quantum_matrix quantum_density_matrix( quantum_density_op *rho )
{
int i, j, k, l1, l2, dim = 1 << rho->reg->width;
quantum_matrix m;
if ( dim < 0 )
quantum_error( 3 );
m = quantum_new_matrix( dim, dim );
k = 0;
for ( ; k < rho->num; k++ )
{
quantum_reconstruct_hash( &rho->reg[ k ] );
i = 0;
for ( ; i < dim; i++ )
{
j = 0;
for ( ; j < dim; j++ )
{
l1 = quantum_get_state( i, rho->reg[ k ] );
l2 = quantum_get_state( j, rho->reg[ k ] );
if ( l1 >= 0 && l2 >= 0 )
{
m.t[ i + ( m.cols * j ) ] += rho->reg[ k ].node[ l2 ].amplitude * rho->prob[ k ] * quantum_conj( rho->reg[ k ].node[ l1 ].amplitude );
}
//j++;
}
//i++;
}
//k++;
}
return m;
}
quantum_matrix quantum_mmult( quantum_matrix A, quantum_matrix B )
{
int i, j, k;
quantum_matrix C;
if ( A.cols != B.rows )
quantum_error( 4 );
C = quantum_new_matrix( B.cols, A.rows );
i = 0;
for ( ; i < B.cols; i++ )
{
j = 0;
for ( ; j < A.rows; j++ )
{
k = 0;
for ( ; k < B.rows; k++ )
{
C.t[ i + ( C.cols * j ) ] += B.t[ i + ( B.cols * k ) ] * A.t[ k + ( A.cols * j ) ];
//k++;
}
//j++;
}
//i++;
}
return C;
}
quantum_matrix quantum_qureg2matrix( quantum_reg reg )
{
quantum_matrix m = quantum_new_matrix( 1, 1 << reg.width );
int i = 0;
for ( ; i < reg.size; i++ )
{
m.t[ (reg.node[ i ].state & 0xFFFFFFFF) ] = reg.node[ i ].amplitude;
//i++;
}
return m;
}
