C++ NcVar类代码示例

//TODO optimize this thing
void writeResultsFile(string dataFileName, string yDimension, vector<double> * pValues)
{
    NcFile file(dataFileName.c_str(), NcFile::ReadOnly);
    NcVar *geneNames = file.get_var("gene");
    int dataYsize = file.get_dim(yDimension.c_str())->size();

    FILE * pFile;
    pFile = fopen ("results.txt","w");

    cout << "Writing results to file.." << endl;

    int percentage = dataYsize / 10;
    int percentageCount = 10;
    for(int i = 0; i < dataYsize; i++){
        char * c = geneNames->as_string(i*28);
        std::string str;
        if(pValues->at(i) > 0.05){
            std::ostringstream strs;
            strs << pValues->at(i);
            str = strs.str();
        }else{
            str = "NA";
        }
        fprintf (pFile, "%-20s-%20s", c, str.c_str());
        fprintf (pFile, "\n");
        if(i == percentage)
        {
            cout <<  percentageCount << "% complete" << endl;
            percentageCount += 10;
            percentage += dataYsize / 10;
        }
        delete c;
    }
    fclose(pFile);
}

FieldPtr FileArome::getFieldCore(std::string iVariable, int iTime) const {
   // Not cached, retrieve data
   NcVar* var = getVar(iVariable);
   int nLat  = mNLat;
   int nLon  = mNLon;

   int numDims = var->num_dims();

   long* count;
   long totalCount = nLat*nLon;
   if(numDims == 4) {
      // Variable has a surface dimension
      count = new long[4];
      count[0] = 1;
      count[1] = 1;
      count[2] = nLat;
      count[3] = nLon;
      var->set_cur(iTime, 0, 0, 0);
   }
   else if(numDims == 3) {
      count = new long[3];
      count[0] = 1;
      count[1] = nLat;
      count[2] = nLon;
      var->set_cur(iTime, 0, 0);
   }
   else {
      std::stringstream ss;
      ss << "Cannot read variable '" << iVariable << "' from '" << getFilename() << "'";
      Util::error(ss.str());
   }
   float* values = new float[nLat*nLon];
   var->get(values, count);
   float MV = getMissingValue(var);

   float offset = getOffset(var);
   float scale = getScale(var);
   int index = 0;
   FieldPtr field = getEmptyField();
   for(int lat = 0; lat < nLat; lat++) {
      for(int lon = 0; lon < nLon; lon++) {
         float value = values[index];
         assert(index < totalCount);
         if(value == MV) {
            // Field has missing value indicator and the value is missing
            // Save values using our own internal missing value indicator
            value = Util::MV;
         }
         else {
            value = scale*values[index] + offset;
         }
         (*field)(lat,lon,0) = value;
         index++;
      }
   }
   delete[] values;
   delete[] count;
   return field;
}

int NetcdfSource::readScalar(double *v, const QString& field)
{
  // TODO error handling
  QByteArray bytes = field.toLatin1();
  NcVar *var = _ncfile->get_var(bytes.constData());  // var is owned by _ncfile
  var->get(v);
  return 1;
}

void NetCdfConfigureDialog::setVariableSelect()
{
    for (int i=0; i<(_currentFile->num_vars()); i++)
    {
        NcVar *focusedVar = _currentFile->get_var(i);
        if (focusedVar->num_dims() > 0) comboBoxVariable->addItem(focusedVar->name());
    }
}

 Var( const NcVar* var ):
     m_var( var )
 {
     const int ndims = m_var->num_dims();
     for ( int i = 0; i < ndims; i++ )
     {
         m_dims.push_back( new Dim( m_var->get_dim(i) ) );
     }
 }

std::vector<T> read_vector(NcFile &nc, std::string const &var_name)
{
	// Read points vector
	NcVar *vpoints = nc.get_var(var_name.c_str());
	long npoints = vpoints->get_dim(0)->size();
	std::vector<T> points(npoints);
	vpoints->get(&points[0], npoints);
	return points;
}

void DumpableNcFile::dumpdata( )
{
    NcVar* vp;
    for (int n = 0; vp = get_var(n); n++) {
	cout << " " << vp->name() << " = ";
	NcValues* vals = vp->values();
	cout << *vals << " ;" << endl ;
	delete vals;
    }
}

bool ReadAstro::open(const char *path)
{
    assert(!m_ncfile);
    m_ncfile = new NcFile(path, NcFile::ReadOnly);
    if (!m_ncfile->is_valid())
    {
        close();
        sendError("failed to open NetCDF file %s", path);
        return false;
    }

    if (m_ncfile->get_format() == NcFile::BadFormat)
    {
        close();
        sendError("bad NetCDF file");
        return false;
    }

    fprintf(stderr, "dims=%d, vars=%d, attrs=%d\n",
            m_ncfile->num_dims(), m_ncfile->num_vars(), m_ncfile->num_atts());

    for (int i = 0; i < m_ncfile->num_dims(); ++i)
    {
        fprintf(stderr, "%s: %ld\n",
                m_ncfile->get_dim(i)->name(),
                m_ncfile->get_dim(i)->size());
    }

    for (int i = 0; i < m_ncfile->num_vars(); ++i)
    {
        fprintf(stderr, "%s: dims=%d atts=%d vals=%ld type=%d\n",
                m_ncfile->get_var(i)->name(),
                m_ncfile->get_var(i)->num_dims(),
                m_ncfile->get_var(i)->num_atts(),
                m_ncfile->get_var(i)->num_vals(),
                m_ncfile->get_var(i)->type());
        //int dims = m_ncfile->get_var(i)->num_dims();
        NcVar *var = m_ncfile->get_var(i);
        for (int j = 0; j < var->num_dims(); ++j)
        {
            fprintf(stderr, "   %s: %ld edge=%ld\n",
                    var->get_dim(j)->name(),
                    var->get_dim(j)->size(),
                    var->edges()[j]);
        }
    }

    for (int i = 0; i < m_ncfile->num_atts(); ++i)
    {
        fprintf(stderr, "%s\n", m_ncfile->get_att(i)->name());
    }

    return true;
}

vector<string>
eavlNetCDFImporter::GetFieldList(const string &mesh)
{
    vector<string> retval;
    for (unsigned int v=0; v<vars.size(); v++)
    {
        NcVar *var = vars[v];
        retval.push_back(var->name());
    }
    return retval;
}

int NetcdfSource::samplesPerFrame(const QString& field) {
  if (field.toLower() == "index") {
    return 1;
  }
  QByteArray bytes = field.toLatin1();
  NcVar *var = _ncfile->get_var(bytes.constData());
  if (!var) {
    return 0;
  }
  return var->rec_size();
}

int NetCdfConfigureDialog::getTimeStep()
{
    NcVar* timeVar = _currentFile->get_var(comboBoxDim2->currentIndex());

    const double datesToMinutes = convertDateToMinutes(_currentInitialDateTime,dateTimeEditDim3->date(),dateTimeEditDim3->time());

    double timeArray[1] = {datesToMinutes};
    double currentTime = timeVar->get_index(timeArray);
    if (currentTime < 0) currentTime=0; //if the value isn't found in the array, set it to 0 as default...
    return currentTime;
}

void dumpatts(NcVar& var)
{
    NcToken vname = var.name();
    NcAtt* ap;
    for(int n = 0; ap = var.get_att(n); n++) {
	cout << "\t\t" << vname << ":" << ap->name() << " = " ;
	NcValues* vals = ap->values();
	cout << *vals << " ;" << endl ;
	delete ap;
	delete vals;
    }
}

int main(int argc, char *argv[])
{
    NcFile at(atpath, NcFile::ReadOnly);
    if(!at.is_valid() || at.num_dims() != 3 || at.num_vars() != 4) {
        fprintf(stderr, "failed reading file: %s\n", atpath);
        return 1;
    }

    NcVar* data = at.get_var("rhum");
    if(!data->is_valid() || data->num_dims() != 3) {
        fprintf(stderr, "rhum has incorrect dimensions");
        return 1;
    }

    NcDim* time = data->get_dim(0);
    int timecnt = time->size();
    float  *rhumd = new float[timecnt*LATS*LONS];
    data->get(rhumd, timecnt, LATS, LONS);

    float  rhumdmon[12][LATS][LONS];
    for(int i = 0; i<LATS; i++)
        for(int j = 0; j<LONS; j++) {
            float rhumdmoncnt[12];
            for(int k = 0; k<12; k++) {
                rhumdmon[k][i][j] = 0;
                rhumdmoncnt[k] = 0;
            }
            for(int k = 0; k<timecnt; k++) {
                double v = rhumd[(k*LATS+i)*LONS+j]*.1 + 3276.5;
                if(v >= 0 && v <= 100) {
                    rhumdmon[k%12][i][j] += v;
                    rhumdmoncnt[k%12]++;
                }
            }
            for(int k = 0; k<12; k++)
                rhumdmon[k][i][j] /= rhumdmoncnt[k];
        }
    delete [] rhumd;

    /* use a single byte instead of 2 to save memory,
       resolution of 1/5th of a mm/day resolution */
    uint8_t rhumbyte[12][LATS][LONS];
    for(int i = 0; i<12; i++)
        for(int j = 0; j<LATS; j++)
            for(int k = 0; k<LONS; k++)
                if(isnan(rhumdmon[i][j][k]) || fabs(rhumdmon[i][j][k]) > 100)
                    rhumbyte[i][j][k] = 255;
                else
                    rhumbyte[i][j][k] = rhumdmon[i][j][k]*2.0;
    
    fwrite(rhumbyte, sizeof rhumbyte, 1, stdout);
    return 0;
}

void ConstantSet::read_from_netcdf(NcFile &nc, std::string const &vname)
{
	NcVar *ncvar = giss::get_var_safe(nc, vname.c_str(), true);
	if (!ncvar) {
		fprintf(stderr, "ConstantSet::read_from_netcdf() cannot find variable %s\n", vname.c_str());
		throw std::exception();
	}
	int n = ncvar->num_atts();

	// Read through the attributes, getting units and names separately
	std::map<std::string, std::string> units;
	std::map<std::string, double> consts;
	std::map<std::string, std::string> descriptions;
	for (int i=0; i<n; ++i) {
		auto att = giss::get_att(ncvar, i);
		std::string att_name(att->name());
		if (giss::ends_with(att_name, "_description")) {
			descriptions.insert(std::make_pair(
				att_name.substr(0, att_name.size() - std::strlen("_description")),
				std::string(att->as_string(0))));
		} else if (giss::ends_with(att_name, "_units")) {
			units.insert(std::make_pair(
				att_name.substr(0, att_name.size() - std::strlen("_units")),
				std::string(att->as_string(0))));
		} else {
			consts.insert(std::make_pair(
				att_name, att->as_double(0)));
		}
	}

	// Now go through them again, matching up constants and units
	for (auto ii = consts.begin(); ii != consts.end(); ++ii) {
		std::string const &name = ii->first;
		double const val = ii->second;

		auto ui = units.find(name);
		if (ui == units.end()) {
			fprintf(stderr, "Could not find _units attribute for %s\n", name.c_str());
		}

		auto di = descriptions.find(name);
		if (di == descriptions.end()) {
			fprintf(stderr, "Could not find _description attribute for %s\n", name.c_str());
		}

		std::string const &u = units.find(name)->second;
		std::string const &d = descriptions.find(name)->second;

		set(name, val, u, d);
	}
}

int 
main(void)
@{
   // This is the data array we will write. It will just be filled
   // with a progression of numbers for this example.
   int dataOut[NX][NY];
  
   // Create some pretend data. If this wasn't an example program, we
   // would have some real data to write, for example, model output.
   for(int i = 0; i < NX; i++) 
      for(int j = 0; j < NY; j++)
	 dataOut[i][j] = i * NY + j;

   // Create the file. The Replace parameter tells netCDF to overwrite
   // this file, if it already exists.
   NcFile dataFile("simple_xy.nc", NcFile::Replace);

   // You should always check whether a netCDF file creation or open
   // constructor succeeded.
   if (!dataFile.is_valid())
   @{
      cout << "Couldn't open file!\n";
      return NC_ERR;
   @}
  
   // For other method calls, the default behavior of the C++ API is
   // to exit with a message if there is an error.  If that behavior
   // is OK, there is no need to check return values in simple cases
   // like the following.

   // When we create netCDF dimensions, we get back a pointer to an
   // NcDim for each one.
   NcDim* xDim = dataFile.add_dim("x", NX);
   NcDim* yDim = dataFile.add_dim("y", NY);
  
   // Define a netCDF variable. The type of the variable in this case
   // is ncInt (32-bit integer).
   NcVar *data = dataFile.add_var("data", ncInt, xDim, yDim);
     
   // Write the pretend data to the file. Although netCDF supports
   // reading and writing subsets of data, in this case we write all
   // the data in one operation.
   data->put(&dataOut[0][0], NX, NY);

   // The file will be automatically close when the NcFile object goes
   // out of scope. This frees up any internal netCDF resources
   // associated with the file, and flushes any buffers.
   cout << "*** SUCCESS writing example file simple_xy.nc!" << endl;

   return 0;
@}