GoldenSpiral Class Reference

Example: Golden spiral More...

Public Member Functions
	GoldenSpiral (const Options &opt)
	Actual model.
	GoldenSpiral (GoldenSpiral &p)
	Constructor for cloning p.
virtual Space *	copy (void)
	Copy during cloning.
virtual FloatVar	cost (void) const
	Cost function.
virtual void	print (std::ostream &os) const
	Print solution coordinates.
Public Member Functions inherited from Gecode::Driver::ScriptBase< Driver::ExtractStepOption< FloatMaximizeSpace > >
	ScriptBase (const Options &opt)
	Constructor.
	ScriptBase (ScriptBase &e)
	Constructor used for cloning.
virtual void	compare (const Space &home, std::ostream &os) const
	Compare with s.
Public Member Functions inherited from Gecode::Driver::ExtractStepOption< BaseSpace >
	ExtractStepOption (const Options &opt)
	Constructor that extracts the step value.
	ExtractStepOption (BaseSpace &e)
	Constructor used for cloning.

Protected Attributes
FloatVarArray	f
	The numbers.

Related Symbols
(Note that these are not member symbols.)
int	main (int argc, char *argv[])
	Main-function.

Additional Inherited Members
Static Public Member Functions inherited from Gecode::Driver::ScriptBase< Driver::ExtractStepOption< FloatMaximizeSpace > >
static std::ostream &	select_ostream (const char *sn, std::ofstream &ofs)
	Choose output stream according to sn.
static void	run (const Options &opt, Script *s=nullptr)

Detailed Description

Example: Golden spiral

The Golden Spiral is a logarithmic spiral whose growth factor is the golden ratio \(\phi=1,618\).

It is defined by the polar equation:

\[r = ae^{b\theta} \]

where

\[\operatorname{abs}(b) = \frac{\operatorname{ln}(\phi)}{\frac{\pi}{2}} \]

To get cartesian coordinates, it can be solved for \(x\) and \(y\) in terms of \(r\) and \(\theta\). By setting \(a=1\), it yields to the equation:

\[r = e^{0.30649\times\theta} \]

with

\[x=r\operatorname{cos}(\theta), \quad y=r\operatorname{sin}(\theta) \]

The tuple \((r,\theta)\) is related to the position for \(x\) and \(y\) on the curve. \(r\) and \(\theta\) are positive numbers.

To get reasonable interval starting sizes, \(x\) and \(y\) are restricted to \([-20;20]\).

Definition at line 77 of file golden-spiral.cpp.

Constructor & Destructor Documentation

GoldenSpiral() [1/2]

GoldenSpiral::GoldenSpiral ( const Options & opt )

inline

Actual model.

Definition at line 83 of file golden-spiral.cpp.

GoldenSpiral() [2/2]

GoldenSpiral::GoldenSpiral ( GoldenSpiral & p )

inline

Constructor for cloning p.

Definition at line 99 of file golden-spiral.cpp.

Member Function Documentation

copy()

virtual Space * GoldenSpiral::copy ( void )

inlinevirtual

Copy during cloning.

Definition at line 104 of file golden-spiral.cpp.

cost()

virtual FloatVar GoldenSpiral::cost ( void ) const

inlinevirtual

Cost function.

Definition at line 108 of file golden-spiral.cpp.

print()

virtual void GoldenSpiral::print ( std::ostream & os ) const

inlinevirtual

Print solution coordinates.

Reimplemented from Gecode::Driver::ScriptBase< Driver::ExtractStepOption< FloatMaximizeSpace > >.

Definition at line 112 of file golden-spiral.cpp.

Friends And Related Symbol Documentation

main()

int main ( int argc, char * argv[] )

related

Main-function.

Definition at line 122 of file golden-spiral.cpp.

Member Data Documentation

f

FloatVarArray GoldenSpiral::f

protected

The numbers.

Definition at line 80 of file golden-spiral.cpp.

---

The documentation for this class was generated from the following file:

• examples/golden-spiral.cpp