diff options
author | shyouhei <shyouhei@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2007-08-15 20:57:30 +0000 |
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committer | shyouhei <shyouhei@b2dd03c8-39d4-4d8f-98ff-823fe69b080e> | 2007-08-15 20:57:30 +0000 |
commit | 54ec1c4fe81672ca66f327ef6ae170f458cd79e5 (patch) | |
tree | 45a752c60a9a08d681a792b70f43c89903b638a2 /ruby_1_8_5/ext/bigdecimal/lib/bigdecimal/ludcmp.rb | |
parent | d464704f111d211c1f1ff9ef23ef1d755054be00 (diff) |
sorry. I made wrong tags.v1_8_5_54
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/tags/v1_8_5_54@13009 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Diffstat (limited to 'ruby_1_8_5/ext/bigdecimal/lib/bigdecimal/ludcmp.rb')
-rw-r--r-- | ruby_1_8_5/ext/bigdecimal/lib/bigdecimal/ludcmp.rb | 84 |
1 files changed, 0 insertions, 84 deletions
diff --git a/ruby_1_8_5/ext/bigdecimal/lib/bigdecimal/ludcmp.rb b/ruby_1_8_5/ext/bigdecimal/lib/bigdecimal/ludcmp.rb deleted file mode 100644 index 8f4888725e..0000000000 --- a/ruby_1_8_5/ext/bigdecimal/lib/bigdecimal/ludcmp.rb +++ /dev/null @@ -1,84 +0,0 @@ -# -# Solves a*x = b for x, using LU decomposition. -# -module LUSolve - # Performs LU decomposition of the n by n matrix a. - def ludecomp(a,n,zero=0,one=1) - prec = BigDecimal.limit(nil) - ps = [] - scales = [] - for i in 0...n do # pick up largest(abs. val.) element in each row. - ps <<= i - nrmrow = zero - ixn = i*n - for j in 0...n do - biggst = a[ixn+j].abs - nrmrow = biggst if biggst>nrmrow - end - if nrmrow>zero then - scales <<= one.div(nrmrow,prec) - else - raise "Singular matrix" - end - end - n1 = n - 1 - for k in 0...n1 do # Gaussian elimination with partial pivoting. - biggst = zero; - for i in k...n do - size = a[ps[i]*n+k].abs*scales[ps[i]] - if size>biggst then - biggst = size - pividx = i - end - end - raise "Singular matrix" if biggst<=zero - if pividx!=k then - j = ps[k] - ps[k] = ps[pividx] - ps[pividx] = j - end - pivot = a[ps[k]*n+k] - for i in (k+1)...n do - psin = ps[i]*n - a[psin+k] = mult = a[psin+k].div(pivot,prec) - if mult!=zero then - pskn = ps[k]*n - for j in (k+1)...n do - a[psin+j] -= mult.mult(a[pskn+j],prec) - end - end - end - end - raise "Singular matrix" if a[ps[n1]*n+n1] == zero - ps - end - - # Solves a*x = b for x, using LU decomposition. - # - # a is a matrix, b is a constant vector, x is the solution vector. - # - # ps is the pivot, a vector which indicates the permutation of rows performed - # during LU decomposition. - def lusolve(a,b,ps,zero=0.0) - prec = BigDecimal.limit(nil) - n = ps.size - x = [] - for i in 0...n do - dot = zero - psin = ps[i]*n - for j in 0...i do - dot = a[psin+j].mult(x[j],prec) + dot - end - x <<= b[ps[i]] - dot - end - (n-1).downto(0) do |i| - dot = zero - psin = ps[i]*n - for j in (i+1)...n do - dot = a[psin+j].mult(x[j],prec) + dot - end - x[i] = (x[i]-dot).div(a[psin+i],prec) - end - x - end -end |