man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.15 2019/08/12 16:55:24 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 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 BTDF data, or Radiance picture files.
In the first case, a BSDF library is used to load and interpret the
transmission matrix.
(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.
.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 new 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 new matrix, and
the result will have the number of rows of the previous and the number
of columns of the new matrix.
In the case of addition, multiplication, and division,
the number of rows and columns of the prior result and the
new 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), rcalc(1), rcollate(1),
rcontrib(1), rfluxmtx(1), rlam(1), 
rsplit(1), tabfunc(1), total(1), wrapBSDF(1)
Revision:	1.16
Committed:	Mon Aug 12 17:14:40 2019 UTC (5 years, 9 months ago) by greg
Branch:	MAIN
Changes since 1.15:	+27 -12 lines
Log Message:	Further clarifications and examples
#	User	Rev	Content
1	greg	1.16	.\" RCSid "$Id: rmtxop.1,v 1.15 2019/08/12 16:55:24 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			]
18			.B m1
19			[
20	greg	1.13	.B ".+*/"
21	greg	1.1	]
22			.B ".."
23			.SH DESCRIPTION
24			.I Rmtxop
25	greg	1.10	loads and concatenates or adds/multiplies/divides
26			together component matrix files given on the command line.
27	greg	1.1	Each file must have a header containing the following variables:
28			.sp
29			.nf
30			NROWS={number of rows}
31			NCOLS={number of columns}
32			NCOMP={number of components}
33			FORMAT={ascii\|float\|double\|32-bit_rle_rgbe\|32-bit_rle_xyze}
34			.sp
35			.fi
36			The number of components indicates that each matrix element is actually
37			composed of multiple elements, most commonly an RGB triple.
38			This is essentially dividing the matrix into planes, where each component
39			participates in a separate calculation.
40			If an appropriate header is not present, it may be added with a call to
41			.I rcollate(1).
42			A matrix may be read from the standard input using a hyphen by itself ('-')
43			in the appropriate place on the command line.
44			.PP
45	greg	1.9	Any of the matrix inputs may be read from a command
46			instead of a file by
47			using quotes and a beginning exclamation point ('!').
48			.PP
49	greg	1.1	Two special cases are handled for component matrices that are either
50			XML files containing BTDF data, or Radiance picture files.
51			In the first case, a BSDF library is used to load and interpret the
52			transmission matrix.
53	greg	1.9	(XML files cannot be read from the standard input or from a command.)\0
54	greg	1.1	In the second case, the RGBE or XYZE values are loaded in a 3-component
55			matrix where the number of columns match the X-dimension of the picture, and
56			the number of rows match the Y-dimension.
57			The picture must be in standard pixel ordering, and the first row
58	greg	1.7	is at the top with the first column on the left.
59	greg	1.1	.PP
60			Before each file, the
61			.I \-t
62			and
63			.I \-s
64			or
65			.I \-c
66			options may be used to modify the matrix.
67			The
68			.I \-t
69			option transposes the matrix, swapping rows and columns.
70			The
71			.I \-s
72			option applies the given scalar factor(s) to the elements of the matrix.
73			If only one factor is provided,
74			it will be used for all components.
75			If multiple factors are given, their number must match the number of matrix
76			components.
77			Alternatively, the
78			.I \-c
79			option may be used to "transform" the element values, possibly changing
80			the number of components in the matrix.
81			For example, a 3-component matrix can be transformed into a single-component
82			matrix by using
83			.I \-c
84			with three coefficients.
85			A four-component matrix can be turned into a two-component matrix using 8
86			coefficients, where the first four coefficients will be used to compute
87			the first new component, and the second four coefficients
88			yield the second new component.
89			Note that the number of coefficients must be an even multiple of the number
90			of original components.
91			The
92			.I \-s
93			and
94			.I \-c
95			options are mutually exclusive, insofar as they cannot be applied together
96			to the same input matrix.
97			.PP
98			If present, the second and subsequent matrices on the command
99	greg	1.16	line are concatenated together, unless separated by a plus ('+'),
100	greg	1.10	asterisk ('*'), or forward slash ('/') symbol,
101	greg	1.15	in which case the individual matrix elements are added,
102	greg	1.16	multiplied, or divided, respectively.
103			The concatenation operator ('.') is the default and need not be specified.
104			Note also that the asterisk must be quoted or escaped in most shells.
105	greg	1.10	In the case of addition, the two matrices involved must have the same number
106			of components.
107	greg	1.15	If subtraction is desired, use addition ('+') with a scaling parameter of -1
108			for the second matrix (the
109			.I \-s
110			option).
111	greg	1.11	For element-wise multiplication and division, the second matrix is
112	greg	1.15	permitted to have a single component per element, which will be
113	greg	1.11	applied equally to all components of the first matrix.
114	greg	1.10	If element-wise division is specified, any zero elements in the second
115			matrix will result in a warning and the corresponding component(s) in the
116			first matrix will be set to zero.
117			.PP
118	greg	1.16	Evaluation proceeds from left to right, and all operations have
119			the same precedence.
120			If a different evaluation order is desired, pipe the result of one
121			.I rmtxop
122			command into another, as shown in one of the examples below.
123			.PP
124	greg	1.1	The number of components in the new matrix after applying any
125			.I -c
126			transform must agree with the prior result.
127			For concatenation (matrix multiplication), the number of columns
128			in the prior result must equal the number of rows in the new matrix, and
129			the result will have the number of rows of the previous and the number
130			of columns of the new matrix.
131	greg	1.10	In the case of addition, multiplication, and division,
132			the number of rows and columns of the prior result and the
133			new matrix must match, and will not be changed by the operation.
134	greg	1.1	.PP
135	greg	1.14	A final transpose or scaling/transform operation may be applied to
136			the results by appending the
137			.I \-t
138			and
139			.I \-s
140			or
141			.I \-c
142			options after the last matrix on the command line.
143			.PP
144	greg	1.1	Results are sent to the standard output.
145	greg	1.4	By default, the values will be written in the lowest resolution format
146	greg	1.6	among the inputs, but the
147	greg	1.1	.I \-f
148	greg	1.4	option may be used to explicitly output components
149			as ASCII (-fa), binary doubles (-fd), floats (-ff), or RGBE colors (-fc).
150	greg	1.1	In the latter case, the actual matrix dimensions are written in the resolution
151			string rather than the header.
152			Also, matrix results written as Radiance pictures must have either one
153			or three components.
154			In the one-component case, the output is written as grayscale.
155			.PP
156			The
157			.I \-v
158			option turns on verbose reporting, which announces each operation.
159			.SH EXAMPLES
160			To concatenate two matrix files with a BTDF between them and write
161			the result as binary double:
162			.IP "" .2i
163			rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
164			.PP
165			To convert a BTDF matrix into a Radiance picture:
166			.IP "" .2i
167			rmtxop -fc blinds.xml > blinds.hdr
168			.PP
169	greg	1.16	To extract the luminance values from a picture as an ASCII matrix:
170			.IP "" .2i
171			rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
172			.PP
173	greg	1.1	To scale a matrix by 4 and add it to the transpose of another matrix:
174			.IP "" .2i
175	greg	1.16	rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
176			.PP
177			To multiply elements of two matrices, then concatenate with a third,
178			applying a final transpose to the result:
179			.IP "" .2i
180			rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
181	greg	1.1	.PP
182	greg	1.15	To left-multiply the element-wise division of two matrices:
183			.IP "" .2i
184			rmtxop -fd numerator.mtx / denominator.mtx \| rmtxop left.mtx - > result.mtx
185			.PP
186	greg	1.1	To send the elements of a binary matrix to
187			.I rcalc(1)
188			for further processing:
189			.IP "" .2i
190	greg	1.5	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
191	greg	1.13	.SH NOTES
192	greg	1.16	Matrix concatenation is associative but not commutative, so order
193	greg	1.13	matters to the result.
194			.I Rmtxop
195	greg	1.16	takes advantage of this associative property to concatenate
196			from right to left when it reduces the number of basic operations.
197	greg	1.13	If the rightmost matrix is a column vector for example, it is
198	greg	1.16	much faster to concatenate from the right, and the result will
199	greg	1.13	be the same.
200	greg	1.16	Note that this only applies to concatenation;
201			element-wise addition, multiplication, and division are always
202	greg	1.13	evaluated from left to right.
203	greg	1.1	.SH AUTHOR
204			Greg Ward
205			.SH "SEE ALSO"
206	greg	1.5	cnt(1), getinfo(1), histo(1), neaten(1), rcalc(1), rcollate(1),
207	greg	1.12	rcontrib(1), rfluxmtx(1), rlam(1),
208			rsplit(1), tabfunc(1), total(1), wrapBSDF(1)