96 lines
3.2 KiB
Text
96 lines
3.2 KiB
Text
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//$$ solution.h // solve routines
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#include "boolean.h"
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#include "myexcept.h"
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#ifdef use_namespace
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namespace RBD_COMMON {
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#endif
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// Solve the equation f(x)=y for x where f is a monotone continuous
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// function of x
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// Essentially Brent s method
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// You need to derive a class from R1_R1 and override "operator()"
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// with the function you want to solve.
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// Use an object from this class in OneDimSolve
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class R1_R1
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{
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// the prototype for a Real function of a Real variable
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// you need to derive your function from this one and put in your
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// function for operator() at least. You probably also want to set up a
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// constructor to put in additional parameter values (e.g. that will not
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// vary during a solve)
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protected:
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Real x; // Current x value
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bool xSet; // true if a value assigned to x
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public:
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Real minX, maxX; // range of value x
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bool minXinf, maxXinf; // true if these are infinite
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R1_R1() : xSet(false), minXinf(true), maxXinf(true) {}
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virtual Real operator()() = 0; // function value at current x
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// set current x
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virtual void Set(Real X); // set x, check OK
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Real operator()(Real X) { Set(X); return operator()(); }
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// set x, return value
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virtual bool IsValid(Real X);
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operator Real(); // implicit conversion
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virtual ~R1_R1() {} // to keep gnu happy
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};
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class SolutionException : public BaseException
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{
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public:
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static unsigned long Select;
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SolutionException(const char* a_what = 0);
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};
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class OneDimSolve
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{
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R1_R1& function; // reference to the function
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Real accX; // accuracy in X direction
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Real accY; // accuracy in Y direction
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int lim; // maximum number of iterations
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public:
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OneDimSolve(R1_R1& f, Real AccY = 0.0001, Real AccX = 0.0)
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: function(f), accX(AccX), accY(AccY) {}
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// f is an R1_R1 function
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Real Solve(Real Y, Real X, Real Dev, int Lim=100);
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// Solve for x in Y=f(x)
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// X is the initial trial value of x
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// X+Dev is the second trial value
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// program returns a value of x such that
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// |Y-f(x)| <= accY or |f.inv(Y)-x| <= accX
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private:
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Real x[3], y[3]; // Trial values of X and Y
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int L,C,U,Last; // Locations of trial values
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int vpol, hpol; // polarities
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Real YY; // target value
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int i;
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void LookAt(int); // get new value of function
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bool Finish; // true if LookAt finds conv.
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bool Captured; // true when target surrounded
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void VFlip();
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void HFlip();
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void Flip();
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void State(int I, int J, int K);
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void Linear(int, int, int);
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void Quadratic(int, int, int);
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};
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#ifdef use_namespace
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}
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#endif
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// body file: solution.cpp
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