Open a FITS file whose primary array represents a spectrum (flux vs wavelength)
Author: Claudi Martinez
This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Friday, March 24, 2023 at 10:52 AM.
using Upvd_t = std::unique_ptr<TVectorD>;
We open a FITS file that contains a table with 9 rows and 8 columns. Column 4 has name 'mag' and contains a vector of 6 numeric components. The values of vectors in rows 1 and 2 (column 4) are: Row1: (99.0, 24.768, 23.215, 21.68, 21.076, 20.857) Row2: (99.0, 21.689, 20.206, 18.86, 18.32 , 18.128 ) WARNING: when coding, row and column indices start from 0
TString dir = gROOT->GetTutorialDir();
Open the table
TFITSHDU hdu(dir + "/fitsio/sample4.fits[1]");
Info in <TFITSHDU::LoadHDU>: The selected HDU contains a Table Extension
Read vectors at rows 1 and 2 (indices 0 and 1)
std::array<Upvd_t, 2> vs{Upvd_t(hdu.GetTabRealVectorCell(0, "mag")), Upvd_t(hdu.GetTabRealVectorCell(1, "mag"))};
for (auto &&v : vs) {
for(auto i : ROOT::TSeqI(v->GetNoElements())) {
if (i > 0)
printf(", ");
printf("%lg", (*v)[i]); // NOTE: the asterisk is for using the overloaded [] operator of the TVectorD object
}
printf(")\n");
}
// We now dump all rows using the function GetTabRealVectorCells()
std::unique_ptr<TObjArray> vectorCollection(hdu.GetTabRealVectorCells("mag"));
for (auto vObj : *vectorCollection) {
auto &v = *static_cast<TVectorD*>(vObj);
for (auto i : ROOT::TSeqI(v.GetNoElements())) {
if (i > 0) printf(", ");
printf("%lg", (v[i]));
}
printf(")\n");
}
99, 24.768, 23.215, 21.68, 21.076, 20.857) 99, 21.689, 20.206, 18.86, 18.32, 18.128) 99, 24.768, 23.215, 21.68, 21.076, 20.857) 99, 21.689, 20.206, 18.86, 18.32, 18.128) 99, 23.993, 22.575, 21.51, 21.07, 20.915) 99, 22.26, 20.717, 19.404, 18.888, 18.706) 99, 21.957, 20.41, 18.874, 18.271, 18.054) 99, 22.113, 20.535, 18.872, 18.229, 17.995) 99, 22.177, 20.678, 19.275, 18.714, 18.513) 99, 23.394, 21.846, 20.27, 19.649, 19.424) 99, 23.094, 21.452, 19.482, 18.723, 18.434)
Draw all canvases
gROOT->GetListOfCanvases()->Draw()