1 files changed, 59 insertions, 0 deletions
diff --git a/src/2geom/sbasis-poly.cpp b/src/2geom/sbasis-poly.cpp
new file mode 100644
index 0000000..ffee43f
--- /dev/null
+++ b/src/2geom/sbasis-poly.cpp
@@ -0,0 +1,59 @@
+#include <2geom/sbasis-poly.h>
+
+namespace Geom{
+
+/** Changes the basis of p to be sbasis.
+ \param p the Monomial basis polynomial
+ \returns the Symmetric basis polynomial
+
+This algorithm is horribly slow and numerically terrible.  Only for testing.
+*/
+SBasis poly_to_sbasis(Poly const & p) {
+    SBasis x = Linear(0, 1);
+    SBasis r;
+    
+    for(int i = p.size()-1; i >= 0; i--) {
+        r = SBasis(Linear(p[i], p[i])) + multiply(x, r);
+    }
+    r.normalize();
+    return r;
+	
+}
+
+/** Changes the basis of p to be monomial.
+ \param p the Symmetric basis polynomial
+ \returns the Monomial basis polynomial
+
+This algorithm is horribly slow and numerically terrible.  Only for testing.
+*/
+Poly sbasis_to_poly(SBasis const & sb) {
+    if(sb.isZero())
+        return Poly();
+    Poly S; // (1-x)x = -1*x^2 + 1*x + 0
+    Poly A, B;
+    B.push_back(0);
+    B.push_back(1);
+    A.push_back(1);
+    A.push_back(-1);
+    S = A*B;
+    Poly r;
+    
+    for(int i = sb.size()-1; i >= 0; i--) {
+        r = S*r + sb[i][0]*A + sb[i][1]*B;
+    }
+    r.normalize();
+    return r;
+}
+
+};
+
+/*
+  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:fileencoding=utf-8:textwidth=99 :