man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.23 2022/03/15 00:25:50 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 "\-s sf .."
][
.B "\-c ce .."
][
.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}
.sp
.fi
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 \-s
or
.I \-c
options may be used to modify the matrix.
The
.I \-t
option transposes the matrix, swapping rows and columns.
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.
Alternatively, the
.I \-c
option may be used to "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.
The
.I \-s
and
.I \-c
options are mutually exclusive, insofar as they cannot be applied together
to the same input matrix.
.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 scaling/transform operation may be applied to
the results by appending the
.I \-t
and
.I \-s
or
.I \-c
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 (-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 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), rcalc(1),
rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), rlam(1), 
rsplit(1), rtrace(1), tabfunc(1), total(1), wrapBSDF(1)
Revision:	1.24
Committed:	Tue Nov 21 02:16:59 2023 UTC (17 months, 4 weeks ago) by greg
Branch:	MAIN
Changes since 1.23:	+14 -5 lines
Log Message:	docs: Added mention of Radiance spectral picture support
#	User	Rev	Content
1	greg	1.24	.\" RCSid "$Id: rmtxop.1,v 1.23 2022/03/15 00:25:50 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			.B "\-s sf .."
15			][
16			.B "\-c ce .."
17	greg	1.20	][
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	1.1	.sp
37			.fi
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			.I \-s
82			or
83			.I \-c
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 \-s
90			option applies the given scalar factor(s) to the elements of the matrix.
91			If only one factor is provided,
92			it will be used for all components.
93			If multiple factors are given, their number must match the number of matrix
94			components.
95			Alternatively, the
96			.I \-c
97			option may be used to "transform" the element values, possibly changing
98			the number of components in the matrix.
99			For example, a 3-component matrix can be transformed into a single-component
100			matrix by using
101			.I \-c
102			with three coefficients.
103			A four-component matrix can be turned into a two-component matrix using 8
104			coefficients, where the first four coefficients will be used to compute
105			the first new component, and the second four coefficients
106			yield the second new component.
107			Note that the number of coefficients must be an even multiple of the number
108			of original components.
109			The
110			.I \-s
111			and
112			.I \-c
113			options are mutually exclusive, insofar as they cannot be applied together
114			to the same input matrix.
115			.PP
116			If present, the second and subsequent matrices on the command
117	greg	1.16	line are concatenated together, unless separated by a plus ('+'),
118	greg	1.10	asterisk ('*'), or forward slash ('/') symbol,
119	greg	1.15	in which case the individual matrix elements are added,
120	greg	1.16	multiplied, or divided, respectively.
121			The concatenation operator ('.') is the default and need not be specified.
122			Note also that the asterisk must be quoted or escaped in most shells.
123	greg	1.10	In the case of addition, the two matrices involved must have the same number
124			of components.
125	greg	1.15	If subtraction is desired, use addition ('+') with a scaling parameter of -1
126			for the second matrix (the
127			.I \-s
128			option).
129	greg	1.11	For element-wise multiplication and division, the second matrix is
130	greg	1.15	permitted to have a single component per element, which will be
131	greg	1.11	applied equally to all components of the first matrix.
132	greg	1.10	If element-wise division is specified, any zero elements in the second
133			matrix will result in a warning and the corresponding component(s) in the
134			first matrix will be set to zero.
135			.PP
136	greg	1.16	Evaluation proceeds from left to right, and all operations have
137			the same precedence.
138			If a different evaluation order is desired, pipe the result of one
139			.I rmtxop
140			command into another, as shown in one of the examples below.
141			.PP
142	greg	1.17	The number of components in the next matrix after applying any
143	greg	1.1	.I -c
144			transform must agree with the prior result.
145			For concatenation (matrix multiplication), the number of columns
146	greg	1.17	in the prior result must equal the number of rows in the next matrix, and
147	greg	1.1	the result will have the number of rows of the previous and the number
148	greg	1.17	of columns of the next matrix.
149	greg	1.10	In the case of addition, multiplication, and division,
150			the number of rows and columns of the prior result and the
151	greg	1.17	next matrix must match, and will not be changed by the operation.
152	greg	1.1	.PP
153	greg	1.14	A final transpose or scaling/transform operation may be applied to
154			the results by appending the
155			.I \-t
156			and
157			.I \-s
158			or
159			.I \-c
160			options after the last matrix on the command line.
161			.PP
162	greg	1.1	Results are sent to the standard output.
163	greg	1.4	By default, the values will be written in the lowest resolution format
164	greg	1.6	among the inputs, but the
165	greg	1.1	.I \-f
166	greg	1.4	option may be used to explicitly output components
167	greg	1.24	as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent colors (-fc).
168	greg	1.1	In the latter case, the actual matrix dimensions are written in the resolution
169			string rather than the header.
170	greg	1.24	Also, matrix results will be written as standard
171			Radiance pictures if they have either one
172	greg	1.1	or three components.
173			In the one-component case, the output is written as grayscale.
174	greg	1.24	If more than 3 components are in the final matrix and
175			.I -fc
176			is specified, the output will be a Radiance spectral picture.
177	greg	1.1	.PP
178			The
179			.I \-v
180			option turns on verbose reporting, which announces each operation.
181			.SH EXAMPLES
182			To concatenate two matrix files with a BTDF between them and write
183			the result as binary double:
184			.IP "" .2i
185			rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
186			.PP
187			To convert a BTDF matrix into a Radiance picture:
188			.IP "" .2i
189			rmtxop -fc blinds.xml > blinds.hdr
190			.PP
191	greg	1.16	To extract the luminance values from a picture as an ASCII matrix:
192			.IP "" .2i
193			rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
194			.PP
195	greg	1.1	To scale a matrix by 4 and add it to the transpose of another matrix:
196			.IP "" .2i
197	greg	1.16	rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
198			.PP
199			To multiply elements of two matrices, then concatenate with a third,
200			applying a final transpose to the result:
201			.IP "" .2i
202			rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
203	greg	1.1	.PP
204	greg	1.15	To left-multiply the element-wise division of two matrices:
205			.IP "" .2i
206			rmtxop -fd numerator.mtx / denominator.mtx \| rmtxop left.mtx - > result.mtx
207			.PP
208	greg	1.1	To send the elements of a binary matrix to
209			.I rcalc(1)
210			for further processing:
211			.IP "" .2i
212	greg	1.5	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
213	greg	1.13	.SH NOTES
214	greg	1.16	Matrix concatenation is associative but not commutative, so order
215	greg	1.13	matters to the result.
216			.I Rmtxop
217	greg	1.16	takes advantage of this associative property to concatenate
218			from right to left when it reduces the number of basic operations.
219	greg	1.13	If the rightmost matrix is a column vector for example, it is
220	greg	1.16	much faster to concatenate from the right, and the result will
221	greg	1.13	be the same.
222	greg	1.16	Note that this only applies to concatenation;
223			element-wise addition, multiplication, and division are always
224	greg	1.13	evaluated from left to right.
225	greg	1.1	.SH AUTHOR
226			Greg Ward
227			.SH "SEE ALSO"
228	greg	1.18	cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1), rcalc(1),
229	greg	1.23	rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), rlam(1),
230	greg	1.24	rsplit(1), rtrace(1), tabfunc(1), total(1), wrapBSDF(1)