Commit LivePathEffect branch to trunk!

(disabled extension/internal/bitmap/*.* in build.xml to fix compilation)

(bzr r3472)

1 files changed, 64 insertions, 0 deletions

diff --git a/src/2geom/poly-dk-solve.cpp b/src/2geom/poly-dk-solve.cpp
new file mode 100644
index 000000000..dde230dc4
--- /dev/null
+++ b/src/2geom/poly-dk-solve.cpp
@@ -0,0 +1,64 @@
+#include "poly-dk-solve.h"
+#include <iterator>
+
+/*** implementation of the Durand-Kerner method.  seems buggy*/
+
+std::complex<double> evalu(Poly const & p, std::complex<double> x) {
+    std::complex<double> result = 0;
+    std::complex<double> xx = 1;
+    
+    for(unsigned i = 0; i < p.size(); i++) {
+        result += p[i]*xx;
+        xx *= x;
+    }
+    return result;
+}
+
+std::vector<std::complex<double> > DK(Poly const & ply, const double tol) {
+    std::vector<std::complex<double> > roots;
+    const int N = ply.degree();
+    
+    std::complex<double> b(0.4, 0.9);
+    std::complex<double> p = 1;
+    for(int i = 0; i < N; i++) {
+        roots.push_back(p);
+        p *= b;
+    }
+    assert(roots.size() == ply.degree());
+    
+    double error = 0;
+    int i;
+    for( i = 0; i < 30; i++) {
+        error = 0;
+        for(int r_i = 0; r_i < N; r_i++) {
+            std::complex<double> denom = 1;
+            std::complex<double> R = roots[r_i];
+            for(int d_i = 0; d_i < N; d_i++) {
+                if(r_i != d_i)
+                    denom *= R-roots[d_i];
+            }
+            assert(norm(denom) != 0);
+	    std::complex<double> dr = evalu(ply, R)/denom;
+            error += norm(dr);
+            roots[r_i] = R - dr;
+        }
+        /*std::copy(roots.begin(), roots.end(), std::ostream_iterator<std::complex<double> >(std::cout, ",\t"));
+          std::cout << std::endl;*/
+        if(error < tol)
+            break;
+    }
+    //std::cout << error << ", " << i<< std::endl;
+    return roots;
+}
+
+
+/*
+  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 :