diff --git a/presentation/presentation.tex b/presentation/presentation.tex
new file mode 100644
index 0000000..e69de29
diff --git a/rapport/rapport.tex b/rapport/rapport.tex
new file mode 100644
index 0000000..e69de29
diff --git a/tests/src/math.hpp b/tests/src/math.hpp
index fbfaf00..46bcb99 100644
--- a/tests/src/math.hpp
+++ b/tests/src/math.hpp
@@ -33,11 +33,17 @@ namespace math {
     return complex(res.real()/sig.size(), res.imag()/sig.size());
   };
 
+  //TODO: implémenter la fonction
+  csignal diff(const csignal& input, complex mean) {
+    return csignal();
+  }
+
   //TODO implémenter la fft
   csignal fft_rec(const csignal& input) {
     int size = input.size();
 
     if (size == 1) {
+      //TODO: que faire dans ce cas ?
       return csignal();
     } else {
       csignal odd;
@@ -79,10 +85,18 @@ namespace math {
     contour cont;
     auto tf_it = tfd.begin();
     auto cont_it = cont.begin();
+    //TODO: trouver les bonnes valeurs
+    int kmin = 0;
+    int kmax = 2*cmax;
 
-    for (auto tf_it = tfd.begin(); tf_it != tfd.end(); ++tf_it) {
-      //TODO retrouver la formule
-      //*cont_it = mean + ...; 
+    for (int m=0; m<tfd.size(); ++m) {
+      //TODO: retrouver la formule
+      complex sum;
+      for (int k=kmin; k<kmax; ++k) {
+        sum += tfd[k]*std::exp(complex(0, 2*pi()*k*m/tfd.size()));
+      }
+      complex zm = mean + sum;
+      *(cont_it++) = cv::Point(zm.real(), zm.imag());
     }
     return cont;
   };
@@ -91,6 +105,7 @@ namespace math {
     contour res;
     csignal z = cont2sig(cont);
     complex zm = mean(z);
+    //TODO: fft(diff(z, zm));
     csignal tfd = fft(z);
     return coef2cont(tfd, zm, 0, cmax);
   };