Add hps functions #3

src/voyx/etc/Convert.HPS.h

@@ -0,0 +1,54 @@
+#pragma once
+
+#include <voyx/Header.h>
+
+// http://musicweb.ucsd.edu/~trsmyth/analysis/Harmonic_Product_Spectrum.html
+
+namespace $$
+{
+  template<typename T>
+  std::vector<T> hpsmul(const std::vector<T>& vector, const size_t depth, const T empty = 0)
+  {
+    std::vector<T> product(vector.begin(), vector.end());
+
+    for (size_t step = 2; step < depth + 2; ++step)
+    {
+      std::vector<T> harmonic(vector.size(), empty);
+
+      for (size_t i = 0, j = 0; i < vector.size(); i += step, j += 1)
+      {
+        harmonic[j] = vector[i];
+      }
+
+      for (size_t i = 0; i < vector.size(); ++i)
+      {
+        product[i] /* multiply */ *= harmonic[i];
+      }
+    }
+
+    return product;
+  }
+
+  template<typename T>
+  std::vector<T> hpsadd(const std::vector<T>& vector, const size_t depth, const T empty = -120)
+  {
+    std::vector<T> product(vector.begin(), vector.end());
+
+    for (size_t step = 2; step < depth + 2; ++step)
+    {
+      std::vector<T> harmonic(vector.size(), empty);
+
+      for (size_t i = 0, j = 0; i < vector.size(); i += step, j += 1)
+      {
+        harmonic[j] = vector[i];
+      }
+
+      for (size_t i = 0; i < vector.size(); ++i)
+      {
+        product[i] /* add */ += harmonic[i];
+      }
+    }
+
+    return product;
+  }
+}

src/voyx/etc/Convert.h

@@ -10,6 +10,7 @@
 #include <voyx/etc/Convert.DFT.h>
 #include <voyx/etc/Convert.FFT.h>
 #include <voyx/etc/Convert.MIDI.h>
+#include <voyx/etc/Convert.HPS.h>
 
 #include <voyx/etc/Convert.String.h>
 #include <voyx/etc/Convert.Type.h>