man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.25 2023/11/27 22:04:45 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
A       - average component value
.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:	1.26
Committed:	Wed Nov 29 18:56:28 2023 UTC (17 months, 2 weeks ago) by greg
Branch:	MAIN
Changes since 1.25:	+2 -1 lines
Log Message:	feat(rmtxop): Added 'A' symbolic component for average of all channels
#	User	Rev	Content
1	greg	1.26	.\" RCSid "$Id: rmtxop.1,v 1.25 2023/11/27 22:04:45 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	greg	1.26	A - average component value
115	greg	1.25	.fi
116			.sp
117			These letters may be given in any order as a single string, and if
118			.I "-c RGB"
119			or
120			.I "-c XYZ"
121			is specified along with a
122			.I "-fc"
123			option, the output will be written as a RGBE or XYZE picture, respectively.
124			Note that conversion from a float or RGBE color space applies a conversion
125			of 179 lumens/watt (for CIE or melanopic output) or 412 (for scotopic output),
126			and the reverse happens for conversion from XYZE input to RGB or RGBE output.
127			.PP
128			Additionally, the
129	greg	1.1	.I \-s
130	greg	1.25	option applies the given scalar factor(s) to the elements of the matrix.
131			If only one factor is provided,
132			it will be used for all components.
133			If multiple factors are given, their number must match the number of matrix
134			components
135			.I after
136			application of any
137	greg	1.1	.I \-c
138	greg	1.25	option for this input matrix or picture.
139	greg	1.1	.PP
140			If present, the second and subsequent matrices on the command
141	greg	1.16	line are concatenated together, unless separated by a plus ('+'),
142	greg	1.10	asterisk ('*'), or forward slash ('/') symbol,
143	greg	1.15	in which case the individual matrix elements are added,
144	greg	1.16	multiplied, or divided, respectively.
145			The concatenation operator ('.') is the default and need not be specified.
146			Note also that the asterisk must be quoted or escaped in most shells.
147	greg	1.10	In the case of addition, the two matrices involved must have the same number
148			of components.
149	greg	1.15	If subtraction is desired, use addition ('+') with a scaling parameter of -1
150			for the second matrix (the
151			.I \-s
152			option).
153	greg	1.11	For element-wise multiplication and division, the second matrix is
154	greg	1.15	permitted to have a single component per element, which will be
155	greg	1.11	applied equally to all components of the first matrix.
156	greg	1.10	If element-wise division is specified, any zero elements in the second
157			matrix will result in a warning and the corresponding component(s) in the
158			first matrix will be set to zero.
159			.PP
160	greg	1.16	Evaluation proceeds from left to right, and all operations have
161			the same precedence.
162			If a different evaluation order is desired, pipe the result of one
163			.I rmtxop
164			command into another, as shown in one of the examples below.
165			.PP
166	greg	1.17	The number of components in the next matrix after applying any
167	greg	1.1	.I -c
168			transform must agree with the prior result.
169			For concatenation (matrix multiplication), the number of columns
170	greg	1.17	in the prior result must equal the number of rows in the next matrix, and
171	greg	1.1	the result will have the number of rows of the previous and the number
172	greg	1.17	of columns of the next matrix.
173	greg	1.10	In the case of addition, multiplication, and division,
174			the number of rows and columns of the prior result and the
175	greg	1.17	next matrix must match, and will not be changed by the operation.
176	greg	1.1	.PP
177	greg	1.25	A final transpose or transform/scaling operation may be applied to
178	greg	1.14	the results by appending the
179			.I \-t
180			and
181	greg	1.25	.I \-c
182			and/or
183	greg	1.14	.I \-s
184			options after the last matrix on the command line.
185			.PP
186	greg	1.1	Results are sent to the standard output.
187	greg	1.4	By default, the values will be written in the lowest resolution format
188	greg	1.6	among the inputs, but the
189	greg	1.1	.I \-f
190	greg	1.4	option may be used to explicitly output components
191	greg	1.25	as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent
192			colors/spectra (-fc).
193	greg	1.1	In the latter case, the actual matrix dimensions are written in the resolution
194			string rather than the header.
195	greg	1.24	Also, matrix results will be written as standard
196			Radiance pictures if they have either one
197	greg	1.1	or three components.
198			In the one-component case, the output is written as grayscale.
199	greg	1.24	If more than 3 components are in the final matrix and
200			.I -fc
201			is specified, the output will be a Radiance spectral picture.
202	greg	1.1	.PP
203			The
204			.I \-v
205			option turns on verbose reporting, which announces each operation.
206			.SH EXAMPLES
207			To concatenate two matrix files with a BTDF between them and write
208			the result as binary double:
209			.IP "" .2i
210			rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
211			.PP
212			To convert a BTDF matrix into a Radiance picture:
213			.IP "" .2i
214			rmtxop -fc blinds.xml > blinds.hdr
215			.PP
216	greg	1.16	To extract the luminance values from a picture as an ASCII matrix:
217			.IP "" .2i
218			rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
219			.PP
220	greg	1.25	To render a melanopic illuminance image with
221			.I rtrace\:
222			.IP "" .2i
223			vwrays -ff -x 1024 -y 1024 -vf myview.vf \|
224			rtrace -fff -cs 18 -co+ -i+ `vwrays -x 1024 -y 1024 -vf myview.vf -d` scene.oct \|
225			rmtxop -fc -c M - > scene_meli.hdr
226			.PP
227	greg	1.1	To scale a matrix by 4 and add it to the transpose of another matrix:
228			.IP "" .2i
229	greg	1.16	rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
230			.PP
231			To multiply elements of two matrices, then concatenate with a third,
232			applying a final transpose to the result:
233			.IP "" .2i
234			rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
235	greg	1.1	.PP
236	greg	1.15	To left-multiply the element-wise division of two matrices:
237			.IP "" .2i
238			rmtxop -fd numerator.mtx / denominator.mtx \| rmtxop left.mtx - > result.mtx
239			.PP
240	greg	1.1	To send the elements of a binary matrix to
241			.I rcalc(1)
242			for further processing:
243			.IP "" .2i
244	greg	1.5	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
245	greg	1.13	.SH NOTES
246	greg	1.16	Matrix concatenation is associative but not commutative, so order
247	greg	1.13	matters to the result.
248			.I Rmtxop
249	greg	1.16	takes advantage of this associative property to concatenate
250			from right to left when it reduces the number of basic operations.
251	greg	1.13	If the rightmost matrix is a column vector for example, it is
252	greg	1.16	much faster to concatenate from the right, and the result will
253	greg	1.13	be the same.
254	greg	1.16	Note that this only applies to concatenation;
255			element-wise addition, multiplication, and division are always
256	greg	1.13	evaluated from left to right.
257	greg	1.1	.SH AUTHOR
258			Greg Ward
259			.SH "SEE ALSO"
260	greg	1.25	cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1),
261			ra_xyze(1), rcalc(1),
262	greg	1.23	rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), rlam(1),
263	greg	1.25	rsplit(1), rtrace(1), tabfunc(1), total(1), vwrays(1),
264			wrapBSDF(1)