visibility_set

API documentation for visibility_set.c.

Helper functions to do malloc-ing, filling, and free-ing of the visibility_set_t struct, which holds the outputs visiblities.

Author

J.L.B. Line

Functions

visibility_set_t *setup_visibility_set(int num_visis)

Create a visibility_set_t and return it with a number of arrays malloc-ed to the sizeof num_visis.

Mallocs num_visis*sizeof(user_precision_t) for the following arrays: 

visibility_set->us_metres
visibility_set->vs_metres
visibility_set->ws_metres
visibility_set->sum_visi_XX_real
visibility_set->sum_visi_XX_imag
visibility_set->sum_visi_XY_real
visibility_set->sum_visi_XY_imag
visibility_set->sum_visi_YX_real
visibility_set->sum_visi_YX_imag
visibility_set->sum_visi_YY_real
visibility_set->sum_visi_YY_imag

Returns:

visibility_set with a number of malloc-ed arrays

void fill_timefreq_visibility_set(visibility_set_t *visibility_set, woden_settings_t *woden_settings, double base_band_freq, double *lsts)

Fills in hour angle, LSTS, and wavelength/frequency information in visibility_set.

Mallocs and fills in the following arrays: 

visibility_set->allsteps_sha0s
visibility_set->allsteps_cha0s
visibility_set->allsteps_lsts
visibility_set->allsteps_wavelengths
visibility_set->channel_frequencies
Anything with allsteps will have a value for every baseline (fastest changing), every frequency, every time step (slowest changing). This makes it easy to injest into CUDA kernels as a single axis. channel_frequencies will list the frequencies in this ‘band’.

Parameters:

  • *visibility_set – [inout] A visibility_set_t to populate with arrays

  • *woden_settings – [in] Pointer to populated woden_settings_t struct containing simulation settings

  • base_band_freq – [in] The lowest frequency to simulate in this band

  • *lsts – [in] Array of LST for all time steps in the simulation

void write_visi_set_binary(visibility_set_t *visibility_set, int band_num, int num_visis)

Write out the simulated visibilities to a binary file.

Dumps u,v,w (metres), XX Real, XX Imag, XY Real, XY Imag, YX Real, YX Imag, YY Real, YY Imag (Jy) to a binary file Output order is by baseline (fastest changing), frequency, time (slowest changing). This means the us_metres, vs_metres, ws_metres are repeated over frequency, but keeps the dimensions of the output sane. Output is written as “output_visi_band%02d.dat”, band_num.

Parameters:

  • *visibility_set – [in] visibility_set_t populated with visibility data to be written out

  • band_num – [in] Number of the band being processed (used for output name

  • num_visis – [in] Number of visibilities to output

void write_visi_set_text(visibility_set_t *visibility_set, int band_num, woden_settings_t *woden_settings)

Write out XX visibilities and u,v,w to a text file.

Used for desperation debugging. Just writes u,v,w (metres), XX Real, XX Imag (Jy)

Parameters:

  • *visibility_set – [in] visibility_set_t populated with visibility data to be written out

  • band_num – [in] Number of the band being processed (used for output name

  • *woden_settings – [in] Populated woden_settings_t used to run the simulation

void free_visi_set_inputs(visibility_set_t *visibility_set)

Free the settings that were used for this visibility set.

We don’t free everything inside visibility_set as inside calculate_visibilitieswe set these arrays as pointers as don’t want to free the original allocation. This function frees: 

visibility_set->allsteps_sha0s
visibility_set->allsteps_cha0s
visibility_set->allsteps_lsts
visibility_set->allsteps_wavelengths
visibility_set->channel_frequencies

Parameters:

*visibility_set – [inout] Contains arrays that need freeing

void free_visi_set_outputs(visibility_set_t *visibility_set)

Free the output arrays in visibility_set

This function frees: 

visibility_set->us_metres
visibility_set->vs_metres
visibility_set->ws_metres
visibility_set->sum_visi_XX_real
visibility_set->sum_visi_XX_imag
visibility_set->sum_visi_XY_real
visibility_set->sum_visi_XY_imag
visibility_set->sum_visi_YX_real
visibility_set->sum_visi_YX_imag
visibility_set->sum_visi_YY_real
visibility_set->sum_visi_YY_imag

Parameters:

*visibility_set – [inout] Contains arrays that need freeing