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