comparison base/Window.h @ 142:0ba66b160a02

* Add frequency plot to window shape preference -- just because...
* Fix some window shapes

     BartlettWindow,
     HammingWindow,
     HanningWindow,
     BlackmanWindow,
     GaussianWindow,
-    ParzenWindow
+    ParzenWindow,
+    NuttallWindow,
+    BlackmanHarrisWindow
 };
 
 template <typename T>
 class Window
 {

 	m_type = w.m_type;
 	m_size = w.m_size;
 	encache();
 	return *this;
     }
-    virtual ~Window() { delete m_cache; }
+    virtual ~Window() { delete[] m_cache; }
     
     void cut(T *src) const { cut(src, src); }
     void cut(T *src, T *dst) const {
 	for (size_t i = 0; i < m_size; ++i) dst[i] = src[i] * m_cache[i];
     }

     WindowType m_type;
     size_t m_size;
     T *m_cache;
     
     void encache();
+    void cosinewin(T *, T, T, T, T);
 };
 
 template <typename T>
 void Window<T>::encache()
 {

 	    mult[i + n/2] *= (1.0 - (i / T(n/2)));
 	}
 	break;
 	    
     case HammingWindow:
-	for (i = 0; i < n; ++i) {
-	    mult[i] *= (0.54 - 0.46 * cos(2 * M_PI * i / n));
-	}
+        cosinewin(mult, 0.54, 0.46, 0.0, 0.0);
 	break;
 	    
     case HanningWindow:
-	for (i = 0; i < n; ++i) {
-	    mult[i] *= (0.50 - 0.50 * cos(2 * M_PI * i / n));
-	}
+        cosinewin(mult, 0.50, 0.50, 0.0, 0.0);
 	break;
 	    
     case BlackmanWindow:
-	for (i = 0; i < n; ++i) {
-	    mult[i] *= (0.42 - 0.50 * cos(2 * M_PI * i / n)
-				 + 0.08 * cos(4 * M_PI * i / n));
-	}
+        cosinewin(mult, 0.42, 0.50, 0.08, 0.0);
 	break;
 	    
     case GaussianWindow:
 	for (i = 0; i < n; ++i) {
-            mult[i] *= exp(-(pow(i - (n-1)/2.0, 2) /
-                                      (2 * pow(0.25 * n, 2)))); // sd = 0.25
+            mult[i] *= pow(2, - pow((i - (n-1)/2.0) / ((n-1)/2.0 / 3), 2));
 	}
 	break;
 	    
     case ParzenWindow:
     {

             int wn = i - N/2;
             T m = 1.0 - 6 * pow(wn / (T(N)/2), 2) * (1.0 - abs(wn) / (T(N)/2));
             mult[i] *= m;
             mult[N-i] *= m;
         }            
-    }            
+        break;
+    }
+
+    case NuttallWindow:
+        cosinewin(mult, 0.3635819, 0.4891775, 0.1365995, 0.0106411);
 	break;
+
+    case BlackmanHarrisWindow:
+        cosinewin(mult, 0.35875, 0.48829, 0.14128, 0.01168);
+        break;
     }
 	
     m_cache = mult;
 }
 
+template <typename T>
+void Window<T>::cosinewin(T *mult, T a0, T a1, T a2, T a3)
+{
+    int n = int(m_size);
+    for (int i = 0; i < n; ++i) {
+        mult[i] *= (a0
+                    - a1 * cos(2 * M_PI * i / n)
+                    + a2 * cos(4 * M_PI * i / n)
+                    - a3 * cos(6 * M_PI * i / n));
+    }
+}
+
 #endif