Struct opencv::core::ConjGradSolver

pub struct ConjGradSolver { /* private fields */ }

This class is used to perform the non-linear non-constrained minimization of a function with known gradient,

defined on an n-dimensional Euclidean space, using the Nonlinear Conjugate Gradient method. The implementation was done based on the beautifully clear explanatory article An Introduction to the Conjugate Gradient Method Without the Agonizing Pain by Jonathan Richard Shewchuk. The method can be seen as an adaptation of a standard Conjugate Gradient method (see, for example http://en.wikipedia.org/wiki/Conjugate_gradient_method) for numerically solving the systems of linear equations.

It should be noted, that this method, although deterministic, is rather a heuristic method and therefore may converge to a local minima, not necessary a global one. What is even more disastrous, most of its behaviour is ruled by gradient, therefore it essentially cannot distinguish between local minima and maxima. Therefore, if it starts sufficiently near to the local maximum, it may converge to it. Another obvious restriction is that it should be possible to compute the gradient of a function at any point, thus it is preferable to have analytic expression for gradient and computational burden should be born by the user.

The latter responsibility is accomplished via the getGradient method of a MinProblemSolver::Function interface (which represents function being optimized). This method takes point a point in n-dimensional space (first argument represents the array of coordinates of that point) and compute its gradient (it should be stored in the second argument as an array).

Note: class ConjGradSolver thus does not add any new methods to the basic MinProblemSolver interface.

Note: term criteria should meet following condition:

   termcrit.type == (TermCriteria::MAX_ITER + TermCriteria::EPS) && termcrit.epsilon > 0 && termcrit.maxCount > 0
   // or
   termcrit.type == TermCriteria::MAX_ITER) && termcrit.maxCount > 0

Implementations

impl ConjGradSolver

pub fn create( f: &Ptr<MinProblemSolver_Function>, termcrit: TermCriteria ) -> Result<Ptr<ConjGradSolver>>

This function returns the reference to the ready-to-use ConjGradSolver object.

All the parameters are optional, so this procedure can be called even without parameters at all. In this case, the default values will be used. As default value for terminal criteria are the only sensible ones, MinProblemSolver::setFunction() should be called upon the obtained object, if the function was not given to create(). Otherwise, the two ways (submit it to create() or miss it out and call the MinProblemSolver::setFunction()) are absolutely equivalent (and will drop the same errors in the same way, should invalid input be detected).

Parameters

• f: Pointer to the function that will be minimized, similarly to the one you submit via MinProblemSolver::setFunction.
• termcrit: Terminal criteria to the algorithm, similarly to the one you submit via MinProblemSolver::setTermCriteria.

C++ default parameters

• f: PtrConjGradSolver::Function()
• termcrit: TermCriteria(TermCriteria::MAX_ITER+TermCriteria::EPS,5000,0.000001)

pub fn create_def() -> Result<Ptr<ConjGradSolver>>

This function returns the reference to the ready-to-use ConjGradSolver object.

All the parameters are optional, so this procedure can be called even without parameters at all. In this case, the default values will be used. As default value for terminal criteria are the only sensible ones, MinProblemSolver::setFunction() should be called upon the obtained object, if the function was not given to create(). Otherwise, the two ways (submit it to create() or miss it out and call the MinProblemSolver::setFunction()) are absolutely equivalent (and will drop the same errors in the same way, should invalid input be detected).

Parameters

• f: Pointer to the function that will be minimized, similarly to the one you submit via MinProblemSolver::setFunction.
• termcrit: Terminal criteria to the algorithm, similarly to the one you submit via MinProblemSolver::setTermCriteria.

Note

This alternative version of ConjGradSolver::create function uses the following default values for its arguments:

• f: PtrConjGradSolver::Function()
• termcrit: TermCriteria(TermCriteria::MAX_ITER+TermCriteria::EPS,5000,0.000001)

Trait Implementations

impl AlgorithmTrait for ConjGradSolver

fn as_raw_mut_Algorithm(&mut self) -> *mut c_void

fn clear(&mut self) -> Result<()>

Clears the algorithm state

fn read(&mut self, fn_: &impl FileNodeTraitConst) -> Result<()>

Reads algorithm parameters from a file storage

impl AlgorithmTraitConst for ConjGradSolver

fn as_raw_Algorithm(&self) -> *const c_void

fn write(&self, fs: &mut impl FileStorageTrait) -> Result<()>

Stores algorithm parameters in a file storage

fn write_1(&self, fs: &mut impl FileStorageTrait, name: &str) -> Result<()>

Stores algorithm parameters in a file storage

fn write_with_name(&self, fs: &Ptr<FileStorage>, name: &str) -> Result<()>

@deprecated

fn write_with_name_def(&self, fs: &Ptr<FileStorage>) -> Result<()>

👎Deprecated:

Note

Deprecated: ## Note This alternative version of AlgorithmTraitConst::write_with_name function uses the following default values for its arguments:

fn empty(&self) -> Result<bool>

Returns true if the Algorithm is empty (e.g. in the very beginning or after unsuccessful read

fn save(&self, filename: &str) -> Result<()>

Saves the algorithm to a file. In order to make this method work, the derived class must implement Algorithm::write(FileStorage& fs).

fn get_default_name(&self) -> Result<String>

Returns the algorithm string identifier. This string is used as top level xml/yml node tag when the object is saved to a file or string.

impl Boxed for ConjGradSolver

unsafe fn from_raw( ptr: <ConjGradSolver as OpenCVFromExtern>::ExternReceive ) -> Self

Wrap the specified raw pointer

fn into_raw( self ) -> <ConjGradSolver as OpenCVTypeExternContainer>::ExternSendMut

Return the underlying raw pointer while consuming this wrapper.

fn as_raw(&self) -> <ConjGradSolver as OpenCVTypeExternContainer>::ExternSend

Return the underlying raw pointer.

fn as_raw_mut( &mut self ) -> <ConjGradSolver as OpenCVTypeExternContainer>::ExternSendMut

Return the underlying mutable raw pointer

impl ConjGradSolverTrait for ConjGradSolver

fn as_raw_mut_ConjGradSolver(&mut self) -> *mut c_void

impl ConjGradSolverTraitConst for ConjGradSolver

fn as_raw_ConjGradSolver(&self) -> *const c_void

impl Debug for ConjGradSolver

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for ConjGradSolver

fn drop(&mut self)

Executes the destructor for this type.

impl From<ConjGradSolver> for Algorithm

fn from(s: ConjGradSolver) -> Self

Converts to this type from the input type.

impl From<ConjGradSolver> for MinProblemSolver

fn from(s: ConjGradSolver) -> Self

Converts to this type from the input type.

impl MinProblemSolverTrait for ConjGradSolver

fn as_raw_mut_MinProblemSolver(&mut self) -> *mut c_void

fn set_function(&mut self, f: &Ptr<MinProblemSolver_Function>) -> Result<()>

Setter for the optimized function.

fn set_term_criteria(&mut self, termcrit: TermCriteria) -> Result<()>

Set terminal criteria for solver.

fn minimize(&mut self, x: &mut impl ToInputOutputArray) -> Result<f64>

actually runs the algorithm and performs the minimization.

impl MinProblemSolverTraitConst for ConjGradSolver

fn as_raw_MinProblemSolver(&self) -> *const c_void

fn get_function(&self) -> Result<Ptr<MinProblemSolver_Function>>

Getter for the optimized function.

fn get_term_criteria(&self) -> Result<TermCriteria>

Getter for the previously set terminal criteria for this algorithm.

impl TryFrom<Algorithm> for ConjGradSolver

type Error = Error

The type returned in the event of a conversion error.

fn try_from(s: Algorithm) -> Result<Self>

Performs the conversion.

impl TryFrom<MinProblemSolver> for ConjGradSolver

type Error = Error

The type returned in the event of a conversion error.

fn try_from(s: MinProblemSolver) -> Result<Self>

Performs the conversion.

impl Send for ConjGradSolver