[gnumeric] Regression: avoid repeated identical SUMSQ calls.

[Morten Welinder <mortenw src gnome org>]

commit e830dfc66966819fda7fc6b3ee36221c926c1df1
Author: Morten Welinder <terra gnome org>
Date:   Sun Jan 20 12:48:44 2013 -0500

    Regression: avoid repeated identical SUMSQ calls.

 NEWS                       |    1 +
 src/tools/ChangeLog        |    2 ++
 src/tools/analysis-tools.c |   17 ++---------------
 3 files changed, 5 insertions(+), 15 deletions(-)
---
diff --git a/NEWS b/NEWS
index fbdfbc5..b1e4830 100644
--- a/NEWS
+++ b/NEWS
@@ -27,6 +27,7 @@ Morten:
 	* Fix text import crash.
 	* Add LEVERAGE function for regression tool.  [#691913]
 	* Clean up matrix code.
+	* Speed up regressions.  [#691984]
 
 --------------------------------------------------------------------------
 Gnumeric 1.12.0
diff --git a/src/tools/ChangeLog b/src/tools/ChangeLog
index 7ce79b6..165bf66 100644
--- a/src/tools/ChangeLog
+++ b/src/tools/ChangeLog
@@ -2,6 +2,8 @@
 
 	* analysis-tools.c (analysis_tool_regression_engine_run): Simplify
 	using new LEVERAGE function.
+	(analysis_tool_regression_engine_run): Don't create zillions of
+	identical SUMSQ calls computing a value we already have.
 
 2012-12-18  Morten Welinder <terra gnome org>
 
diff --git a/src/tools/analysis-tools.c b/src/tools/analysis-tools.c
index 16aae31..05580d8 100644
--- a/src/tools/analysis-tools.c
+++ b/src/tools/analysis-tools.c
@@ -2880,9 +2880,7 @@ analysis_tool_regression_engine_run (data_analysis_output_t *dao,
 	GnmFunc *fd_cell = NULL;
 	GnmFunc *fd_offset = NULL;
 	GnmFunc *fd_sumproduct = NULL;
-	GnmFunc *fd_mmult = NULL;
 	GnmFunc *fd_leverage = NULL;
-	GnmFunc *fd_sumsq = NULL;
 
 	char const *str = ((info->group_by == GROUPED_BY_ROW) ? "row" : "col");
 	char const *label = ((info->group_by == GROUPED_BY_ROW) ? _("Row")
@@ -2896,9 +2894,7 @@ analysis_tool_regression_engine_run (data_analysis_output_t *dao,
 	}
 	if (info->residual) {
 		fd_sumproduct  = analysis_tool_get_function ("SUMPRODUCT", dao);
-		fd_mmult  = analysis_tool_get_function ("MMULT", dao);
 		fd_leverage = analysis_tool_get_function ("LEVERAGE", dao);
-		fd_sumsq  = analysis_tool_get_function ("SUMSQ", dao);
 	}
 
 	cb_adjust_areas (val_1, NULL);
@@ -3345,11 +3341,7 @@ analysis_tool_regression_engine_run (data_analysis_output_t *dao,
 				gnm_expr_new_funcall1
 				(fd_leverage, expr_X);
 			GnmExpr const *expr_var =
-				gnm_expr_new_binary
-				(gnm_expr_new_funcall1
-				 (fd_sumsq, dao_get_rangeref (dao, xdim + 3, 1, xdim + 3, n_obs)),
-				 GNM_EXPR_OP_DIV,
-				 dao_get_cellref (dao, 1, - 6 - xdim));
+				dao_get_cellref (dao, 3, - 6 - xdim);
 			GnmExpr const *expr_int_stud =
 				gnm_expr_new_binary
 				(make_cellref (-2, 0),
@@ -3368,8 +3360,7 @@ analysis_tool_regression_engine_run (data_analysis_output_t *dao,
 
 			expr_var = gnm_expr_new_binary
 				(gnm_expr_new_binary
-				 (gnm_expr_new_funcall1
-				  (fd_sumsq, dao_get_rangeref (dao, xdim + 3, 1, xdim + 3, n_obs)),
+				 (dao_get_cellref (dao, 2, - 6 - xdim),
 				  GNM_EXPR_OP_SUB,
 				  gnm_expr_new_binary
 				  (make_cellref (-3, 0),
@@ -3437,12 +3428,8 @@ analysis_tool_regression_engine_run (data_analysis_output_t *dao,
 		gnm_func_unref (fd_offset);
 	if (fd_sumproduct != NULL)
 		gnm_func_unref (fd_sumproduct);
-	if (fd_mmult != NULL)
-		gnm_func_unref (fd_mmult);
 	if (fd_leverage != NULL)
 		gnm_func_unref (fd_leverage);
-	if (fd_sumsq != NULL)
-		gnm_func_unref (fd_sumsq);
 
 	dao_redraw_respan (dao);