From fcbf63e62c627deae76c1b8cb8c0876c536ed811 Mon Sep 17 00:00:00 2001
From: Jari Vetoniemi <jari.vetoniemi@indooratlas.com>
Date: Mon, 16 Mar 2020 18:49:26 +0900
Subject: Fresh start

---
 jni/ruby/ext/bigdecimal/sample/linear.rb | 72 ++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 jni/ruby/ext/bigdecimal/sample/linear.rb

(limited to 'jni/ruby/ext/bigdecimal/sample/linear.rb')

diff --git a/jni/ruby/ext/bigdecimal/sample/linear.rb b/jni/ruby/ext/bigdecimal/sample/linear.rb
new file mode 100644
index 0000000..a33255f
--- /dev/null
+++ b/jni/ruby/ext/bigdecimal/sample/linear.rb
@@ -0,0 +1,72 @@
+#!/usr/local/bin/ruby
+
+#
+# linear.rb
+#
+# Solves linear equation system(A*x = b) by LU decomposition method.
+#  where  A is a coefficient matrix,x is an answer vector,b is a constant vector.
+#
+# USAGE:
+#   ruby linear.rb [input file solved]
+#
+
+# :stopdoc:
+require "bigdecimal"
+require "bigdecimal/ludcmp"
+
+#
+# NOTE:
+#   Change following BigDecimal.limit() if needed.
+BigDecimal.limit(100)
+#
+
+include LUSolve
+def rd_order(na)
+   printf("Number of equations ?") if(na <= 0)
+   n = ARGF.gets().to_i
+end
+
+na   = ARGV.size
+zero = BigDecimal.new("0.0")
+one  = BigDecimal.new("1.0")
+
+while (n=rd_order(na))>0
+  a = []
+  as= []
+  b = []
+  if na <= 0
+     # Read data from console.
+     printf("\nEnter coefficient matrix element A[i,j]\n");
+     for i in 0...n do
+       for j in 0...n do
+         printf("A[%d,%d]? ",i,j); s = ARGF.gets
+         a  << BigDecimal.new(s);
+         as << BigDecimal.new(s);
+       end
+       printf("Contatant vector element b[%d] ? ",i); b << BigDecimal.new(ARGF.gets);
+     end
+  else
+     # Read data from specified file.
+     printf("Coefficient matrix and constant vector.\n");
+     for i in 0...n do
+       s = ARGF.gets
+       printf("%d) %s",i,s)
+       s = s.split
+       for j in 0...n do
+         a  << BigDecimal.new(s[j]);
+         as << BigDecimal.new(s[j]);
+       end
+       b << BigDecimal.new(s[n]);
+     end
+  end
+  x = lusolve(a,b,ludecomp(a,n,zero,one),zero)
+  printf("Answer(x[i] & (A*x-b)[i]) follows\n")
+  for i in 0...n do
+     printf("x[%d]=%s ",i,x[i].to_s)
+     s = zero
+     for j in 0...n do
+       s = s + as[i*n+j]*x[j]
+     end
+     printf(" & %s\n",(s-b[i]).to_s)
+  end
+end
-- 
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