Fixes to the processor topology code. Now does split into 4x4x4 on 64procs

(this was thrown off by floating-point to integer conversion errors before),
and also deals correctly with cases where one of the dimensions decomposes
into a large prime (this used to lead to, e.g., 62=2*1*31 rather than 1*2*31).

Tom


git-svn-id: http://svn.cactuscode.org/arrangements/CactusPUGH/PUGH/trunk@302 b61c5cb5-eaca-4651-9a7a-d64986f99364

1 files changed, 160 insertions, 10 deletions

diff --git a/src/SetupPGV.c b/src/SetupPGV.c
index 327c44a..e9c160f 100644
--- a/src/SetupPGV.c
+++ b/src/SetupPGV.c
@@ -24,9 +24,29 @@ static char *rcsid = "$Header$";
 CCTK_FILEVERSION(CactusPUGH_PUGH_SetupPGV_c)
 
 
-/* Prototypes */
+/********************************************************************
+ *********************     Local Data Types   ***********************
+ ********************************************************************/
 
+/********************************************************************
+ ********************* Local Routine Prototypes *********************
+ ********************************************************************/
 
+static int PUGH_IntegerRoot(int number, int invpower);
+
+static int IntSort(const void *a, const void *b);
+
+/********************************************************************
+ ********************* Other Routine Prototypes *********************
+ ********************************************************************/
+
+/********************************************************************
+ *********************     Local Data   *****************************
+ ********************************************************************/
+
+/********************************************************************
+ *********************     External Routines   **********************
+ ********************************************************************/
 
  /*@@
    @routine    PUGH_SetupPGExtras
@@ -261,7 +281,11 @@ void PUGH_DestroyConnectivity(pConnectivity **conn)
    @calls     
    @calledby   
    @history 
- 
+   @hdate Tue Jan 30 17:04:50 2001 @hauthor Tom Goodale
+   @hdesc Added call to integer root function and qsort to
+          avoid problems with real to integer conversions and
+          demonstrable failure of the algorithm when dealing
+          with large prime factors. 
    @endhistory 
 
 @@*/
@@ -312,26 +336,51 @@ int PUGH_GenerateTopology(int dim, int total_procs, int *nprocs)
      * in the highest dimension.
      */
 
+    int *working;
+    int root;
+    int place;
+
+    root = free_dims;
+    working = (int *)calloc(free_dims,sizeof(int));
 #ifdef DEBUG_PUGH
     printf("Processor topology for dimension %d\n",dim);
 #endif
 
-    for(i = 0; i < dim; i++)
+
+    for(i = 0; i < free_dims  ; i++)
     {
-      if(nprocs[i]==0)
-      {
-        nprocs[i] = pow(free_procs, 1.0/free_dims);
+      working[i] = PUGH_IntegerRoot(free_procs, root);
+      
+      while(free_procs % working[i]) working[i]--;
 
 #ifdef DEBUG_PUGH
-        printf(" nprocs[%d] = %d\n",i,nprocs[i]);
+      printf(" working[%d] = %d\n",i,working[i]);
 #endif
+      free_procs /= working[i];
+      root--;
+    }
 
-        while(free_procs % nprocs[i]) nprocs[i]--;
+    
+    /* The above doesn't necessarily sort them properly 
+     * e.g. if one of the factors is a prime then the
+     * above will sort the 1 before the prime.
+     */
+    qsort(working,free_dims,sizeof(int),IntSort);
 
-        free_procs /= nprocs[i];
-        free_dims--;
+    for(i = 0,place=0; i < dim ; i++)
+    {
+      if(nprocs[i] <= 0)
+      {
+        nprocs[i] = working[place];
+        place++;
       }
+
+#ifdef DEBUG_PUGH
+      printf(" nprocs[%d] = %d\n",i,nprocs[i]);
+#endif
     }
+
+    free(working);
   }
 
   return retval;
@@ -1532,3 +1581,104 @@ void PUGH_DestroyGArray(pGA **GA)
     *GA = NULL;
   }
 }
+
+/********************************************************************
+ *********************     Local Routines   *************************
+ ********************************************************************/
+
+ /*@@
+   @routine    PUGH_IntegerRoot
+   @date       Tue Jan 30 17:06:21 2001
+   @author     Tom Goodale
+   @desc 
+   Generate the highest integer below a given integer root of an integer.
+   @enddesc 
+   @calls     
+   @calledby   
+   @history 
+ 
+   @endhistory 
+   @var     number
+   @vdesc   The number to take the root of
+   @vtype   int
+   @vio     in
+   @vcomment 
+ 
+   @endvar 
+   @var     invpower
+   @vdesc   The root to take
+   @vtype   int
+   @vio     in
+   @vcomment 
+ 
+   @endvar 
+
+   @returntype int
+   @returndesc
+   The highest integer below the desired root.
+   @endreturndesc
+@@*/
+static int PUGH_IntegerRoot(int number, int invpower)
+{
+  int i;
+  int tmp;
+  int root;
+
+  for(root = 1; root <= number; root++)
+  {
+    for(i=1, tmp=root; i < invpower; i++, tmp*=root);
+
+    if(tmp > number)
+    {
+      root--;
+      break;
+    }
+  }
+  
+  return root;
+}
+
+ /*@@
+   @routine    IntSort
+   @date       Tue Jan 30 17:08:47 2001
+   @author     Tom Goodale
+   @desc 
+   Sorts two integers for the qsort routine.
+   @enddesc 
+   @calls     
+   @calledby   
+   @history 
+ 
+   @endhistory 
+   @var     a
+   @vdesc   First variable to compare
+   @vtype   const void *
+   @vio     in
+   @vcomment 
+   This should be a pointer to an integer.
+   @endvar 
+   @var     b
+   @vdesc   Second variable to compare
+   @vtype   const void *
+   @vio     in
+   @vcomment 
+   This should be a pointer to an integer.
+   @endvar 
+
+   @returntype int
+   @returndesc
+   -ve if b is greater than a.
+   +ve if a is greater than b.
+   0   if a is equal to b.
+   @endreturndesc
+@@*/
+static int IntSort(const void *a, const void *b)
+{
+  int reala,realb;
+
+  reala = *(int *)a;
+  realb = *(int *)b;
+
+  return reala - realb;
+
+}