bool link_sparse_hessian(
size_t size ,
size_t repeat ,
CppAD::vector<double>& x ,
const CppAD::vector<size_t>& row ,
const CppAD::vector<size_t>& col ,
CppAD::vector<double>& hessian )
{
// -----------------------------------------------------
// setup
typedef vector<double> DblVector;
typedef vector< std::set<size_t> > SetVector;
typedef CppAD::AD<double> ADScalar;
typedef vector<ADScalar> ADVector;
size_t i, j, k;
size_t order = 0; // derivative order corresponding to function
size_t m = 1; // number of dependent variables
size_t n = size; // number of independent variables
size_t K = row.size(); // number of non-zeros in lower triangle
ADVector a_x(n); // AD domain space vector
ADVector a_y(m); // AD range space vector
DblVector w(m); // double range space vector
DblVector hes(K); // non-zeros in lower triangle
CppAD::ADFun<double> f; // AD function object
// weights for hessian calculation (only one component of f)
w[0] = 1.;
// use the unspecified fact that size is non-decreasing between calls
static size_t previous_size = 0;
bool print = (repeat > 1) & (previous_size != size);
previous_size = size;
// declare sparsity pattern
# if USE_SET_SPARSITY
SetVector sparsity(n);
# else
typedef vector<bool> BoolVector;
BoolVector sparsity(n * n);
# endif
// initialize all entries as zero
for(i = 0; i < n; i++)
{ for(j = 0; j < n; j++)
hessian[ i * n + j] = 0.;
}
// ------------------------------------------------------
extern bool global_retape;
if( global_retape) while(repeat--)
{ // choose a value for x
CppAD::uniform_01(n, x);
for(j = 0; j < n; j++)
a_x[j] = x[j];
// declare independent variables
Independent(a_x);
// AD computation of f(x)
CppAD::sparse_hes_fun<ADScalar>(n, a_x, row, col, order, a_y);
// create function object f : X -> Y
f.Dependent(a_x, a_y);
extern bool global_optimize;
if( global_optimize )
{ print_optimize(f, print, "cppad_sparse_hessian_optimize", size);
print = false;
}
// calculate the Hessian sparsity pattern for this function
calc_sparsity(sparsity, f);
// structure that holds some of work done by SparseHessian
CppAD::sparse_hessian_work work;
// calculate this Hessian at this x
f.SparseHessian(x, w, sparsity, row, col, hes, work);
for(k = 0; k < K; k++)
{ hessian[ row[k] * n + col[k] ] = hes[k];
hessian[ col[k] * n + row[k] ] = hes[k];
}
}
else
{ // choose a value for x
CppAD::uniform_01(n, x);
for(j = 0; j < n; j++)
a_x[j] = x[j];
// declare independent variables
Independent(a_x);
// AD computation of f(x)
CppAD::sparse_hes_fun<ADScalar>(n, a_x, row, col, order, a_y);
// create function object f : X -> Y
f.Dependent(a_x, a_y);
extern bool global_optimize;
if( global_optimize )
{ print_optimize(f, print, "cppad_sparse_hessian_optimize", size);
print = false;
}
// calculate the Hessian sparsity pattern for this function
calc_sparsity(sparsity, f);
// declare structure that holds some of work done by SparseHessian
CppAD::sparse_hessian_work work;
while(repeat--)
{ // choose a value for x
CppAD::uniform_01(n, x);
// calculate sparsity at this x
f.SparseHessian(x, w, sparsity, row, col, hes, work);
for(k = 0; k < K; k++)
{ hessian[ row[k] * n + col[k] ] = hes[k];
hessian[ col[k] * n + row[k] ] = hes[k];
}
}
}
return true;
}
int
mat_rank(int dim, double **mat)
{
int i, j;
int count = 0;
double *dr = NULL, *di = NULL;
double **tmp;
dr = new_double_vector(dim);
di = new_double_vector(dim);
tmp = new_double_matrix(dim, dim);
/* 計算途中で値が上書きされるから元の行列のコピーを使う */
for(i = 0; i < dim; i++)
for(j = 0; j < dim; j++)
tmp[i][j] = mat[i][j];
/* 固有値の計算 */
hes(tmp, dim);
hqr(tmp, dr, di, dim);
/* 固有値を調べる */
/* drが実数成分、diが虚数成分 */
for(i = 0; i < dim; i++)
if(dr[i] > 0.0 && (!(di[i] > 0.0 || di[i] < 0.0)))
count++;
/* 配列を解放 */
free_double_vector(dr);
free_double_vector(di);
free_double_matrix(tmp);
return count;
}
Vector ADFun<Base>::Hessian(const Vector &x, size_t i)
{ size_t j;
size_t k;
size_t l;
size_t n = Domain();
size_t m = Range();
// check Vector is Simple Vector class with Base type elements
CheckSimpleVector<Base, Vector>();
CppADUsageError(
x.size() == n,
"Hessian: length of x not equal domain dimension for f"
);
CppADUsageError(
i < m,
"Hessian: index i is not less than range dimension for f"
);
// point at which we are evaluating the Hessian
Forward(0, x);
// define the return value
Vector hes(n * n);
// direction vector for calls to forward
Vector u(n);
for(j = 0; j < n; j++)
u[j] = Base(0);
// direction vector for calls to reverse
Vector w(m);
for(l = 0; l < m; l++)
w[l] = Base(0);
w[i] = Base(1);
// location for return values from Reverse
Vector ddw(n * 2);
// loop over forward direstions
for(j = 0; j < n; j++)
{ // evaluate partials of entire function w.r.t. j-th coordinate
u[j] = Base(1);
Forward(1, u);
u[j] = Base(0);
// evaluate derivative of partial corresponding to F_i
ddw = Reverse(2, w);
// return desired components
for(k = 0; k < n; k++)
hes[k * n + j] = ddw[k * 2 + 1];
}
return hes;
}
Vector ADFun<Base>::Hessian(const Vector &x, const Vector &w)
{ size_t j;
size_t k;
size_t n = Domain();
// check Vector is Simple Vector class with Base type elements
CheckSimpleVector<Base, Vector>();
CPPAD_ASSERT_KNOWN(
size_t(x.size()) == n,
"Hessian: length of x not equal domain dimension for f"
);
CPPAD_ASSERT_KNOWN(
size_t(w.size()) == Range(),
"Hessian: length of w not equal range dimension for f"
);
// point at which we are evaluating the Hessian
Forward(0, x);
// define the return value
Vector hes(n * n);
// direction vector for calls to forward
Vector u(n);
for(j = 0; j < n; j++)
u[j] = Base(0);
// location for return values from Reverse
Vector ddw(n * 2);
// loop over forward directions
for(j = 0; j < n; j++)
{ // evaluate partials of entire function w.r.t. j-th coordinate
u[j] = Base(1);
Forward(1, u);
u[j] = Base(0);
// evaluate derivative of partial corresponding to F_i
ddw = Reverse(2, w);
// return desired components
for(k = 0; k < n; k++)
hes[k * n + j] = ddw[k * 2 + 1];
}
return hes;
}
