man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.24 2023/11/21 02:16:59 greg Exp $"
.TH RMTXOP 1 5/31/2014 RADIANCE
.SH NAME
rmtxop - concatenate, add, multiply, divide, transpose, scale, and convert matrices
.SH SYNOPSIS
.B rmtxop
[
.B \-v
][
.B \-f[afdc]
][
.B \-t
][
.B "\-c ce .."
][
.B "\-s sf .."
][
.B "\-rf|\-rb"
]
.B m1
[
.B ".+*/"
]
.B ".."
.SH DESCRIPTION
.I Rmtxop
loads and concatenates or adds/multiplies/divides
together component matrix files given on the command line.
Each file must have a header containing the following variables:
.sp
.nf
NROWS={number of rows}
NCOLS={number of columns}
NCOMP={number of components}
FORMAT={ascii|float|double|32-bit_rle_rgbe|32-bit_rle_xyze|Radiance_spectra}
.fi
.sp
The number of components indicates that each matrix element is actually
composed of multiple elements, most commonly an RGB triple.
This is essentially dividing the matrix into planes, where each component
participates in a separate calculation.
If an appropriate header is not present, it may be added with a call to
.I rcollate(1).
A matrix may be read from the standard input using a hyphen by itself ('-')
in the appropriate place on the command line.
.PP
Any of the matrix inputs may be read from a command
instead of a file by
using quotes and a beginning exclamation point ('!').
.PP
Two special cases are handled for component matrices that are either
XML files containing BSDF data, or Radiance picture files.
In the first case, the BSDF library loads and interprets the
transmission matrix by default.
Alternatively, the front (normal-side) reflectance is selected if the
.I \-rf
option precedes the file name, or the backside reflectance if
.I \-rb
is specified.
(XML files cannot be read from the standard input or from a command.)\0
In the second case, the RGBE or XYZE values are loaded in a 3-component
matrix where the number of columns match the X-dimension of the picture, and
the number of rows match the Y-dimension.
The picture must be in standard pixel ordering, and the first row
is at the top with the first column on the left.
Any exposure changes that were applied to the pictures before
.I rmtxop
will be undone, similar to the
.I pcomb(1)
.I \-o
option.
Radiance spectral pictures with more than 3 components are also supported.
These are typically produced by
.I rtrace(1)
or
.I rfluxmtx(1).
.PP
Before each file, the
.I \-t
and
.I \-c
and/or
.I \-s
options may be used to modify the matrix.
The
.I \-t
option transposes the matrix, swapping rows and columns.
The
.I \-c
option can "transform" the element values, possibly changing
the number of components in the matrix.
For example, a 3-component matrix can be transformed into a single-component
matrix by using
.I \-c
with three coefficients.
A four-component matrix can be turned into a two-component matrix using 8
coefficients, where the first four coefficients will be used to compute
the first new component, and the second four coefficients
yield the second new component.
Note that the number of coefficients must be an even multiple of the number
of original components.
Alternatively, a set of symbolic output components can be specified as capital
letters, with the following definitions:
.sp
.nf
R       - red channel
G       - green channel
B       - blue channel
X       - CIE X channel
Y       - CIE Y channel (aka., luminance or illuminance)
Z       - CIE Z channel
S       - scotopic luminance or illuminance
M       - melanopic luminance or illuminance
.fi
.sp
These letters may be given in any order as a single string, and if
.I "-c RGB"
or
.I "-c XYZ"
is specified along with a
.I "-fc"
option, the output will be written as a RGBE or XYZE picture, respectively.
Note that conversion from a float or RGBE color space applies a conversion
of 179 lumens/watt (for CIE or melanopic output) or 412 (for scotopic output),
and the reverse happens for conversion from XYZE input to RGB or RGBE output.
.PP
Additionally, the
.I \-s
option applies the given scalar factor(s) to the elements of the matrix.
If only one factor is provided,
it will be used for all components.
If multiple factors are given, their number must match the number of matrix
components
.I after
application of any
.I \-c
option for this input matrix or picture.
.PP
If present, the second and subsequent matrices on the command
line are concatenated together, unless separated by a plus ('+'),
asterisk ('*'), or forward slash ('/') symbol,
in which case the individual matrix elements are added,
multiplied, or divided, respectively.
The concatenation operator ('.') is the default and need not be specified.
Note also that the asterisk must be quoted or escaped in most shells.
In the case of addition, the two matrices involved must have the same number
of components.
If subtraction is desired, use addition ('+') with a scaling parameter of -1
for the second matrix (the
.I \-s
option).
For element-wise multiplication and division, the second matrix is
permitted to have a single component per element, which will be
applied equally to all components of the first matrix.
If element-wise division is specified, any zero elements in the second
matrix will result in a warning and the corresponding component(s) in the
first matrix will be set to zero.
.PP
Evaluation proceeds from left to right, and all operations have
the same precedence.
If a different evaluation order is desired, pipe the result of one
.I rmtxop
command into another, as shown in one of the examples below.
.PP
The number of components in the next matrix after applying any
.I -c
transform must agree with the prior result.
For concatenation (matrix multiplication), the number of columns
in the prior result must equal the number of rows in the next matrix, and
the result will have the number of rows of the previous and the number
of columns of the next matrix.
In the case of addition, multiplication, and division,
the number of rows and columns of the prior result and the
next matrix must match, and will not be changed by the operation.
.PP
A final transpose or transform/scaling operation may be applied to
the results by appending the
.I \-t
and
.I \-c
and/or
.I \-s
options after the last matrix on the command line.
.PP
Results are sent to the standard output.
By default, the values will be written in the lowest resolution format
among the inputs, but the
.I \-f
option may be used to explicitly output components
as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent
colors/spectra (-fc).
In the latter case, the actual matrix dimensions are written in the resolution
string rather than the header.
Also, matrix results will be written as standard
Radiance pictures if they have either one
or three components.
In the one-component case, the output is written as grayscale.
If more than 3 components are in the final matrix and
.I -fc
is specified, the output will be a Radiance spectral picture.
.PP
The
.I \-v
option turns on verbose reporting, which announces each operation.
.SH EXAMPLES
To concatenate two matrix files with a BTDF between them and write
the result as binary double:
.IP "" .2i
rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
.PP
To convert a BTDF matrix into a Radiance picture:
.IP "" .2i
rmtxop -fc blinds.xml > blinds.hdr
.PP
To extract the luminance values from a picture as an ASCII matrix:
.IP "" .2i
rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
.PP
To render a melanopic illuminance image with
.I rtrace\:
.IP "" .2i
vwrays -ff -x 1024 -y 1024 -vf myview.vf |
rtrace -fff -cs 18 -co+ -i+ `vwrays -x 1024 -y 1024 -vf myview.vf -d` scene.oct |
rmtxop -fc -c M - > scene_meli.hdr
.PP
To scale a matrix by 4 and add it to the transpose of another matrix:
.IP "" .2i
rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
.PP
To multiply elements of two matrices, then concatenate with a third,
applying a final transpose to the result:
.IP "" .2i
rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
.PP
To left-multiply the element-wise division of two matrices:
.IP "" .2i
rmtxop -fd numerator.mtx / denominator.mtx | rmtxop left.mtx - > result.mtx
.PP
To send the elements of a binary matrix to 
.I rcalc(1)
for further processing:
.IP "" .2i
rmtxop -fa orig.mtx | rcollate -ho -oc 1 | rcalc [operations]
.SH NOTES
Matrix concatenation is associative but not commutative, so order
matters to the result.
.I Rmtxop
takes advantage of this associative property to concatenate
from right to left when it reduces the number of basic operations.
If the rightmost matrix is a column vector for example, it is
much faster to concatenate from the right, and the result will
be the same.
Note that this only applies to concatenation;
element-wise addition, multiplication, and division are always
evaluated from left to right.
.SH AUTHOR
Greg Ward
.SH "SEE ALSO"
cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1),
ra_xyze(1), rcalc(1),
rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), rlam(1), 
rsplit(1), rtrace(1), tabfunc(1), total(1), vwrays(1),
wrapBSDF(1)
Revision:	1.25
Committed:	Mon Nov 27 22:04:45 2023 UTC (17 months, 3 weeks ago) by greg
Branch:	MAIN
Changes since 1.24:	+57 -24 lines
Log Message:	feat(rmtxop): Added symbolic transforms to -c option and made -s apply after any such transform, so both may be used simultaneously
#	User	Rev	Content
1	greg	1.25	.\" RCSid "$Id: rmtxop.1,v 1.24 2023/11/21 02:16:59 greg Exp $"
2	greg	1.23	.TH RMTXOP 1 5/31/2014 RADIANCE
3	greg	1.1	.SH NAME
4	greg	1.10	rmtxop - concatenate, add, multiply, divide, transpose, scale, and convert matrices
5	greg	1.1	.SH SYNOPSIS
6			.B rmtxop
7			[
8			.B \-v
9			][
10	greg	1.3	.B \-f[afdc]
11	greg	1.1	][
12			.B \-t
13			][
14	greg	1.25	.B "\-c ce .."
15			][
16	greg	1.1	.B "\-s sf .."
17			][
18	greg	1.22	.B "\-rf\|\-rb"
19	greg	1.1	]
20			.B m1
21			[
22	greg	1.13	.B ".+*/"
23	greg	1.1	]
24			.B ".."
25			.SH DESCRIPTION
26			.I Rmtxop
27	greg	1.10	loads and concatenates or adds/multiplies/divides
28			together component matrix files given on the command line.
29	greg	1.1	Each file must have a header containing the following variables:
30			.sp
31			.nf
32			NROWS={number of rows}
33			NCOLS={number of columns}
34			NCOMP={number of components}
35	greg	1.24	FORMAT={ascii\|float\|double\|32-bit_rle_rgbe\|32-bit_rle_xyze\|Radiance_spectra}
36	greg	1.25	.fi
37	greg	1.1	.sp
38			The number of components indicates that each matrix element is actually
39			composed of multiple elements, most commonly an RGB triple.
40			This is essentially dividing the matrix into planes, where each component
41			participates in a separate calculation.
42			If an appropriate header is not present, it may be added with a call to
43			.I rcollate(1).
44			A matrix may be read from the standard input using a hyphen by itself ('-')
45			in the appropriate place on the command line.
46			.PP
47	greg	1.9	Any of the matrix inputs may be read from a command
48			instead of a file by
49			using quotes and a beginning exclamation point ('!').
50			.PP
51	greg	1.1	Two special cases are handled for component matrices that are either
52	greg	1.20	XML files containing BSDF data, or Radiance picture files.
53			In the first case, the BSDF library loads and interprets the
54			transmission matrix by default.
55			Alternatively, the front (normal-side) reflectance is selected if the
56			.I \-rf
57			option precedes the file name, or the backside reflectance if
58			.I \-rb
59			is specified.
60	greg	1.9	(XML files cannot be read from the standard input or from a command.)\0
61	greg	1.1	In the second case, the RGBE or XYZE values are loaded in a 3-component
62			matrix where the number of columns match the X-dimension of the picture, and
63			the number of rows match the Y-dimension.
64			The picture must be in standard pixel ordering, and the first row
65	greg	1.7	is at the top with the first column on the left.
66	greg	1.21	Any exposure changes that were applied to the pictures before
67	greg	1.18	.I rmtxop
68			will be undone, similar to the
69	greg	1.19	.I pcomb(1)
70	greg	1.18	.I \-o
71			option.
72	greg	1.24	Radiance spectral pictures with more than 3 components are also supported.
73			These are typically produced by
74			.I rtrace(1)
75			or
76			.I rfluxmtx(1).
77	greg	1.1	.PP
78			Before each file, the
79			.I \-t
80			and
81	greg	1.25	.I \-c
82			and/or
83	greg	1.1	.I \-s
84			options may be used to modify the matrix.
85			The
86			.I \-t
87			option transposes the matrix, swapping rows and columns.
88			The
89			.I \-c
90	greg	1.25	option can "transform" the element values, possibly changing
91	greg	1.1	the number of components in the matrix.
92			For example, a 3-component matrix can be transformed into a single-component
93			matrix by using
94			.I \-c
95			with three coefficients.
96			A four-component matrix can be turned into a two-component matrix using 8
97			coefficients, where the first four coefficients will be used to compute
98			the first new component, and the second four coefficients
99			yield the second new component.
100			Note that the number of coefficients must be an even multiple of the number
101			of original components.
102	greg	1.25	Alternatively, a set of symbolic output components can be specified as capital
103			letters, with the following definitions:
104			.sp
105			.nf
106			R - red channel
107			G - green channel
108			B - blue channel
109			X - CIE X channel
110			Y - CIE Y channel (aka., luminance or illuminance)
111			Z - CIE Z channel
112			S - scotopic luminance or illuminance
113			M - melanopic luminance or illuminance
114			.fi
115			.sp
116			These letters may be given in any order as a single string, and if
117			.I "-c RGB"
118			or
119			.I "-c XYZ"
120			is specified along with a
121			.I "-fc"
122			option, the output will be written as a RGBE or XYZE picture, respectively.
123			Note that conversion from a float or RGBE color space applies a conversion
124			of 179 lumens/watt (for CIE or melanopic output) or 412 (for scotopic output),
125			and the reverse happens for conversion from XYZE input to RGB or RGBE output.
126			.PP
127			Additionally, the
128	greg	1.1	.I \-s
129	greg	1.25	option applies the given scalar factor(s) to the elements of the matrix.
130			If only one factor is provided,
131			it will be used for all components.
132			If multiple factors are given, their number must match the number of matrix
133			components
134			.I after
135			application of any
136	greg	1.1	.I \-c
137	greg	1.25	option for this input matrix or picture.
138	greg	1.1	.PP
139			If present, the second and subsequent matrices on the command
140	greg	1.16	line are concatenated together, unless separated by a plus ('+'),
141	greg	1.10	asterisk ('*'), or forward slash ('/') symbol,
142	greg	1.15	in which case the individual matrix elements are added,
143	greg	1.16	multiplied, or divided, respectively.
144			The concatenation operator ('.') is the default and need not be specified.
145			Note also that the asterisk must be quoted or escaped in most shells.
146	greg	1.10	In the case of addition, the two matrices involved must have the same number
147			of components.
148	greg	1.15	If subtraction is desired, use addition ('+') with a scaling parameter of -1
149			for the second matrix (the
150			.I \-s
151			option).
152	greg	1.11	For element-wise multiplication and division, the second matrix is
153	greg	1.15	permitted to have a single component per element, which will be
154	greg	1.11	applied equally to all components of the first matrix.
155	greg	1.10	If element-wise division is specified, any zero elements in the second
156			matrix will result in a warning and the corresponding component(s) in the
157			first matrix will be set to zero.
158			.PP
159	greg	1.16	Evaluation proceeds from left to right, and all operations have
160			the same precedence.
161			If a different evaluation order is desired, pipe the result of one
162			.I rmtxop
163			command into another, as shown in one of the examples below.
164			.PP
165	greg	1.17	The number of components in the next matrix after applying any
166	greg	1.1	.I -c
167			transform must agree with the prior result.
168			For concatenation (matrix multiplication), the number of columns
169	greg	1.17	in the prior result must equal the number of rows in the next matrix, and
170	greg	1.1	the result will have the number of rows of the previous and the number
171	greg	1.17	of columns of the next matrix.
172	greg	1.10	In the case of addition, multiplication, and division,
173			the number of rows and columns of the prior result and the
174	greg	1.17	next matrix must match, and will not be changed by the operation.
175	greg	1.1	.PP
176	greg	1.25	A final transpose or transform/scaling operation may be applied to
177	greg	1.14	the results by appending the
178			.I \-t
179			and
180	greg	1.25	.I \-c
181			and/or
182	greg	1.14	.I \-s
183			options after the last matrix on the command line.
184			.PP
185	greg	1.1	Results are sent to the standard output.
186	greg	1.4	By default, the values will be written in the lowest resolution format
187	greg	1.6	among the inputs, but the
188	greg	1.1	.I \-f
189	greg	1.4	option may be used to explicitly output components
190	greg	1.25	as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent
191			colors/spectra (-fc).
192	greg	1.1	In the latter case, the actual matrix dimensions are written in the resolution
193			string rather than the header.
194	greg	1.24	Also, matrix results will be written as standard
195			Radiance pictures if they have either one
196	greg	1.1	or three components.
197			In the one-component case, the output is written as grayscale.
198	greg	1.24	If more than 3 components are in the final matrix and
199			.I -fc
200			is specified, the output will be a Radiance spectral picture.
201	greg	1.1	.PP
202			The
203			.I \-v
204			option turns on verbose reporting, which announces each operation.
205			.SH EXAMPLES
206			To concatenate two matrix files with a BTDF between them and write
207			the result as binary double:
208			.IP "" .2i
209			rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
210			.PP
211			To convert a BTDF matrix into a Radiance picture:
212			.IP "" .2i
213			rmtxop -fc blinds.xml > blinds.hdr
214			.PP
215	greg	1.16	To extract the luminance values from a picture as an ASCII matrix:
216			.IP "" .2i
217			rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
218			.PP
219	greg	1.25	To render a melanopic illuminance image with
220			.I rtrace\:
221			.IP "" .2i
222			vwrays -ff -x 1024 -y 1024 -vf myview.vf \|
223			rtrace -fff -cs 18 -co+ -i+ `vwrays -x 1024 -y 1024 -vf myview.vf -d` scene.oct \|
224			rmtxop -fc -c M - > scene_meli.hdr
225			.PP
226	greg	1.1	To scale a matrix by 4 and add it to the transpose of another matrix:
227			.IP "" .2i
228	greg	1.16	rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
229			.PP
230			To multiply elements of two matrices, then concatenate with a third,
231			applying a final transpose to the result:
232			.IP "" .2i
233			rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
234	greg	1.1	.PP
235	greg	1.15	To left-multiply the element-wise division of two matrices:
236			.IP "" .2i
237			rmtxop -fd numerator.mtx / denominator.mtx \| rmtxop left.mtx - > result.mtx
238			.PP
239	greg	1.1	To send the elements of a binary matrix to
240			.I rcalc(1)
241			for further processing:
242			.IP "" .2i
243	greg	1.5	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
244	greg	1.13	.SH NOTES
245	greg	1.16	Matrix concatenation is associative but not commutative, so order
246	greg	1.13	matters to the result.
247			.I Rmtxop
248	greg	1.16	takes advantage of this associative property to concatenate
249			from right to left when it reduces the number of basic operations.
250	greg	1.13	If the rightmost matrix is a column vector for example, it is
251	greg	1.16	much faster to concatenate from the right, and the result will
252	greg	1.13	be the same.
253	greg	1.16	Note that this only applies to concatenation;
254			element-wise addition, multiplication, and division are always
255	greg	1.13	evaluated from left to right.
256	greg	1.1	.SH AUTHOR
257			Greg Ward
258			.SH "SEE ALSO"
259	greg	1.25	cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1),
260			ra_xyze(1), rcalc(1),
261	greg	1.23	rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), rlam(1),
262	greg	1.25	rsplit(1), rtrace(1), tabfunc(1), total(1), vwrays(1),
263			wrapBSDF(1)