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#include "lll.h"
/*double lensq(vektor_f *a)
{
vektor_f A1=(*a* *a);
return A1.sum();
}
*/
int down(double f)
{
if(f>=0)return int(f);
return int(f-1);
}
void calcmy(IntegerMatrix const &b, FloatMatrix &my, Vektor<double> &B)
{
FloatMatrix bs=integerToFloatMatrix(b);
for(int k=0;k<b.getHeight();k++)
{
bs[k]=b[k];
for(int j=0;j<k;j++)
{
if(B[j]==0)
my[k][j]=0;
else
my[k][j]=dot(Vektor<double>(b[k]),bs[j])/B[j];
bs[k]=bs[k]-my[k][j]*bs[j];
}
B[k]=dot(bs[k],bs[k]);
}
}
/*void calclambda(basis_i b, basis_f &lambda)
{
for(int k=0;k<b.size();k++)
{
for(int j=0;j<=k;j++)
{
double u=dot(b[k],b[j]);
for(int i=0;i<j;i++)
{
if(i-1==-1)
{
u=lambda[i][i]*u-lambda[k][i]*lambda[j][i];
}
else
{
if(lambda[i-1][i-1]!=0)
{
u=lambda[i][i]*u-lambda[k][i]*lambda[j][i];
u/=lambda[i-1][i-1];
}
}
}
lambda[k][j]=u;
}
}
}*/
IntegerMatrix mlll(IntegerMatrix &b, IntegerMatrix *inverseTransposedM)
{
int k=1;
int n=b.getHeight();// number of generators
FloatMatrix my(n,n);//n*n
Vektor<double> B(n);
IntegerMatrix M=IntegerMatrix::identity(n);//n*n;
IntegerMatrix MInverseTransposed=M;
calcmy(b,my,B);
while(k<n)
{
//size reduction
for(int l=k-1;l>=0;l--)
{
// calclambda(b,lambda);
int q=down(my[k][l]+0.5);
if(q)
{
b[k]=b[k]-q*b[l];
M[k]=M[k]-q*M[l];
MInverseTransposed[l]+=q*MInverseTransposed[k];
calcmy(b,my,B);
}
}
// calcmy(b,my,B);
// calclambda(b,lambda);
//test Lovasz' condition
if(B[k]<(0.75-my[k][k-1]*my[k][k-1])*B[k-1])
{
Vektor<double> temp=b[k];b[k]=b[k-1];b[k-1]=temp;
Vektor<double> temp1=M[k];M[k]=M[k-1];M[k-1]=temp1;
temp1=MInverseTransposed[k];MInverseTransposed[k]=MInverseTransposed[k-1];MInverseTransposed[k-1]=temp1;
calcmy(b,my,B);
k--;
if(k<1)k=1;
}
else k++;
}
if(inverseTransposedM)*inverseTransposedM=MInverseTransposed;
return M;
}
/*int rank(basis_i B)
{
int n=B.size();
basis_i M=mlll(B);
int kerdim=0;
while((kerdim<B.size())&&(B[kerdim].iszero()))kerdim++;
return n-kerdim;
}
*/
IntegerMatrix latticeKernelOfTransposed(IntegerMatrix const &B)
{
IntegerMatrix B2=B;
IntegerMatrix M=mlll(B2);
int kerdim=0;
while((kerdim<B.getHeight())&&(B2[kerdim].isZero()))
kerdim++;
IntegerMatrix ret(kerdim,B.getHeight());
for(int i=0;i<kerdim;i++)
ret[i]=M[i];
// add asserts to check that lll reduction works correctly
return ret;
}
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