diff options
Diffstat (limited to 'ruby_1_8_5/ext/bigdecimal/sample/linear.rb')
-rw-r--r-- | ruby_1_8_5/ext/bigdecimal/sample/linear.rb | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/ruby_1_8_5/ext/bigdecimal/sample/linear.rb b/ruby_1_8_5/ext/bigdecimal/sample/linear.rb new file mode 100644 index 0000000000..88a62ffa71 --- /dev/null +++ b/ruby_1_8_5/ext/bigdecimal/sample/linear.rb @@ -0,0 +1,71 @@ +#!/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] +# + +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 |