94 lines
3.0 KiB
C
94 lines
3.0 KiB
C
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#include <string.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "fitsio.h"
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/*
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This program illustrates how to use the CFITSIO iterator function.
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It reads and modifies the input 'iter_image.fit' image file by setting
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all the pixel values to zero (DESTROYING THE ORIGINAL IMAGE!!!)
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*/
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main()
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{
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extern zero_image(); /* external work function is passed to the iterator */
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fitsfile *fptr;
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iteratorCol cols[3]; /* structure used by the iterator function */
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int n_cols;
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long rows_per_loop, offset;
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int status, nkeys, keypos, hdutype, ii, jj;
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char filename[] = "iter_image.fit"; /* name of rate FITS file */
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status = 0;
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fits_open_file(&fptr, filename, READWRITE, &status); /* open file */
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n_cols = 1;
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/* define input column structure members for the iterator function */
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fits_iter_set_file(&cols[0], fptr);
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fits_iter_set_iotype(&cols[0], InputOutputCol);
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fits_iter_set_datatype(&cols[0], 0);
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rows_per_loop = 0; /* use default optimum number of rows */
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offset = 0; /* process all the rows */
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/* apply the rate function to each row of the table */
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printf("Calling iterator function...%d\n", status);
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fits_iterate_data(n_cols, cols, offset, rows_per_loop,
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zero_image, 0L, &status);
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fits_close_file(fptr, &status); /* all done */
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if (status)
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fits_report_error(stderr, status); /* print out error messages */
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return(status);
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}
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/*--------------------------------------------------------------------------*/
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int zero_image(long totalrows, long offset, long firstrow, long nrows,
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int ncols, iteratorCol *cols, void *user_strct )
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/*
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Sample iterator function that calculates the output flux 'rate' column
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by dividing the input 'counts' by the 'time' column.
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It also applies a constant deadtime correction factor if the 'deadtime'
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keyword exists. Finally, this creates or updates the 'LIVETIME'
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keyword with the sum of all the individual integration times.
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*/
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{
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int ii, status = 0;
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/* declare variables static to preserve their values between calls */
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static int *counts;
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/*--------------------------------------------------------*/
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/* Initialization procedures: execute on the first call */
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/*--------------------------------------------------------*/
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if (firstrow == 1)
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{
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if (ncols != 1)
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return(-1); /* number of columns incorrect */
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/* assign the input pointers to the appropriate arrays and null ptrs*/
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counts = (int *) fits_iter_get_array(&cols[0]);
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}
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/*--------------------------------------------*/
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/* Main loop: process all the rows of data */
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/*--------------------------------------------*/
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/* NOTE: 1st element of array is the null pixel value! */
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/* Loop from 1 to nrows, not 0 to nrows - 1. */
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for (ii = 1; ii <= nrows; ii++)
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{
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counts[ii] = 1.;
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}
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printf("firstrows, nrows = %d %d\n", firstrow, nrows);
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return(0); /* return successful status */
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}
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