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| author | Jon A. Cruz <jon@joncruz.org> | 2008-02-25 05:29:06 +0000 |
|---|---|---|
| committer | joncruz <joncruz@users.sourceforge.net> | 2008-02-25 05:29:06 +0000 |
| commit | 65643d58d14380cbbbd24b5a0fec93a991f1bb92 (patch) | |
| tree | d2f92224223e77940da2ce0603c3c021eeef47e0 /src/2geom/poly-laguerre-solve.cpp | |
| parent | svg element referenced by id part of feImage filter rendering. (diff) | |
| download | inkscape-65643d58d14380cbbbd24b5a0fec93a991f1bb92.tar.gz inkscape-65643d58d14380cbbbd24b5a0fec93a991f1bb92.zip | |
Line-end fix
(bzr r4845)
Diffstat (limited to 'src/2geom/poly-laguerre-solve.cpp')
| -rw-r--r-- | src/2geom/poly-laguerre-solve.cpp | 294 |
1 files changed, 147 insertions, 147 deletions
diff --git a/src/2geom/poly-laguerre-solve.cpp b/src/2geom/poly-laguerre-solve.cpp index 921ec3e3b..766f16eda 100644 --- a/src/2geom/poly-laguerre-solve.cpp +++ b/src/2geom/poly-laguerre-solve.cpp @@ -1,147 +1,147 @@ -#include "poly-laguerre-solve.h"
-#include <iterator>
-
-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) {
-}
-
-/*
- 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 :
+#include "poly-laguerre-solve.h" +#include <iterator> + +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) { +} + +/* + 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 : |
