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, 8 months ago) by greg
Branch:	MAIN
Changes since 1.15:	+27 -12 lines
Log Message:	Further clarifications and examples
#	Content
1	.\" RCSid "$Id: rmtxop.1,v 1.15 2019/08/12 16:55:24 greg Exp $"
2	.TH RMTXOP 1 7/8/97 RADIANCE
3	.SH NAME
4	rmtxop - concatenate, add, multiply, divide, transpose, scale, and convert matrices
5	.SH SYNOPSIS
6	.B rmtxop
7	[
8	.B \-v
9	][
10	.B \-f[afdc]
11	][
12	.B \-t
13	][
14	.B "\-s sf .."
15	][
16	.B "\-c ce .."
17	]
18	.B m1
19	[
20	.B ".+*/"
21	]
22	.B ".."
23	.SH DESCRIPTION
24	.I Rmtxop
25	loads and concatenates or adds/multiplies/divides
26	together component matrix files given on the command line.
27	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	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	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	(XML files cannot be read from the standard input or from a command.)\0
54	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	is at the top with the first column on the left.
59	.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	line are concatenated together, unless separated by a plus ('+'),
100	asterisk ('*'), or forward slash ('/') symbol,
101	in which case the individual matrix elements are added,
102	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	In the case of addition, the two matrices involved must have the same number
106	of components.
107	If subtraction is desired, use addition ('+') with a scaling parameter of -1
108	for the second matrix (the
109	.I \-s
110	option).
111	For element-wise multiplication and division, the second matrix is
112	permitted to have a single component per element, which will be
113	applied equally to all components of the first matrix.
114	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	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	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	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	.PP
135	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	Results are sent to the standard output.
145	By default, the values will be written in the lowest resolution format
146	among the inputs, but the
147	.I \-f
148	option may be used to explicitly output components
149	as ASCII (-fa), binary doubles (-fd), floats (-ff), or RGBE colors (-fc).
150	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	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	To scale a matrix by 4 and add it to the transpose of another matrix:
174	.IP "" .2i
175	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	.PP
182	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	To send the elements of a binary matrix to
187	.I rcalc(1)
188	for further processing:
189	.IP "" .2i
190	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
191	.SH NOTES
192	Matrix concatenation is associative but not commutative, so order
193	matters to the result.
194	.I Rmtxop
195	takes advantage of this associative property to concatenate
196	from right to left when it reduces the number of basic operations.
197	If the rightmost matrix is a column vector for example, it is
198	much faster to concatenate from the right, and the result will
199	be the same.
200	Note that this only applies to concatenation;
201	element-wise addition, multiplication, and division are always
202	evaluated from left to right.
203	.SH AUTHOR
204	Greg Ward
205	.SH "SEE ALSO"
206	cnt(1), getinfo(1), histo(1), neaten(1), rcalc(1), rcollate(1),
207	rcontrib(1), rfluxmtx(1), rlam(1),
208	rsplit(1), tabfunc(1), total(1), wrapBSDF(1)