slev_08.cc

这是一个从音频信号里提取特征参量的程序

// file: $isip/class/search/SearchLevel/slev_08.cc
// version: $Id: slev_08.cc,v 1.12 2003/01/22 23:18:28 huang Exp $
//

// isip include files
//
#include "SearchLevel.h"

// method: loadNSymbolModel
//
// arguments:
//  Sof& sof: (input) sof file object
//  long tag: (input) sof object instance tag
//
// return: a boolean value indicating status
//
// this method reads context mapping information from an Sof file
//
boolean SearchLevel::loadNSymbolModel(Sof& sof_a, long tag_a) {

  // if no tag is specified, the tag should be this level number
  //
  if (tag_a == DEF_TAG) {
    tag_a = (long)level_index_d;
  }

  // make sure the symbol table has been loaded
  //
  long num_symbols = symbol_table_d.length();  
  if (num_symbols < 1) {
    return Error::handle(name(), L"loadContextMapping", Error::ARG, __FILE__, __LINE__);
  }

  // setup the symbol table
  //
  Vector<String> symbol_table(num_symbols);
  for (long i=0; i < num_symbols; i++) {
    symbol_table(i).assign(symbol_table_d(i));
  }

  // set the language model order
  //
  nsymbol_model_d.setOrder(nsymbol_order_d);
  
  // load the nsymbol model
  //  
  if (!nsymbol_model_d.load(sof_a, tag_a, symbol_table)) {
    return Error::handle(name(), L"loadNSymbolModel", Error::ARG, __FILE__, __LINE__);
  }
  
  // exit gracefully
  //
  return true;
}

// method: storeContextMapping
//
// arguments:
//  Sof& sof: (input) sof file object
//  long tag: (input) sof object instance tag
//
// return: a boolean value indicating status
//
// this method reads context mapping information from an Sof file
//
boolean SearchLevel::storeContextMapping(Sof& sof_a, long tag_a) {

  // if no tag is specified, the tag should be this level number
  //
  if (tag_a == DEF_TAG) {
    tag_a = (long)level_index_d;
  }
  
  // write the context map at this level
  //
  context_map_d.write(sof_a, tag_a, PARAM_CONTEXT_MAPPING);
  
  // gracefully exit
  //
  return true;  
}

// method: loadContextMapping
//
// arguments:
//  Sof& sof: (input) sof file object
//  long tag: (input) sof object instance tag
//
// return: a boolean value indicating status
//
// this method reads context mapping information from an Sof file
//
boolean SearchLevel::loadContextMapping(Sof& sof_a, long tag_a) {

  // if no tag is specified, the tag should be this level number
  //
  if (tag_a == DEF_TAG) {
    tag_a = (long)level_index_d;
  }

  // make sure the symbol table has been loaded
  //
  long num_symbols = symbol_table_d.length();  
  if (num_symbols < 1) {
    return Error::handle(name(), L"loadContextMapping", Error::ARG, __FILE__, __LINE__);
  }
  
  // read the context map at this level
  //
  context_map_d.read(sof_a, tag_a, PARAM_CONTEXT_MAPPING);

  // when there is a context mapping table at this level
  //
  if (context_map_d.length() > 0) {
  
    // add start and terminal search symbol to the symbol table
    //
    symbol_table_d.concat(SearchSymbol::NO_LEFT_CONTEXT);
    symbol_table_d.concat(SearchSymbol::NO_RIGHT_CONTEXT);
    
    // set up start and terminal search node for each subgraph
    //
    for (long i = 0; i < sub_graphs_d.length(); i++) {
      
      // start vertex
      //
      SearchNode* snode_p = new SearchNode();
      snode_p->setSearchLevel(this);
      snode_p->setSymbol(SearchSymbol::NO_LEFT_CONTEXT);
      sub_graphs_d(i).getStart()->setItem(snode_p);
      
      // terminal vertex
      //
      snode_p = new SearchNode();
      snode_p->setSearchLevel(this);
      snode_p->setSymbol(SearchSymbol::NO_RIGHT_CONTEXT);
      sub_graphs_d(i).getTerm()->setItem(snode_p);
    }
    
    // insert all context pairs into the context mapping hash table
    //
    long total_context_length = left_context_d + right_context_d + 1;

    // check the context length
    //
    if ( context_map_d.length() > 0 ){
      if (context_map_d(0).getContext().length() != total_context_length) {
	total_context_length = context_map_d(0).getContext().length();
	String msg(L"Warning: left_context_d + right_context_d + 1 != total context length\n check the setting for right/left context length and the length of context mapping");
	Console::put(msg);
	context_map_d(0).getContext().debug(L"a invalid context");
      }
    }
    
    Context context(total_context_length);
    
    // loop over all context pairs
    //
    for (long i = 0; i < context_map_d.length(); i++) {
      
      // loop over the symbols in the context
      //
      for (long j = 0; j < total_context_length; j++) {
	
	SearchSymbol ss(context_map_d(i).getContext()(j));
	long symbol_id = getSymbolIndex(ss);
	
	// check whether the symbol is valid
	//
	if (symbol_id == -1) {
	  ss.debug(L"symbol");
	  return Error::handle(name(), L"loadContextMapping", Error::ARG, __FILE__, __LINE__);
	}
	else {
	  context.assignAndAdvance(symbol_id);
	}
      }
      
      // insert a context specification into the hash table
      //
      Ulong index = context_map_d(i).getContextIndex();

      // check if the context is already in the table
      //
      Ulong* existing_index = context_hash_d.get(context);

      // if this context is not in the table yet, insert it
      //
      if (existing_index == NULL) {
	context_hash_d.insert(context, &index);
      }
      
      // if the context is already in the table, then check whether
      // the index of the model is the same as the one from table
      //
      else {

	// if indices are different, explain conflict and return error
	//
	if (!existing_index->eq(index)) {
	  context.debug(L"Context:");
	  String out;
	  out.concat(L" is already in context mapping table with the index: ");
	  out.concat(*existing_index);
	  out.concat(L"\n while new index is: ");
	  out.concat(index);
	  Console::put(out);
	  return Error::handle(name(), L"loadContextMapping", Error::ARG,
			       __FILE__, __LINE__);
	}
	
	// otherwise indices are not conflicting, just print a warning
	//
	else {
	  context.debug(L"Warning: This context is already in the table:");
	}
      }
    }
    
    // output the debugging information
    //
    if (debug_level_d >= Integral::ALL) {     
      context_hash_d.debug(L"context hash table:");
    }
  }
  
  // when there is NO context mapping table at this level
  //
  else {
    
    // symbols will be mapped to the model with the same index at lower level
    //
    Context dummy(1);
    
    for (Ulong i = 0; i < (ulong)num_symbols; i++) {
      dummy.assignAndAdvance(i);
      context_hash_d.insert(dummy, &i);
    }

    if (debug_level_d >= Integral::ALL) {
      context_hash_d.debug(L"dummy context hash table:");
    }
  }
  
  // exit gracefully
  //
  return true;
}

// method: getSubGraphIndex
//
// arguments:
//  const Context& context: (input) context containing symbol indices
//
// return: pointer to an index of the model of the input context
//
Ulong* SearchLevel::getSubGraphIndex(const Context& context_a) {
  return context_hash_d.get(context_a);
}