g++ [flags ...] file ... -l /isip/tools/lib/$ISIP_BINARY/lib_algo.a

#include <Energy.h>

Energy(ALGORITHM algorithm = DEF_ALGORITHM, IMPLEMENTATION implementation = DEF_IMPLEMENTATION, float floor);
boolean eq(const Energy& arg);
boolean setAlgorithm(ALGORITHM algorithm);
boolean setFloor(float floor);

Energy egy;
VectorFloat input(L"1, 0, -1");
VectorFloat output;
egy.setAlgorithm(Energy::IDENTITY);
egy.compute(output, input);

L. Rabiner and R. Schafer, Digital Processing of Speech Signals, Prentice-Hall, Englewood Cliffs, New Jersey, USA, pp. 116, 1976.

• This example shows how to compute the energy of input vector in dB using the SUM algorithm:

  // declare an Energy object and an output vector
  //
  Energy egy;
  VectorFloat output;
  
  // set the input vector
  //
  VectorFloat input(L"0, 1, 2");
  
  // choose algorithm
  //
  enrgy.setAlgorithm(Energy::SUM);
  
  // choose implementation
  //
  egy.setImplementation(Energy::DB);
  
  // compute the energy of input data
  //
  egy.compute(output, input);

• This example shows how to compute the log power of the input vector using the FILTER algorithm:

  // declare an Energy object and an output vector
  //
  Energy egy;
  VectorFloat output;
  
  // set the input vector
  //
  
  VectorFloat input(L"0,1,2,3,4")
  
  // choose the algorithm and implementation
  //
  egy.setAlgorithm(Energy::FILTER);
  egy.setImplementation(Energy::LOG_POWER);
  
  // set up a filter
  //
  VectorFloat ma_coef(L"1,1,1");       
  VectorFloat ar_coef(L"1");
  egy.setFilter(ma_coef, ar_coef);       
  
  // compute the energy of input data
  //
  egy.compute(output, input);

• The computed energy is stored as the first element in the output vector.
  
  
• The FILTER algorithm is restricted to causal linear filters. It was implemented directly instead of using the Filter class because of some complications involving multichannel signals due to the algorithm programming interface.
  
  
• Technically, the FILTER algorithm operates in CROSS_FRAME mode, since it operates on data outside the current frame. However, the FILTER algorithm uses its own internal filter memory, and does not need to rely on the apply method's circular buffers to maintain history. Hence, only the FRAME_INTERNAL mode is allowed.
  
  
• Similarly, if the FILTER algorithm is selected, and the compute mode is used (which assumes single frame at a time processing), the programmer must manually reset the filter as desired using the init() method.