X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=lib%2Flinreg%2Fsweep.c;h=62dda200701ceda43e4040e3128b1b8121b9e279;hb=f2d4cc6e7a4d5948a2c0cf70883347000a79a2b0;hp=0f8c223c7aa5b2e55c8619fba8be93fff679abb4;hpb=1e60b6097b6ad896787a0aa831d82fd98b946dd5;p=pspp

diff --git a/lib/linreg/sweep.c b/lib/linreg/sweep.c
index 0f8c223c7a..62dda20070 100644
--- a/lib/linreg/sweep.c
+++ b/lib/linreg/sweep.c
@@ -1,5 +1,5 @@
 /* PSPP - a program for statistical analysis.
-   Copyright (C) 2005, 2009 Free Software Foundation, Inc.
+   Copyright (C) 2005, 2009, 2011 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -69,19 +69,16 @@
 int
 reg_sweep (gsl_matrix * A, int last_col)
 {
-  if (A == NULL)
-    return GSL_EFAULT;
-
-  if (A->size1 != A->size2)
-    return GSL_ENOTSQR;
-
-  double sweep_element;
-  double tmp;
   int i;
   int j;
   int k;
   gsl_matrix *B;
 
+  if (A == NULL)
+    return GSL_EFAULT;
+
+  if (A->size1 != A->size2)
+    return GSL_ENOTSQR;
 
   assert (last_col < A->size1);
   gsl_matrix_swap_rows (A, A->size1 - 1, last_col);
@@ -90,11 +87,10 @@ reg_sweep (gsl_matrix * A, int last_col)
   B = gsl_matrix_alloc (A->size1, A->size2);
   for (k = 0; k < (A->size1 - 1); k++)
     {
-      sweep_element = gsl_matrix_get (A, k, k);
+      const double sweep_element = gsl_matrix_get (A, k, k);
       if (fabs (sweep_element) > GSL_DBL_MIN)
 	{
-	  tmp = -1.0 / sweep_element;
-	  gsl_matrix_set (B, k, k, tmp);
+	  gsl_matrix_set (B, k, k, -1.0 / sweep_element);
 	  /*
 	    Rows before current row k.
 	  */
@@ -102,28 +98,25 @@ reg_sweep (gsl_matrix * A, int last_col)
 	    {
 	      for (j = i; j < A->size2; j++)
 		{
-		  /*
-		    Use only the upper triangle of A.
-		  */
+		  /* Use only the upper triangle of A. */
+		  double tmp;
 		  if (j < k)
 		    {
 		      tmp = gsl_matrix_get (A, i, j) -
 			gsl_matrix_get (A, i, k)
 			* gsl_matrix_get (A, j, k) / sweep_element;
-		      gsl_matrix_set (B, i, j, tmp);
 		    }
 		  else if (j > k)
 		    {
 		      tmp = gsl_matrix_get (A, i, j) -
 			gsl_matrix_get (A, i, k)
 			* gsl_matrix_get (A, k, j) / sweep_element;
-		      gsl_matrix_set (B, i, j, tmp);
 		    }
 		  else
 		    {
 		      tmp = gsl_matrix_get (A, i, k) / sweep_element;
-		      gsl_matrix_set (B, i, j, tmp);
 		    }
+		  gsl_matrix_set (B, i, j, tmp);
 		}
 	    }
 	  /*
@@ -131,7 +124,7 @@ reg_sweep (gsl_matrix * A, int last_col)
 	  */
 	  for (j = k + 1; j < A->size1; j++)
 	    {
-	      tmp = gsl_matrix_get (A, k, j) / sweep_element;
+	      double tmp = gsl_matrix_get (A, k, j) / sweep_element;
 	      gsl_matrix_set (B, k, j, tmp);
 	    }
 	  /*
@@ -141,18 +134,14 @@ reg_sweep (gsl_matrix * A, int last_col)
 	    {
 	      for (j = i; j < A->size2; j++)
 		{
-		  tmp = gsl_matrix_get (A, i, j) -
+		  double tmp = gsl_matrix_get (A, i, j) -
 		    gsl_matrix_get (A, k, i)
 		    * gsl_matrix_get (A, k, j) / sweep_element;
 		  gsl_matrix_set (B, i, j, tmp);
 		}
 	    }
 	}
-      for (i = 0; i < A->size1; i++)
-	for (j = i; j < A->size2; j++)
-	  {
-	    gsl_matrix_set (A, i, j, gsl_matrix_get (B, i, j));
-	  }
+      gsl_matrix_memcpy (A, B);
     }
   gsl_matrix_free (B);