bool isDIRKButcherTableau( const RKButcherTableauBase<Scalar>& rkbt )
{
if (isEmptyRKButcherTableau(rkbt)) {
return false;
}
typedef ScalarTraits<Scalar> ST;
int numStages_local = rkbt.numStages();
const Teuchos::SerialDenseMatrix<int,Scalar> A_local = rkbt.A();
for (int i=0 ; i<numStages_local ; ++i) {
for (int j=0 ; j<numStages_local ; ++j) {
if ((j>i) && (A_local(i,j) != ST::zero())) {
return false;
}
}
}
return true;
}
bool isSDIRKButcherTableau( const RKButcherTableauBase<Scalar>& rkbt )
{
if (isEmptyRKButcherTableau(rkbt)) {
return false;
}
if (!isDIRKButcherTableau(rkbt)) {
return false;
}
// Verify the diagonal entries are all equal.
typedef ScalarTraits<Scalar> ST;
int numStages_local = rkbt.numStages();
const Teuchos::SerialDenseMatrix<int,Scalar> A_local = rkbt.A();
Scalar val = A_local(0,0);
for (int i=0 ; i<numStages_local ; ++i) {
if (A_local(i,i) != val) {
return false;
}
}
return true;
}
bool RKButcherTableauBase<Scalar>::operator== (const RKButcherTableauBase<Scalar>& rkbt) const
{
if (this->numStages() != rkbt.numStages()) {
return false;
}
if (this->order() != rkbt.order()) {
return false;
}
int N = rkbt.numStages();
// Check b and c first:
const Teuchos::SerialDenseVector<int,Scalar> b_ = this->b();
const Teuchos::SerialDenseVector<int,Scalar> c_ = this->c();
const Teuchos::SerialDenseVector<int,Scalar> other_b = rkbt.b();
const Teuchos::SerialDenseVector<int,Scalar> other_c = rkbt.c();
for (int i=0 ; i<N ; ++i) {
if (b_(i) != other_b(i)) {
return false;
}
if (c_(i) != other_c(i)) {
return false;
}
}
// Then check A:
const Teuchos::SerialDenseMatrix<int,Scalar>& A_ = this->A();
const Teuchos::SerialDenseMatrix<int,Scalar>& other_A = rkbt.A();
for (int i=0 ; i<N ; ++i) {
for (int j=0 ; j<N ; ++j) {
if (A_(i,j) != other_A(i,j)) {
return false;
}
}
}
return true;
}
bool isERKButcherTableau( const RKButcherTableauBase<Scalar>& rkbt)
{
if (isEmptyRKButcherTableau(rkbt)) {
return false;
}
// Verify the diagonal is zero and the upper triangular part is zero
typedef ScalarTraits<Scalar> ST;
int numStages_local = rkbt.numStages();
const Teuchos::SerialDenseMatrix<int,Scalar> A_local = rkbt.A();
for (int i=0 ; i<numStages_local ; ++i) {
for (int j=0 ; j<numStages_local ; ++j) {
if ((j>=i) && ((A_local(i,j) != ST::zero()))) {
return false;
}
}
}
const Teuchos::SerialDenseVector<int,Scalar> c_local = rkbt.c();
if( c_local(0) != ST::zero() ) {
return false;
}
// 08/13/08 tscoffe: I'm not sure what else I can check for b & c...
return true;
}
bool isEmptyRKButcherTableau( const RKButcherTableauBase<Scalar>& rkbt ) {
typedef ScalarTraits<Scalar> ST;
// Check that numStages > 0
if (rkbt.numStages() == 0) {
return true;
}
// Check that the b vector has _some_ non-zero entry
int numNonZero = 0;
int numStages_local = rkbt.numStages();
const Teuchos::SerialDenseVector<int,Scalar> b_local = rkbt.b();
for (int i=0 ; i<numStages_local ; ++i) {
if (b_local(i) != ST::zero()) {
numNonZero++;
}
}
if (numNonZero == 0) {
return true;
}
// There is no reason to check A and c because they can be zero and you're
// producing an explicit method as long as b has something in it.
return false;
}
E_RKButcherTableauTypes determineRKBTType(const RKButcherTableauBase<Scalar>& rkbt) {
if (isEmptyRKButcherTableau(rkbt)) {
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_INVALID;
}
if (isERKButcherTableau(rkbt)) {
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_ERK;
}
if (rkbt.numStages() == 1) {
// In this case, its just an IRK method.
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_IRK;
}
if (isSDIRKButcherTableau(rkbt)) {
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_SDIRK;
}
if (isDIRKButcherTableau(rkbt)) {
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_DIRK;
}
if (isIRKButcherTableau(rkbt)) {
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_IRK;
}
return RYTHMOS_RK_BUTCHER_TABLEAU_TYPE_INVALID;
}