From 27613921c7e2bcd51cad6e1430de52b677e811c7 Mon Sep 17 00:00:00 2001
From: Jonathan Lambrechts <jonathan.lambrechts@uclouvain.be>
Date: Tue, 19 Oct 2010 11:00:05 +0000
Subject: [PATCH] Solver : linearSystemCSR : faster access to matrix entries
when sorted (10 times faster for a typical CG matrix on p6 tet)
---
Solver/linearSystemCSR.h | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/Solver/linearSystemCSR.h b/Solver/linearSystemCSR.h
index 9309816813..6387315df9 100644
--- a/Solver/linearSystemCSR.h
+++ b/Solver/linearSystemCSR.h
@@ -55,7 +55,30 @@ class linearSystemCSR : public linearSystem<scalar> {
INDEX_TYPE position = jptr[il];
- if(something[il]) {
+ if (sorted) { // use bisection and direct adressing if sorted
+ int p0 = jptr[il];
+ int p1 = jptr[il+1];
+ while (p1-p0 > 20) {
+ position = ((p0+p1)/2);
+ if (ai[position] > ic)
+ p1 = position;
+ else if (ai[position] < ic)
+ p0 = position + 1;
+ else {
+ a[position] += val;
+ return;
+ }
+ }
+ for (position = p0; position < p1; position++) {
+ if (ai[position] >= ic) {
+ if (ai[position] == ic){
+ a[position] += val;
+ return;
+ }
+ break;
+ }
+ }
+ } else if(something[il]) {
while(1){
if(ai[position] == ic){
a[position] += val;
--
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