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| author | JF Barraud <jf.barraud@gmail.com> | 2009-03-09 01:47:39 +0000 |
|---|---|---|
| committer | jfbarraud <jfbarraud@users.sourceforge.net> | 2009-03-09 01:47:39 +0000 |
| commit | fffb14c92df4ff0efb9271708984c75ca12b30d6 (patch) | |
| tree | 04a75637990939efdd4da28826357ff214bafc22 /src/2geom/poly-laguerre-solve.cpp | |
| parent | part of bug #339660; can not use Add/Rename dialog to create layer with no pr... (diff) | |
| download | inkscape-fffb14c92df4ff0efb9271708984c75ca12b30d6.tar.gz inkscape-fffb14c92df4ff0efb9271708984c75ca12b30d6.zip | |
2geom update
(bzr r7453)
Diffstat (limited to 'src/2geom/poly-laguerre-solve.cpp')
| -rw-r--r-- | src/2geom/poly-laguerre-solve.cpp | 157 |
1 files changed, 0 insertions, 157 deletions
diff --git a/src/2geom/poly-laguerre-solve.cpp b/src/2geom/poly-laguerre-solve.cpp deleted file mode 100644 index 5b59690b7..000000000 --- a/src/2geom/poly-laguerre-solve.cpp +++ /dev/null @@ -1,157 +0,0 @@ -#include <2geom/poly-laguerre-solve.h> -#include <iterator> - - -namespace Geom { - -typedef std::complex<double> cdouble; - -cdouble laguerre_internal_complex(Poly const & p, - double x0, - double tol, - bool & quad_root) { - cdouble a = 2*tol; - cdouble xk = x0; - double n = p.degree(); - quad_root = false; - const unsigned shuffle_rate = 10; - //static double shuffle[] = {0, 0.5, 0.25, 0.75, 0.125, 0.375, 0.625, 0.875, 1.0}; - unsigned shuffle_counter = 0; - while(std::norm(a) > (tol*tol)) { - //std::cout << "xk = " << xk << std::endl; - cdouble b = p.back(); - cdouble d = 0, f = 0; - double err = abs(b); - double abx = abs(xk); - for(int j = p.size()-2; j >= 0; j--) { - f = xk*f + d; - d = xk*d + b; - b = xk*b + p[j]; - err = abs(b) + abx*err; - } - - err *= 1e-7; // magic epsilon for convergence, should be computed from tol - - cdouble px = b; - if(abs(b) < err) - return xk; - //if(std::norm(px) < tol*tol) - // return xk; - cdouble G = d / px; - cdouble H = G*G - f / px; - - //std::cout << "G = " << G << "H = " << H; - cdouble radicand = (n - 1)*(n*H-G*G); - //assert(radicand.real() > 0); - if(radicand.real() < 0) - quad_root = true; - //std::cout << "radicand = " << radicand << std::endl; - if(G.real() < 0) // here we try to maximise the denominator avoiding cancellation - a = - sqrt(radicand); - else - a = sqrt(radicand); - //std::cout << "a = " << a << std::endl; - a = n / (a + G); - //std::cout << "a = " << a << std::endl; - //if(shuffle_counter % shuffle_rate == 0) - //a *= shuffle[shuffle_counter / shuffle_rate]; - xk -= a; - shuffle_counter++; - if(shuffle_counter >= 90) - break; - } - //std::cout << "xk = " << xk << std::endl; - return xk; -} - -double laguerre_internal(Poly const & p, - Poly const & pp, - Poly const & ppp, - double x0, - double tol, - bool & quad_root) { - double a = 2*tol; - double xk = x0; - double n = p.degree(); - quad_root = false; - while(a*a > (tol*tol)) { - //std::cout << "xk = " << xk << std::endl; - double px = p(xk); - if(px*px < tol*tol) - return xk; - double G = pp(xk) / px; - double H = G*G - ppp(xk) / px; - - //std::cout << "G = " << G << "H = " << H; - double radicand = (n - 1)*(n*H-G*G); - assert(radicand > 0); - //std::cout << "radicand = " << radicand << std::endl; - if(G < 0) // here we try to maximise the denominator avoiding cancellation - a = - sqrt(radicand); - else - a = sqrt(radicand); - //std::cout << "a = " << a << std::endl; - a = n / (a + G); - //std::cout << "a = " << a << std::endl; - xk -= a; - } - //std::cout << "xk = " << xk << std::endl; - return xk; -} - - -std::vector<cdouble > -laguerre(Poly p, const double tol) { - std::vector<cdouble > solutions; - //std::cout << "p = " << p << " = "; - while(p.size() > 1) - { - double x0 = 0; - bool quad_root = false; - cdouble sol = laguerre_internal_complex(p, x0, tol, quad_root); - //if(abs(sol) > 1) break; - Poly dvs; - if(quad_root) { - dvs.push_back((sol*conj(sol)).real()); - dvs.push_back(-(sol + conj(sol)).real()); - dvs.push_back(1.0); - //std::cout << "(" << dvs << ")"; - //solutions.push_back(sol); - //solutions.push_back(conj(sol)); - } else { - //std::cout << sol << std::endl; - dvs.push_back(-sol.real()); - dvs.push_back(1.0); - solutions.push_back(sol); - //std::cout << "(" << dvs << ")"; - } - Poly r; - p = divide(p, dvs, r); - //std::cout << r << std::endl; - } - return solutions; -} - -std::vector<double> -laguerre_real_interval(Poly const & /*ply*/, - const double /*lo*/, const double /*hi*/, - const double /*tol*/) -{ - /* not implemented*/ - assert(false); - std::vector<double> result; - return result; -} - -} // namespace Geom - -/* - Local Variables: - mode:c++ - c-file-style:"stroustrup" - c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) - indent-tabs-mode:nil - fill-column:99 - End: -*/ -// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 : |
