man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.21 2021/01/21 17:30:20 greg Exp $"
.TH RMTXOP 1 7/8/97 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}
.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.
.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 RGBE colors (-fc).
In the latter case, the actual matrix dimensions are written in the resolution
string rather than the header.
Also, matrix results written as Radiance pictures must have either one
or three components.
In the one-component case, the output is written as grayscale.
.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), rfluxmtx(1), rlam(1), 
rsplit(1), tabfunc(1), total(1), wrapBSDF(1)
Revision:	1.22
Committed:	Thu Jan 21 17:47:07 2021 UTC (4 years, 9 months ago) by greg
Branch:	MAIN
Changes since 1.21:	+2 -2 lines
Log Message:	docs: formatting of option reminder
#	User	Rev	Content
1	greg	1.22	.\" RCSid "$Id: rmtxop.1,v 1.21 2021/01/21 17:30:20 greg Exp $"
2	greg	1.1	.TH RMTXOP 1 7/8/97 RADIANCE
3			.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			FORMAT={ascii\|float\|double\|32-bit_rle_rgbe\|32-bit_rle_xyze}
36			.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	1.1	.PP
73			Before each file, the
74			.I \-t
75			and
76			.I \-s
77			or
78			.I \-c
79			options may be used to modify the matrix.
80			The
81			.I \-t
82			option transposes the matrix, swapping rows and columns.
83			The
84			.I \-s
85			option applies the given scalar factor(s) to the elements of the matrix.
86			If only one factor is provided,
87			it will be used for all components.
88			If multiple factors are given, their number must match the number of matrix
89			components.
90			Alternatively, the
91			.I \-c
92			option may be used to "transform" the element values, possibly changing
93			the number of components in the matrix.
94			For example, a 3-component matrix can be transformed into a single-component
95			matrix by using
96			.I \-c
97			with three coefficients.
98			A four-component matrix can be turned into a two-component matrix using 8
99			coefficients, where the first four coefficients will be used to compute
100			the first new component, and the second four coefficients
101			yield the second new component.
102			Note that the number of coefficients must be an even multiple of the number
103			of original components.
104			The
105			.I \-s
106			and
107			.I \-c
108			options are mutually exclusive, insofar as they cannot be applied together
109			to the same input matrix.
110			.PP
111			If present, the second and subsequent matrices on the command
112	greg	1.16	line are concatenated together, unless separated by a plus ('+'),
113	greg	1.10	asterisk ('*'), or forward slash ('/') symbol,
114	greg	1.15	in which case the individual matrix elements are added,
115	greg	1.16	multiplied, or divided, respectively.
116			The concatenation operator ('.') is the default and need not be specified.
117			Note also that the asterisk must be quoted or escaped in most shells.
118	greg	1.10	In the case of addition, the two matrices involved must have the same number
119			of components.
120	greg	1.15	If subtraction is desired, use addition ('+') with a scaling parameter of -1
121			for the second matrix (the
122			.I \-s
123			option).
124	greg	1.11	For element-wise multiplication and division, the second matrix is
125	greg	1.15	permitted to have a single component per element, which will be
126	greg	1.11	applied equally to all components of the first matrix.
127	greg	1.10	If element-wise division is specified, any zero elements in the second
128			matrix will result in a warning and the corresponding component(s) in the
129			first matrix will be set to zero.
130			.PP
131	greg	1.16	Evaluation proceeds from left to right, and all operations have
132			the same precedence.
133			If a different evaluation order is desired, pipe the result of one
134			.I rmtxop
135			command into another, as shown in one of the examples below.
136			.PP
137	greg	1.17	The number of components in the next matrix after applying any
138	greg	1.1	.I -c
139			transform must agree with the prior result.
140			For concatenation (matrix multiplication), the number of columns
141	greg	1.17	in the prior result must equal the number of rows in the next matrix, and
142	greg	1.1	the result will have the number of rows of the previous and the number
143	greg	1.17	of columns of the next matrix.
144	greg	1.10	In the case of addition, multiplication, and division,
145			the number of rows and columns of the prior result and the
146	greg	1.17	next matrix must match, and will not be changed by the operation.
147	greg	1.1	.PP
148	greg	1.14	A final transpose or scaling/transform operation may be applied to
149			the results by appending the
150			.I \-t
151			and
152			.I \-s
153			or
154			.I \-c
155			options after the last matrix on the command line.
156			.PP
157	greg	1.1	Results are sent to the standard output.
158	greg	1.4	By default, the values will be written in the lowest resolution format
159	greg	1.6	among the inputs, but the
160	greg	1.1	.I \-f
161	greg	1.4	option may be used to explicitly output components
162			as ASCII (-fa), binary doubles (-fd), floats (-ff), or RGBE colors (-fc).
163	greg	1.1	In the latter case, the actual matrix dimensions are written in the resolution
164			string rather than the header.
165			Also, matrix results written as Radiance pictures must have either one
166			or three components.
167			In the one-component case, the output is written as grayscale.
168			.PP
169			The
170			.I \-v
171			option turns on verbose reporting, which announces each operation.
172			.SH EXAMPLES
173			To concatenate two matrix files with a BTDF between them and write
174			the result as binary double:
175			.IP "" .2i
176			rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
177			.PP
178			To convert a BTDF matrix into a Radiance picture:
179			.IP "" .2i
180			rmtxop -fc blinds.xml > blinds.hdr
181			.PP
182	greg	1.16	To extract the luminance values from a picture as an ASCII matrix:
183			.IP "" .2i
184			rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
185			.PP
186	greg	1.1	To scale a matrix by 4 and add it to the transpose of another matrix:
187			.IP "" .2i
188	greg	1.16	rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
189			.PP
190			To multiply elements of two matrices, then concatenate with a third,
191			applying a final transpose to the result:
192			.IP "" .2i
193			rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
194	greg	1.1	.PP
195	greg	1.15	To left-multiply the element-wise division of two matrices:
196			.IP "" .2i
197			rmtxop -fd numerator.mtx / denominator.mtx \| rmtxop left.mtx - > result.mtx
198			.PP
199	greg	1.1	To send the elements of a binary matrix to
200			.I rcalc(1)
201			for further processing:
202			.IP "" .2i
203	greg	1.5	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
204	greg	1.13	.SH NOTES
205	greg	1.16	Matrix concatenation is associative but not commutative, so order
206	greg	1.13	matters to the result.
207			.I Rmtxop
208	greg	1.16	takes advantage of this associative property to concatenate
209			from right to left when it reduces the number of basic operations.
210	greg	1.13	If the rightmost matrix is a column vector for example, it is
211	greg	1.16	much faster to concatenate from the right, and the result will
212	greg	1.13	be the same.
213	greg	1.16	Note that this only applies to concatenation;
214			element-wise addition, multiplication, and division are always
215	greg	1.13	evaluated from left to right.
216	greg	1.1	.SH AUTHOR
217			Greg Ward
218			.SH "SEE ALSO"
219	greg	1.18	cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1), rcalc(1),
220			rcollate(1), rcontrib(1), rfluxmtx(1), rlam(1),
221	greg	1.12	rsplit(1), tabfunc(1), total(1), wrapBSDF(1)