Index: trunk/MagicSoft/Mars/mtools/MFFT.cc
===================================================================
--- trunk/MagicSoft/Mars/mtools/MFFT.cc	(revision 3084)
+++ trunk/MagicSoft/Mars/mtools/MFFT.cc	(revision 3125)
@@ -700,4 +700,56 @@
 
 
+//
+// Power Spectrum Density calculation for TArrayI
+//
+TArrayF* MFFT::PowerSpectrumDensity(const TArrayI *array)
+{
+
+  fDim = array->GetSize();
+  CheckDim(fDim);
+
+  fDataF.Set(fDim);
+  //
+  // Copy the hist into an array
+  //
+  for (Int_t i=0;i<fDim;i++)
+    fDataF[i] = (Float_t)array->At(i);
+
+  RealFTF(1);
+
+  const Int_t dim2  = fDim*fDim;
+  const Int_t dim05 = fDim/2;
+  Float_t c02;
+  Float_t ck2;
+  Float_t cn2;
+  
+  TArrayF *newarray = new TArrayF(dim05);
+
+  //
+  // Fill the new histogram: 
+  //
+  // 1) P(0) = 1/(N*N) |C(0)|*|C(0)|
+  //
+  c02 = (fDataF[0]*fDataF[0]);
+  //  newarray->AddAt(c02/dim2,0);
+  //
+  // 2) P(k) = 1/(N*N) (|C(k)|*|C(k)|))
+  //
+  for (Int_t k=1;k<dim05-1;k++)
+    {
+      const Int_t k2 = k+k;
+      ck2 = (fDataF[k2]*fDataF[k2] + fDataF[k2+1]*fDataF[k2+1]);
+      newarray->AddAt(ck2/dim2,k);
+    }
+  //
+  // 3) P(N) = 1/(N*N) (|C(n/2)|*|C(n/2)|)
+  //
+  cn2 = (fDataF[1]*fDataF[1]);
+  //  newarray->AddAt(cn2,dim05-1);
+  
+  return newarray;
+}
+
+
 TArrayD* MFFT::PowerSpectrumDensity(const TArrayD *array)
 {
Index: trunk/MagicSoft/Mars/mtools/MFFT.h
===================================================================
--- trunk/MagicSoft/Mars/mtools/MFFT.h	(revision 3084)
+++ trunk/MagicSoft/Mars/mtools/MFFT.h	(revision 3125)
@@ -74,4 +74,5 @@
   TH1D* PowerSpectrumDensity(const TH1D *hist);
 
+  TArrayF* PowerSpectrumDensity(const TArrayI *array);  
   TArrayF* PowerSpectrumDensity(const TArrayF *array);
   TArrayD* PowerSpectrumDensity(const TArrayD *array);