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authorko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2007-09-28 10:18:53 +0000
committerko1 <ko1@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>2007-09-28 10:18:53 +0000
commit30b2cb380e0a8f777a2fc2d736c2ccddf3362fcd (patch)
tree715a72c59e797ee8ca71ce8870db38bf68ed3fd1 /benchmark/bm_so_spectralnorm.rb
parent335fe1ee7bf51534c5f2abd0f359e86721307335 (diff)
* benchmark/driver.rb: fix notations.
* benchmark/bm_loop_whileloop.rb: ditto. * benchmark/bm_loop_whileloop2.rb: ditto. * benchmark/bm_app_uri.rb: added. * benchmark/bm_vm1_ivar_set.rb: ditto. * benchmark/bm_so_binary_trees.rb: added from Computer Language Benchmarks Game (http://shootout.alioth.debian.org/). * benchmark/bm_so_fannkuch.rb: ditto. * benchmark/bm_so_mandelbrot.rb: ditto. * benchmark/bm_so_meteor_contest.rb: ditto. * benchmark/bm_so_nbody.rb: ditto. * benchmark/bm_so_nsieve.rb: ditto. * benchmark/bm_so_nsieve_bits.rb: ditto. * benchmark/bm_so_partial_sums.rb: ditto. * benchmark/bm_so_pidigits.rb: ditto. * benchmark/bm_so_spectralnorm.rb: ditto. git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@13548 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'benchmark/bm_so_spectralnorm.rb')
-rw-r--r--benchmark/bm_so_spectralnorm.rb50
1 files changed, 50 insertions, 0 deletions
diff --git a/benchmark/bm_so_spectralnorm.rb b/benchmark/bm_so_spectralnorm.rb
new file mode 100644
index 0000000..3617da5
--- /dev/null
+++ b/benchmark/bm_so_spectralnorm.rb
@@ -0,0 +1,50 @@
+# The Computer Language Shootout
+# http://shootout.alioth.debian.org/
+# Contributed by Sokolov Yura
+
+def eval_A(i,j)
+ return 1.0/((i+j)*(i+j+1)/2+i+1)
+end
+
+def eval_A_times_u(u)
+ v, i = nil, nil
+ (0..u.length-1).collect { |i|
+ v = 0
+ for j in 0..u.length-1
+ v += eval_A(i,j)*u[j]
+ end
+ v
+ }
+end
+
+def eval_At_times_u(u)
+ v, i = nil, nil
+ (0..u.length-1).collect{|i|
+ v = 0
+ for j in 0..u.length-1
+ v += eval_A(j,i)*u[j]
+ end
+ v
+ }
+end
+
+def eval_AtA_times_u(u)
+ return eval_At_times_u(eval_A_times_u(u))
+end
+
+n = 500 # ARGV[0].to_i
+
+u=[1]*n
+for i in 1..10
+ v=eval_AtA_times_u(u)
+ u=eval_AtA_times_u(v)
+end
+vBv=0
+vv=0
+for i in 0..n-1
+ vBv += u[i]*v[i]
+ vv += v[i]*v[i]
+end
+
+str = "%0.9f" % (Math.sqrt(vBv/vv)), "\n"
+# print str