Data models

All functions in the processing function library should use these data models for the input and output variables. When referring to the dimensions (X, Y, Z) the Z dimension is the fastest varying while X is the slowest varying dimension.

Visibility functions

Functions which would be working with visibilities should use these input/outputs. Only parameters which are used be the function should be passed, not all of them.

• Visibilities: sdp_Mem *vis

  • Type: complex-valued array

  • Dimensions: (time samples, baselines, channels, polarizations)

• UVW coordinates: sdp_Mem *uvw [metres]

  • Type: real-valued array

  • Dimensions: (time samples, baselines, 3)

• Weights: sdp_Mem *weights

  • Type: real-valued array

  • Dimensions: (time samples, baselines, channels)

• Channel start: double channel_start [Hz]

  • Type: real-valued variable

• Channel step: double channel_step [Hz]

  • Type: real-valued array

• Time centroids: sdp_Mem *time_centroids [s]

  • Type: real-valued array

  • Dimensions: (time samples, baselines, channels)

• Freq centroids: sdp_Mem *freq_centroid [Hz]

  • Type: real-valued array

  • Dimensions: (time samples, baselines, channels)

• Exposure: sdp_Mem *exposure [s]

  • Type: real-valued array

  • Dimensions: (time samples, baselines, channels)

• Bandwidth: sdp_Mem *bandwidth [Hz]

  • Type: real-valued array

  • Dimensions: (time samples, baselines, channels)

• Sky Coordinate Metadata: sdp_SkyCoord *coord

  • Type: SkyCoord contains a string (char* type) to describe the coordinate type, a coordinate epoch (double), and up to three values coord1, coord2, coord3 (each a double).

• Baseline metadata: sdp_Table *bl

  • Note: table-like data type not implemented yet

• Polarisation metadata: sdp_Table *polar

  • Note: table-like data type not implemented yet

• Scan id: sdp_Mem *scan_id

  • Type: integer-valued array

  • Dimensions: (time samples)

• Scan metadata: sdp_Table *scan

  • Note: table-like data type not implemented yet

Grid functions

Functions which would be working on grids should use these input/outputs. Only parameters which are used be the function should be passed, not all of them.

• Grid: sdp_Mem *grid

  • Type: complex-valued array

  • Dimensions: (channels, w, v, u, polarizations)

• Coordinate step: double du, double dv, double dw

  • Type: real-valued

• Grid offset: double offset_u, double offset_v, double offset_w

  • Type: real-valued

• Sky Coordinate Metadata: sdp_SkyCoord *coord

  • Type: SkyCoord contains a string (char* type) to describe the coordinate type, a coordinate epoch (double), and up to three values coord1, coord2, coord3 (each a double).

• UVW Projection: sdp_Mem *uvw_projection

  • Type: real-valued

  • Dimensions: (3, 3)

• Polarisation metadata: sdp_Table *polar

  • Note: table-like data type not implemented yet

UVW functions

Functions which would be working on UVW coordinates should use these input/outputs. Only parameters which are used be the function should be passed, not all of them.

• UVW coordinates: sdp_Mem *uvw

  • Type: real-valued array

  • Dimensions: (time samples, baselines, 3)

• Time: double time_start, double time_step

  • Type: real-valued

• Sky Coordinate Metadata: sdp_SkyCoord *coord

  • Type: SkyCoord contains a string (char* type) to describe the coordinate type, a coordinate epoch (double), and up to three values coord1, coord2, coord3 (each a double).

• UVW Projection: sdp_Mem *uvw_projection

  • Type: real-valued

  • Dimensions: (3, 3)

• Baseline metadata: sdp_Table *bl

  • Note: table-like data type not implemented yet

Image functions

Functions which would be working on UVW coordinates should use these input/outputs. Only parameters which are used be the function should be passed, not all of them.

• Image: sdp_Mem *image

  • Type: complex-valued array

  • Dimensions: (channels, m, l, polarizations)

• Coordinate step: double dl, double dm

  • Type: real-valued

• Sky Coordinate Metadata: sdp_SkyCoord *coord

  • Type: SkyCoord contains a string (char* type) to describe the coordinate type, a coordinate epoch (double), and up to three values coord1, coord2, coord3 (each a double).

• lmn projection: sdp_Mem *lmn_projection

  • Type: real-valued

  • Dimensions: (3, 3)

• Polarisation metadata: sdp_Table *polar

  • Note: table-like data type not implemented yet