Iteration 0027 — 5840dac0d9f1 (accepted)

GitHub commit: 5840dac0d9f1 Published branch: fermilink-optimize/lammps-tip4p

Change summary

Inline TIP4P pair/PPPM cache-hit fast paths while keeping cache-miss reconstruction in dedicated out-of-line slow helpers

Acceptance rationale

Correctness passed and 70.984 beats incumbent 72.919 by 2.65%, clearing the 2% acceptance bar.

Guardrails & metrics

field	value
decision	ACCEPTED
correctness	ok
correctness mode	field_tolerances
hard reject	no
guardrail errors	0
incumbent commit	4cbc0fa85603
candidate commit	5840dac0d9f1
incumbent metric	72.919
candidate metric	70.984
baseline metric	94.717
Δ vs incumbent	+2.654% (lower-is-better sign)
changed files	src/KSPACE/pair_lj_cut_tip4p_long.cpp, src/KSPACE/pair_lj_cut_tip4p_long.h, src/KSPACE/pppm_tip4p.cpp, src/KSPACE/pppm_tip4p.h

Diffstat

src/KSPACE/pair_lj_cut_tip4p_long.cpp | 44 ++++++++++++++---------------------
src/KSPACE/pair_lj_cut_tip4p_long.h   | 17 +++++++++++++-
src/KSPACE/pppm_tip4p.cpp             |  8 +++----
src/KSPACE/pppm_tip4p.h               | 14 ++++++++++-
4 files changed, 49 insertions(+), 34 deletions(-)

Diff

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diff --git a/src/KSPACE/pair_lj_cut_tip4p_long.cpp b/src/KSPACE/pair_lj_cut_tip4p_long.cpp
index 7d6d4a8fa2..c79b0ac40f 100644
--- a/src/KSPACE/pair_lj_cut_tip4p_long.cpp
+++ b/src/KSPACE/pair_lj_cut_tip4p_long.cpp
@@ -514,36 +514,26 @@ void PairLJCutTIP4PLong::reset_tip4p_cache_stamps()

 /* ---------------------------------------------------------------------- */

-double *PairLJCutTIP4PLong::tip4p_site(int i, int &iH1, int &iH2, double **x, tagint *tag,
-                                       int *type)
+double *PairLJCutTIP4PLong::tip4p_site_slow(int i, int &iH1, int &iH2, double **x,
+                                            tagint *tag, int *type)
 {
   Tip4pSiteCache &cache = tip4p_cache[i];

-  if (cache.neigh_stamp != neigh_stamp) {
-    iH1 = atom->map(tag[i] + 1);
-    iH2 = atom->map(tag[i] + 2);
-    if (iH1 == -1 || iH2 == -1)
-      error->one(FLERR,"TIP4P hydrogen is missing");
-    if (type[iH1] != typeH || type[iH2] != typeH)
-      error->one(FLERR,"TIP4P hydrogen has incorrect atom type");
-
-    iH1 = domain->closest_image(i,iH1);
-    iH2 = domain->closest_image(i,iH2);
-    cache.iH1 = iH1;
-    cache.iH2 = iH2;
-    cache.neigh_stamp = neigh_stamp;
-    cache.site_stamp = 0;
-
-  } else {
-    iH1 = cache.iH1;
-    iH2 = cache.iH2;
-  }
-
-  if (cache.site_stamp != site_stamp) {
-    compute_newsite(x[i],x[iH1],x[iH2],cache.xM);
-    cache.site_stamp = site_stamp;
-  }
-
+  iH1 = atom->map(tag[i] + 1);
+  iH2 = atom->map(tag[i] + 2);
+  if (iH1 == -1 || iH2 == -1)
+    error->one(FLERR,"TIP4P hydrogen is missing");
+  if (type[iH1] != typeH || type[iH2] != typeH)
+    error->one(FLERR,"TIP4P hydrogen has incorrect atom type");
+
+  iH1 = domain->closest_image(i,iH1);
+  iH2 = domain->closest_image(i,iH2);
+  cache.iH1 = iH1;
+  cache.iH2 = iH2;
+  cache.neigh_stamp = neigh_stamp;
+
+  compute_newsite(x[i],x[iH1],x[iH2],cache.xM);
+  cache.site_stamp = site_stamp;
   return cache.xM;
 }

diff --git a/src/KSPACE/pair_lj_cut_tip4p_long.h b/src/KSPACE/pair_lj_cut_tip4p_long.h
index 233fbb0dcc..fc02aa2800 100644
--- a/src/KSPACE/pair_lj_cut_tip4p_long.h
+++ b/src/KSPACE/pair_lj_cut_tip4p_long.h
@@ -65,7 +65,22 @@ class PairLJCutTIP4PLong : public PairLJCutCoulLong {
               double, double);
   void grow_tip4p_cache();
   void reset_tip4p_cache_stamps();
-  double *tip4p_site(int, int &, int &, double **, tagint *, int *);
+  double *tip4p_site(int i, int &iH1, int &iH2, double **x, tagint *tag, int *type)
+  {
+    Tip4pSiteCache &cache = tip4p_cache[i];
+
+    if (cache.neigh_stamp != neigh_stamp) return tip4p_site_slow(i,iH1,iH2,x,tag,type);
+
+    iH1 = cache.iH1;
+    iH2 = cache.iH2;
+    if (cache.site_stamp != site_stamp) {
+      compute_newsite(x[i],x[iH1],x[iH2],cache.xM);
+      cache.site_stamp = site_stamp;
+    }
+
+    return cache.xM;
+  }
+  double *tip4p_site_slow(int, int &, int &, double **, tagint *, int *);
   void compute_newsite(double *, double *, double *, double *);
 };

diff --git a/src/KSPACE/pppm_tip4p.cpp b/src/KSPACE/pppm_tip4p.cpp
index 4ddee644a8..b8bf5f351f 100644
--- a/src/KSPACE/pppm_tip4p.cpp
+++ b/src/KSPACE/pppm_tip4p.cpp
@@ -108,15 +108,13 @@ void PPPMTIP4P::reset_tip4p_cache_stamps()

 /* ---------------------------------------------------------------------- */

-void PPPMTIP4P::find_M_cached(int i, int &iH1, int &iH2, double *&xM)
+void PPPMTIP4P::find_M_cached_slow(int i, int &iH1, int &iH2, double *&xM)
 {
   if (atom->nmax > tip4p_cache_nmax) grow_tip4p_cache();

   Tip4pCache &cache = tip4p_cache[i];
-  if (cache.stamp != tip4p_cache_stamp) {
-    find_M(i,cache.iH1,cache.iH2,cache.xM);
-    cache.stamp = tip4p_cache_stamp;
-  }
+  find_M(i,cache.iH1,cache.iH2,cache.xM);
+  cache.stamp = tip4p_cache_stamp;

   iH1 = cache.iH1;
   iH2 = cache.iH2;
diff --git a/src/KSPACE/pppm_tip4p.h b/src/KSPACE/pppm_tip4p.h
index d907f96dd3..5ee607541f 100644
--- a/src/KSPACE/pppm_tip4p.h
+++ b/src/KSPACE/pppm_tip4p.h
@@ -56,7 +56,19 @@ class PPPMTIP4P : public PPPM {

   void grow_tip4p_cache();
   void reset_tip4p_cache_stamps();
-  void find_M_cached(int, int &, int &, double *&);
+  void find_M_cached(int i, int &iH1, int &iH2, double *&xM)
+  {
+    Tip4pCache &cache = tip4p_cache[i];
+    if (cache.stamp != tip4p_cache_stamp) {
+      find_M_cached_slow(i,iH1,iH2,xM);
+      return;
+    }
+
+    iH1 = cache.iH1;
+    iH2 = cache.iH2;
+    xM = cache.xM;
+  }
+  void find_M_cached_slow(int, int &, int &, double *&);
   void find_M(int, int &, int &, double *);
 };