parallel/para_mpi_func.cpp
     module_parallel/para_setup.cpp

…se/module_parallel/para_bgroup_world.cpp …dule_parallel/para_bdiff_ksame_world.cppsource/source_base/module_parallel/para_bgroup_world.cpp renamed to source/source_base/module_parallel/para_bdiff_ksame_world.cpp source/source_base/module_parallel/para_bgroup_world.cpp renamed to source/source_base/module_parallel/para_bdiff_ksame_world.cpp

@@ -1,15 +1,15 @@
-#include "para_bgroup_world.h"
+#include "para_bdiff_ksame_world.h"
 
 namespace Parallel
 {
 
-ParaBgroupWorld::ParaBgroupWorld()
+ParaBdiffKsameWorld::ParaBdiffKsameWorld()
     : ParaWorld("bdiff_ksame"), my_bndgroup_(0), nbndgroup_(1)
 {
 }
 
 #ifdef __MPI
-ParaBgroupWorld::ParaBgroupWorld(const MPI_Comm& intra_comm, const MPI_Comm& inter_comm, int nbndgroup)
+ParaBdiffKsameWorld::ParaBdiffKsameWorld(const MPI_Comm& intra_comm, const MPI_Comm& inter_comm, int nbndgroup)
     : ParaWorld("bdiff_ksame", intra_comm), inter_comm_(inter_comm), nbndgroup_(nbndgroup)
 {
     if (inter_comm != MPI_COMM_NULL)
@@ -19,7 +19,7 @@ ParaBgroupWorld::ParaBgroupWorld(const MPI_Comm& intra_comm, const MPI_Comm& int
 }
 #endif
 
-void ParaBgroupWorld::reduce_across_bgroups(double& value) const
+void ParaBdiffKsameWorld::reduce_across_bdiff_ksame(double& value) const
 {
 #ifdef __MPI
     if (inter_comm_ == MPI_COMM_NULL || nbndgroup_ <= 1)

…base/module_parallel/para_bgroup_world.h …module_parallel/para_bdiff_ksame_world.hsource/source_base/module_parallel/para_bgroup_world.h renamed to source/source_base/module_parallel/para_bdiff_ksame_world.h source/source_base/module_parallel/para_bgroup_world.h renamed to source/source_base/module_parallel/para_bdiff_ksame_world.h

@@ -1,40 +1,41 @@
-#ifndef PARA_BGROUP_WORLD_H
-#define PARA_BGROUP_WORLD_H
+#ifndef PARA_BDIFF_KSAME_WORLD_H
+#define PARA_BDIFF_KSAME_WORLD_H
 
 #include "para_world.h"
 
 namespace Parallel
 {
 
 /**
- * @brief bgroup parallel domain: band group communication topology.
+ * @brief bdiff_ksame parallel domain: band-group communication topology
+ * inside one k-pool.
  *
  * Self-contained replacement for INT_BGROUP + BP_WORLD +
  * GlobalV::MY_BNDGROUP/NPROC_IN_BNDGROUP/RANK_IN_BPGROUP.
  *
- * The band group domain has two communicators:
- *   - intra: INT_BGROUP (same band group, different k/pw)
- *   - inter: BP_WORLD (different band groups, same k)
+ * The domain has two communicators:
+ *   - intra: INT_BGROUP (bsame_kdiff; same band group, different k/pw)
+ *   - inter: BP_WORLD  (bdiff_ksame; different band groups, same k)
  *
  * Tests only need this header.
  */
-class ParaBgroupWorld : public ParaWorld
+class ParaBdiffKsameWorld : public ParaWorld
 {
 public:
     /**
-     * @brief Construct a serial bgroup domain (single band group).
+     * @brief Construct a serial domain (single band group).
      */
-    ParaBgroupWorld();
+    ParaBdiffKsameWorld();
 
 #ifdef __MPI
     /**
-     * @brief Construct a bgroup domain from intra and inter communicators.
+     * @brief Construct a domain from intra and inter communicators.
      *
      * @param[in] intra_comm  intra-group communicator (e.g. INT_BGROUP)
      * @param[in] inter_comm  inter-group communicator (e.g. BP_WORLD)
      * @param[in] nbndgroup   number of band groups
      */
-    ParaBgroupWorld(const MPI_Comm& intra_comm, const MPI_Comm& inter_comm, int nbndgroup);
+    ParaBdiffKsameWorld(const MPI_Comm& intra_comm, const MPI_Comm& inter_comm, int nbndgroup);
 #endif
 
     /// Band group index of this process.
@@ -50,7 +51,7 @@ class ParaBgroupWorld : public ParaWorld
     int nproc_in_bndgroup() const { return size(); }
 
 #ifdef __MPI
-    /// Inter-group communicator (BP_WORLD equivalent).
+    /// Inter-group communicator (BP_WORLD / bdiff_ksame equivalent).
     MPI_Comm inter_comm() const { return inter_comm_; }
 #endif
 
@@ -60,9 +61,9 @@ class ParaBgroupWorld : public ParaWorld
      * Band-parallel eigensolvers (bpcg) shard the band range across the
      * BNDPAR band groups of a k-pool: every process only accumulates the
      * partial sum over its own band window. This reduction combines those
-     * partial sums on BP_WORLD (bdiff_ksame), which links the same rank
-     * position of every band group inside one k-pool, so each band window
-     * contributes exactly once.
+     * partial sums on the bdiff_ksame (BP_WORLD) communicator, which links
+     * the same rank position of every band group inside one k-pool, so each
+     * band window contributes exactly once.
      *
      * It must run BEFORE ParaKmeshWorld::reduce_across_pools so that the
      * k-pool reduction receives one complete per-k-pool partial sum.
@@ -71,7 +72,7 @@ class ParaBgroupWorld : public ParaWorld
      * @param[in,out] value  local partial sum, overwritten with the
      *                       k-pool-wide total
      */
-    void reduce_across_bgroups(double& value) const;
+    void reduce_across_bdiff_ksame(double& value) const;
 
 private:
     int my_bndgroup_ = 0;
@@ -83,4 +84,4 @@ class ParaBgroupWorld : public ParaWorld
 
 } // namespace Parallel
 
-#endif // PARA_BGROUP_WORLD_H
+#endif // PARA_BDIFF_KSAME_WORLD_H

source/source_base/module_parallel/para_bridge.cpp

@@ -59,9 +59,9 @@ ParaKmeshWorld make_kmesh_world(int nkstot, int nspin)
     return ParaKmeshWorld(nkstot, nspin);
 }
 
-// Temporary bridge: construct a bgroup-domain ParaBgroupWorld from the old
-// globals. Delete this file once ParaCollection is wired into driver init.
-ParaBgroupWorld make_bgroup_world()
+// Temporary bridge: construct a bdiff_ksame-domain ParaBdiffKsameWorld from
+// the old globals. Delete this file once ParaCollection is wired into driver init.
+ParaBdiffKsameWorld make_bdiff_ksame_world()
 {
 #ifdef __MPI
     int mpi_initialized = 0;
@@ -73,10 +73,10 @@ ParaBgroupWorld make_bgroup_world()
     {
         int nbndgroup = 1;
         MPI_Comm_size(BP_WORLD, &nbndgroup);
-        return ParaBgroupWorld(INT_BGROUP, BP_WORLD, nbndgroup);
+        return ParaBdiffKsameWorld(INT_BGROUP, BP_WORLD, nbndgroup);
     }
 #endif
-    return ParaBgroupWorld();
+    return ParaBdiffKsameWorld();
 }
 
 } // namespace Parallel

source/source_base/module_parallel/para_bridge.h

@@ -1,7 +1,7 @@
 #ifndef PARA_BRIDGE_H
 #define PARA_BRIDGE_H
 
-#include "para_bgroup_world.h"
+#include "para_bdiff_ksame_world.h"
 #include "para_kmesh_world.h"
 #include "para_world.h"
 
@@ -45,14 +45,15 @@ ParaKmeshWorld make_kmesh_world(int nkstot, int nspin);
 ParaKmeshWorld make_kmesh_world();
 
 /**
- * @brief Temporary bridge: construct a bgroup-domain ParaBgroupWorld from
- * the old globals INT_BGROUP / BP_WORLD (MPI) or as a serial domain.
+ * @brief Temporary bridge: construct a bdiff_ksame-domain
+ * ParaBdiffKsameWorld from the old globals INT_BGROUP / BP_WORLD (MPI) or
+ * as a serial domain.
  *
  * Falls back to a serial single-band-group domain when MPI is not
  * initialized or the pool layout has not been set up yet (e.g. unit
  * tests), so that no MPI call is made on an unset communicator.
  */
-ParaBgroupWorld make_bgroup_world();
+ParaBdiffKsameWorld make_bdiff_ksame_world();
 
 } // namespace Parallel
 

source/source_base/module_parallel/para_kmesh_world.h

@@ -19,7 +19,7 @@ namespace Parallel
  * The k-pool split (kpar) is independent of bndpar: the domain knows
  * nothing about band groups. Reductions that must span both dimensions
  * (e.g. the total electron count under BPCG) therefore combine
- * ParaBgroupWorld::reduce_across_bgroups (band dimension, run FIRST)
+ * ParaBdiffKsameWorld::reduce_across_bdiff_ksame (band dimension, run FIRST)
  * with reduce_across_pools (k dimension, run SECOND).
  *
  * In serial builds all operations degenerate to single-pool behavior.
@@ -117,7 +117,7 @@ class ParaKmeshWorld : public ParaWorld
      *
      * Precondition: with band parallelism (bndpar > 1) the caller must
      * first combine the band-group partial sums (e.g.
-     * ParaBgroupWorld::reduce_across_bgroups) so that every process of a
+     * ParaBdiffKsameWorld::reduce_across_bdiff_ksame) so that every process of a
      * k-pool holds one complete per-pool partial sum.
      *
      * No-op when kpar() <= 1.

source/source_base/module_parallel/test/CMakeLists.txt

@@ -30,8 +30,8 @@ AddTest(
 )
 
 AddTest(
-  TARGET MODULE_BASE_para_bgroup_world
-  SOURCES para_bgroup_world_test.cpp ../para_bgroup_world.cpp ../para_world.cpp
+  TARGET MODULE_BASE_para_bdiff_ksame_world
+  SOURCES para_bdiff_ksame_world_test.cpp ../para_bdiff_ksame_world.cpp ../para_world.cpp
 )
 
 AddTest(
@@ -80,7 +80,7 @@ target_compile_definitions(MODULE_BASE_para_setup_mpi PRIVATE __MPI)
 # Built with add_executable (not AddTest) so that no direct-run CTest entry is
 # created; the binary is only exercised through mpirun by the .sh test below,
 # matching the multi-process requirement of these cases.
-add_executable(MODULE_BASE_para_kmesh_world_mpi test_para_kmesh_world_mpi.cpp ../para_bgroup_world.cpp ../para_kmesh_world.cpp ../para_world.cpp)
+add_executable(MODULE_BASE_para_kmesh_world_mpi test_para_kmesh_world_mpi.cpp ../para_bdiff_ksame_world.cpp ../para_kmesh_world.cpp ../para_world.cpp)
 target_link_libraries(MODULE_BASE_para_kmesh_world_mpi PRIVATE MPI::MPI_CXX GTest::gtest GTest::gtest_main abacus::linalg_libs)
 target_compile_definitions(MODULE_BASE_para_kmesh_world_mpi PRIVATE __MPI)
 

…parallel/test/para_bgroup_world_test.cpp …lel/test/para_bdiff_ksame_world_test.cppsource/source_base/module_parallel/test/para_bgroup_world_test.cpp renamed to source/source_base/module_parallel/test/para_bdiff_ksame_world_test.cpp source/source_base/module_parallel/test/para_bgroup_world_test.cpp renamed to source/source_base/module_parallel/test/para_bdiff_ksame_world_test.cpp

@@ -1,10 +1,10 @@
 #include "gtest/gtest.h"
 
-#include "../para_bgroup_world.h"
+#include "../para_bdiff_ksame_world.h"
 
-TEST(ParaBgroupWorldTest, SerialMode)
+TEST(ParaBdiffKsameWorldTest, SerialMode)
 {
-    const Parallel::ParaBgroupWorld world;
+    const Parallel::ParaBdiffKsameWorld world;
     EXPECT_EQ(world.tag(), "bdiff_ksame");
     EXPECT_EQ(world.my_bndgroup(), 0);
     EXPECT_EQ(world.nbndgroup(), 1);
@@ -13,9 +13,9 @@ TEST(ParaBgroupWorldTest, SerialMode)
     EXPECT_TRUE(world.valid());
 }
 
-TEST(ParaBgroupWorldTest, AliasesMatchBase)
+TEST(ParaBdiffKsameWorldTest, AliasesMatchBase)
 {
-    const Parallel::ParaBgroupWorld world;
+    const Parallel::ParaBdiffKsameWorld world;
     EXPECT_EQ(world.rank_in_bpgroup(), world.rank());
     EXPECT_EQ(world.nproc_in_bndgroup(), world.size());
 }

source/source_base/module_parallel/test/test_para_kmesh_world_mpi.cpp

@@ -1,12 +1,12 @@
 #include "gtest/gtest.h"
 
-#include "../para_bgroup_world.h"
+#include "../para_bdiff_ksame_world.h"
 #include "../para_kmesh_world.h"
 
 // Run with: mpirun -np 4 ./MODULE_BASE_para_kmesh_world_mpi
 //
 // The sum reduction protocol has two layers:
-//   1. ParaBgroupWorld::reduce_across_bgroups  (band dimension, BPCG shards)
+//   1. ParaBdiffKsameWorld::reduce_across_bdiff_ksame (band dimension, BPCG shards)
 //   2. ParaKmeshWorld::reduce_across_pools      (k dimension, one
 //      contribution per k-pool: the first rank of each k-pool injects the
 //      partial sum, everyone else injects zero)
@@ -26,12 +26,12 @@ TEST(ParaKmeshWorldMpiTest, ReduceAcrossBandGroupsBndpar2)
     // which links the same rank position of every band group.
     MPI_Comm bp_world = MPI_COMM_NULL;
     MPI_Comm_split(MPI_COMM_WORLD, myrank % 2, myrank / 2, &bp_world);
-    Parallel::ParaBgroupWorld bgroup(MPI_COMM_WORLD, bp_world, 2);
+    Parallel::ParaBdiffKsameWorld bdiff(MPI_COMM_WORLD, bp_world, 2);
 
     // Each band group holds a partial occupation sum of 14 (28 electrons
     // split into two band windows).
     double sumk = 14.0;
-    bgroup.reduce_across_bgroups(sumk);
+    bdiff.reduce_across_bdiff_ksame(sumk);
     EXPECT_DOUBLE_EQ(sumk, 28.0);
 
     // max/min stay world-wide (idempotent) and must span the band groups
@@ -114,7 +114,7 @@ TEST(ParaKmeshWorldMpiTest, SinglePoolIsNoOp)
     ASSERT_EQ(nprocs, 4);
 
     // kpar == 1: the sum reduction must be a no-op regardless of the
-    // world size (the band dimension is handled by ParaBgroupWorld).
+    // world size (the band dimension is handled by ParaBdiffKsameWorld).
     Parallel::ParaKmeshWorld kmesh(MPI_COMM_WORLD, 1, 0, 0, 1);
     double sumk = 42.0;
     kmesh.reduce_across_pools(sumk);