man/man1/pvsum.1

.\" RCSid $Id: dctimestep.1,v 1.22 2025/03/24 17:20:36 greg Exp $"
.TH PVSUM 1 12/09/09 RADIANCE
.SH NAME
pvsum - sum component Radiance pictures based on vector or matrix
.SH SYNOPSIS
.B pvsum
[
.B "\-o ospec"
][
.B "\-o{f|c}
][
.B "\-N nproc"
]
.B ispec
[
.B mtx
]
.SH DESCRIPTION
.I Pvsum
is an efficient tool for summing Radiance pictures
into one or more output pictures.
Similar to
.I dctimestep(1),
multiple frames are produced if the input
.I mtx
has more than one column.
The number of rows in this matrix corresponds to the
number of component pictures specified in
.I ispec
with an incorporated "%d" or similar format string.
The first row in the matrix corresponds to picture 0, and
counting proceeds to one less than the number of matrix rows.
.PP
If no
.I mtx
is specified on the command line, the required data is read
from the standard input.
The input matrix
must either have a single component or match the number of components
in the input pictures, and the output pictures will match the latter component
count.
(I.e., grayscale float pictures have a component count of 1, RGB and XYZ
pictures a count of 3, and spectral pictures typically have 6 or more
components.)\0
.PP
By default, the output pixel type will match that of the input pictures,
either floating point or common-exponent byte format (i.e., RGBE, XYZE,
or Radiance_spectra).
If float output is preferred, specify the
.I \-of
option.
If common-exponent byte format is preferred, use the
.I \-oc
option.
.PP
If a
.I "\-o ospec"
argument begins with an exclamation point ('!') and contains a "%d"
format string or similar, then a separate command will be executed
for each output stream.
If no
.I \-o
option is given, all data is sent to the standard output,
which may be a sequence of Radiance pictures as understood by
.I ra_rgbe(1)
in the case of a multi-column input matrix.
(Note that there is currently no Radiance tool that understands a
concatenated series of float or spectral pictures.)\0
.PP
The
.I \-N
option may be used on Unix systems to specify the number of
processes to employ in the summations.
This setting has an upper limit equal to
the count of matrix columns, but
the optimal number of processes depends on several factors.
Setting the process count above the number of physical cores may
offer some benefit on large input collections if
their total size significantly exceeds the available system RAM.
Experimentation with this setting is therefore encouraged.
.SH EXAMPLES
To compute Window2's contribution to an interior view at 12 noon on the summer solstice:
.IP "" .2i
gensky 6 21 12 | genskyvec | rmtxop Blinds30.xml
Window2.dmx - | pvsum view%03d.hdr > view_6-21-12.hdr
.PP
To compute a set of hourly spectral pictures at SFO airport
from a weather tape and set of Tregenza component pictures:
.IP "" .2i
gensdaymtx sfo.epw | pvsum -o timestep%04d.hsr tregcomp%03d.hsr
.SH NOTES
This tool is annoyingly similar to
.I dctimestep,
but provides some important capabilities.
First,
.I pvsum
reads and can produce spectral pictures and matrices, whereas
.I dctimestep
expects and requires 3-component pictures and matrices throughout.
Changing the data structures in
.I dctimestep
proved too difficult and likely to
lead to a less efficient implementation, especially on systems with
limited memory.
In contrast,
.I pvsum
accelerates picture sums on Unix systems with more
memory and processint ability.
Second, operation was simplified by focusing on the Daylight Coefficient
command form, where the DC matrix is represented as a collection of
pictures.
By excluding the three or four other operation modes of
.I dctimestep,
new features could be explored in
.I pvsum.
For example, 
.I pvsum
can write picture data to a series of commands, which
.I dctimestep
does not support.
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
dcglare(1), dctimestep(1), gendaymtx(1), gensdaymtx(1), genskyvec(1), getinfo(1),
mkillum(1), ra_rgbe(1), rcollate(1), rcomb(1), rcontrib(1), rcrop(1),
rfluxmtx(1), rmtxop(1), rtrace(1), vwrays(1)
Revision:	1.1
Committed:	Thu Mar 27 01:26:55 2025 UTC (7 weeks, 3 days ago) by greg
Branch:	MAIN
Log Message:	feat(pvsum): Added new pvsum tool for spectral data, similar to dctimestep
#	User	Rev	Content
1	greg	1.1	.\" RCSid $Id: dctimestep.1,v 1.22 2025/03/24 17:20:36 greg Exp $"
2			.TH PVSUM 1 12/09/09 RADIANCE
3			.SH NAME
4			pvsum - sum component Radiance pictures based on vector or matrix
5			.SH SYNOPSIS
6			.B pvsum
7			[
8			.B "\-o ospec"
9			][
10			.B "\-o{f\|c}
11			][
12			.B "\-N nproc"
13			]
14			.B ispec
15			[
16			.B mtx
17			]
18			.SH DESCRIPTION
19			.I Pvsum
20			is an efficient tool for summing Radiance pictures
21			into one or more output pictures.
22			Similar to
23			.I dctimestep(1),
24			multiple frames are produced if the input
25			.I mtx
26			has more than one column.
27			The number of rows in this matrix corresponds to the
28			number of component pictures specified in
29			.I ispec
30			with an incorporated "%d" or similar format string.
31			The first row in the matrix corresponds to picture 0, and
32			counting proceeds to one less than the number of matrix rows.
33			.PP
34			If no
35			.I mtx
36			is specified on the command line, the required data is read
37			from the standard input.
38			The input matrix
39			must either have a single component or match the number of components
40			in the input pictures, and the output pictures will match the latter component
41			count.
42			(I.e., grayscale float pictures have a component count of 1, RGB and XYZ
43			pictures a count of 3, and spectral pictures typically have 6 or more
44			components.)\0
45			.PP
46			By default, the output pixel type will match that of the input pictures,
47			either floating point or common-exponent byte format (i.e., RGBE, XYZE,
48			or Radiance_spectra).
49			If float output is preferred, specify the
50			.I \-of
51			option.
52			If common-exponent byte format is preferred, use the
53			.I \-oc
54			option.
55			.PP
56			If a
57			.I "\-o ospec"
58			argument begins with an exclamation point ('!') and contains a "%d"
59			format string or similar, then a separate command will be executed
60			for each output stream.
61			If no
62			.I \-o
63			option is given, all data is sent to the standard output,
64			which may be a sequence of Radiance pictures as understood by
65			.I ra_rgbe(1)
66			in the case of a multi-column input matrix.
67			(Note that there is currently no Radiance tool that understands a
68			concatenated series of float or spectral pictures.)\0
69			.PP
70			The
71			.I \-N
72			option may be used on Unix systems to specify the number of
73			processes to employ in the summations.
74			This setting has an upper limit equal to
75			the count of matrix columns, but
76			the optimal number of processes depends on several factors.
77			Setting the process count above the number of physical cores may
78			offer some benefit on large input collections if
79			their total size significantly exceeds the available system RAM.
80			Experimentation with this setting is therefore encouraged.
81			.SH EXAMPLES
82			To compute Window2's contribution to an interior view at 12 noon on the summer solstice:
83			.IP "" .2i
84			gensky 6 21 12 \| genskyvec \| rmtxop Blinds30.xml
85			Window2.dmx - \| pvsum view%03d.hdr > view_6-21-12.hdr
86			.PP
87			To compute a set of hourly spectral pictures at SFO airport
88			from a weather tape and set of Tregenza component pictures:
89			.IP "" .2i
90			gensdaymtx sfo.epw \| pvsum -o timestep%04d.hsr tregcomp%03d.hsr
91			.SH NOTES
92			This tool is annoyingly similar to
93			.I dctimestep,
94			but provides some important capabilities.
95			First,
96			.I pvsum
97			reads and can produce spectral pictures and matrices, whereas
98			.I dctimestep
99			expects and requires 3-component pictures and matrices throughout.
100			Changing the data structures in
101			.I dctimestep
102			proved too difficult and likely to
103			lead to a less efficient implementation, especially on systems with
104			limited memory.
105			In contrast,
106			.I pvsum
107			accelerates picture sums on Unix systems with more
108			memory and processint ability.
109			Second, operation was simplified by focusing on the Daylight Coefficient
110			command form, where the DC matrix is represented as a collection of
111			pictures.
112			By excluding the three or four other operation modes of
113			.I dctimestep,
114			new features could be explored in
115			.I pvsum.
116			For example,
117			.I pvsum
118			can write picture data to a series of commands, which
119			.I dctimestep
120			does not support.
121			.SH AUTHOR
122			Greg Ward
123			.SH "SEE ALSO"
124			dcglare(1), dctimestep(1), gendaymtx(1), gensdaymtx(1), genskyvec(1), getinfo(1),
125			mkillum(1), ra_rgbe(1), rcollate(1), rcomb(1), rcontrib(1), rcrop(1),
126			rfluxmtx(1), rmtxop(1), rtrace(1), vwrays(1)