## functions in drat.i - i

integ_flat

integ_flat(opac, source, rays, mesh, slimits) or integ_flat(opac, source, ray_paths) returns ngroup-by-2-by-nrays result, where result(,1,..) is the transparency factors, and result(,2,..) is the self-emission for each group on each ray. The input OPAC and SOURCE are the opacity (an inverse length) and the source function (a specific intensity). They are mesh-by-ngroups zone centered arrays. The result has the same units as SOURCE. In the second form, RAY_PATHS was returned by the track_rays function. Interpreted function, defined at i0/drat.i line 1111SEE ALSO: integ_linear, track_rays, form_mesh, streak, snap

integ_linear

integ_linear(opac, source, rays, mesh, slimits) or integ_linear(opac, source, ray_paths) returns ngroup-by-2-by-nrays result, where result(,1,..) is the transparency factors, and result(,2,..) is the self-emission for each group on each ray. The input OPAC and SOURCE are the opacity (an inverse length) and the source function (a specific intensity). They are mesh-by-ngroups arrays; OPAC is zone centered, while SOURCE is point centered (using pcen_source). The result has the same units as SOURCE. In the second form, RAY_PATHS was returned by the track_rays function. The integ_linear routine assumes that the SOURCE function varies linearly between the entry and exit points from each zone. This assumption is poor near the turning point, and causes the result to be a discontinuous function of the ray coordinates, unlike the integ_flat result. Interpreted function, defined at i0/drat.i line 1154SEE ALSO: pcen_source, integ_flat, track_rays, form_mesh, streak, snap

is_present

is_present(get_vars(f), name) returns 1 if variable NAME is present in file F, 0 if not. Interpreted function, defined at i0/drat.i line 891