/// Calculate the dot product
/// @param v :: The other vector.
double GSLVector::dot(const GSLVector &v) const {
if (size() != v.size()) {
throw std::runtime_error("Vectors have different sizes in dot product.");
}
double res = 0.0;
gsl_blas_ddot(gsl(), v.gsl(), &res);
return res;
}
/// Solve system of linear equations M*x == rhs, M is this matrix
/// This matrix is destroyed.
/// @param rhs :: The right-hand-side vector
/// @param x :: The solution vector
void GSLMatrix::solve(const GSLVector &rhs, GSLVector &x) {
if (size1() != size2()) {
throw std::runtime_error(
"System of linear equations: the matrix must be square.");
}
size_t n = size1();
if (rhs.size() != n) {
throw std::runtime_error(
"System of linear equations: right-hand side vector has wrong size.");
}
x.resize(n);
int s;
gsl_permutation *p = gsl_permutation_alloc(n);
gsl_linalg_LU_decomp(gsl(), p, &s); // matrix is modified at this moment
gsl_linalg_LU_solve(gsl(), p, rhs.gsl(), x.gsl());
gsl_permutation_free(p);
}
/// Calculate the eigensystem of a symmetric matrix
/// @param eigenValues :: Output variable that receives the eigenvalues of this
/// matrix.
/// @param eigenVectors :: Output variable that receives the eigenvectors of
/// this matrix.
void GSLMatrix::eigenSystem(GSLVector &eigenValues, GSLMatrix &eigenVectors) {
size_t n = size1();
if (n != size2()) {
throw std::runtime_error("Matrix eigenSystem: the matrix must be square.");
}
eigenValues.resize(n);
eigenVectors.resize(n, n);
auto workspace = gsl_eigen_symmv_alloc(n);
gsl_eigen_symmv(gsl(), eigenValues.gsl(), eigenVectors.gsl(), workspace);
gsl_eigen_symmv_free(workspace);
}
/// Solve system of linear equations M*x == rhs, M is this matrix
/// This matrix is destroyed.
/// @param rhs :: The right-hand-side vector
/// @param x :: The solution vector
/// @throws std::invalid_argument if the input vectors have wrong sizes.
/// @throws std::runtime_error if the GSL fails to solve the equations.
void GSLMatrix::solve(const GSLVector &rhs, GSLVector &x) {
if (size1() != size2()) {
throw std::invalid_argument(
"System of linear equations: the matrix must be square.");
}
size_t n = size1();
if (rhs.size() != n) {
throw std::invalid_argument(
"System of linear equations: right-hand side vector has wrong size.");
}
x.resize(n);
int s;
gsl_permutation *p = gsl_permutation_alloc(n);
gsl_linalg_LU_decomp(gsl(), p, &s); // matrix is modified at this moment
int res = gsl_linalg_LU_solve(gsl(), p, rhs.gsl(), x.gsl());
gsl_permutation_free(p);
if (res != GSL_SUCCESS) {
std::string message = "Failed to solve system of linear equations.\n"
"Error message returned by the GSL:\n" +
std::string(gsl_strerror(res));
throw std::runtime_error(message);
}
}
/// Matrix by vector multiplication
/// @param v :: A vector to multiply by. Must have the same size as size2().
/// @returns A vector - the result of the multiplication. Size of the returned
/// vector equals size1().
/// @throws std::invalid_argument if the input vector has a wrong size.
/// @throws std::runtime_error if the underlying GSL routine fails.
GSLVector GSLMatrix::operator*(const GSLVector &v) const {
if (v.size() != size2()) {
throw std::invalid_argument(
"Matrix by vector multiplication: wrong size of vector.");
}
GSLVector res(size1());
auto status =
gsl_blas_dgemv(CblasNoTrans, 1.0, gsl(), v.gsl(), 0.0, res.gsl());
if (status != GSL_SUCCESS) {
std::string message = "Failed to multiply matrix by a vector.\n"
"Error message returned by the GSL:\n" +
std::string(gsl_strerror(status));
throw std::runtime_error(message);
}
return res;
}
/**
* Recalculate the B-spline knots
*/
void BSpline::resetKnots()
{
bool isUniform = getAttribute("Uniform").asBool();
std::vector<double> breakPoints;
if ( isUniform )
{
// create uniform knots in the interval [StartX, EndX]
double startX = getAttribute("StartX").asDouble();
double endX = getAttribute("EndX").asDouble();
gsl_bspline_knots_uniform( startX, endX, m_bsplineWorkspace.get() );
getGSLBreakPoints( breakPoints );
storeAttributeValue( "BreakPoints", Attribute(breakPoints) );
}
else
{
// set the break points from BreakPoints vector attribute, update other attributes
breakPoints = getAttribute( "BreakPoints" ).asVector();
// check that points are in ascending order
double prev = breakPoints[0];
for(size_t i = 1; i < breakPoints.size(); ++i)
{
double next = breakPoints[i];
if ( next <= prev )
{
throw std::invalid_argument("BreakPoints must be in ascending order.");
}
prev = next;
}
int nbreaks = getAttribute( "NBreak" ).asInt();
// if number of break points change do necessary updates
if ( static_cast<size_t>(nbreaks) != breakPoints.size() )
{
storeAttributeValue("NBreak", Attribute(static_cast<int>(breakPoints.size())) );
resetGSLObjects();
resetParameters();
}
GSLVector bp = breakPoints;
gsl_bspline_knots( bp.gsl(), m_bsplineWorkspace.get() );
storeAttributeValue( "StartX", Attribute(breakPoints.front()) );
storeAttributeValue( "EndX", Attribute(breakPoints.back()) );
}
}
GSLVector::GSLVector(const GSLVector& v)
{
m_vector = gsl_vector_alloc(v.size());
gsl_vector_memcpy(m_vector, v.gsl());
}