From Claudi Martinez:

add new tutorial


git-svn-id: http://root.cern.ch/svn/root/trunk@34697 27541ba8-7e3a-0410-8455-c3a389f83636

tutorials/fitsio/FITS_tutorial4.C

+// Open a FITS file whose primary array represents
+// a spectrum (flux vs wavelength)
+void FITS_tutorial4()
+{
+   printf("\n\n--------------------------------\n");
+   printf("WELCOME TO FITS tutorial #4 !!!!\n");
+   printf("--------------------------------\n");
+   printf("We're gonna open a FITS file that contains the\n");
+   printf("primary HDU and a little data table.\n");
+   printf("The data table is extension #1 and it has 2 rows.\n");
+   printf("We want to read only the rows that have the column\n");
+   printf("named DATAMAX greater than 2e-15 (there's only 1\n");
+   printf("matching row)\n");
+   printf("Data copyright: NASA\n\n");
+   
+   if (!gROOT->IsBatch()) {
+      printf("Press ENTER to start..."); getchar();
+   }
+    
+   //Open the table extension number 1)
+   TFITSHDU *hdu = new TFITSHDU("sample2.fits[1][DATAMAX > 2e-15]");
+   if (hdu == 0) {
+      printf("ERROR: could not access the HDU\n"); return;
+   }
+   printf("Press ENTER to see information about the table's columns..."); getchar();
+   hdu->Print("T");
+   
+   printf("\n\n........................................\n");
+   printf("Press ENTER to see full table contents (maybe you should resize\n");
+   printf("this window as large as possible before)..."); getchar();   
+   hdu->Print("T+");
+   
+   printf("\n\n........................................\n");
+   printf("Press ENTER to get only the DATAMAX value of the matched row..."); getchar();
+   TVectorD *v = hdu->GetTabRealVectorColumn("DATAMAX");
+   printf("%lg\n", (*v)[0]);
+   
+   
+   printf("Does the matched row have DATAMAX > 2e-15? :-)\n");
+   
+   //Clean up 
+   delete v;  
+   delete hdu;
+}
+
+ 
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