man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.20 2021/01/19 23:32:00 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 -r[fb]
]
.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:	1.21
Committed:	Thu Jan 21 17:30:20 2021 UTC (4 years, 3 months ago) by greg
Branch:	MAIN
Changes since 1.20:	+2 -2 lines
Log Message:	docs: typo
#	Content
1	.\" RCSid "$Id: rmtxop.1,v 1.20 2021/01/19 23:32:00 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 -r[fb]
19	]
20	.B m1
21	[
22	.B ".+*/"
23	]
24	.B ".."
25	.SH DESCRIPTION
26	.I Rmtxop
27	loads and concatenates or adds/multiplies/divides
28	together component matrix files given on the command line.
29	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	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	Two special cases are handled for component matrices that are either
52	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	(XML files cannot be read from the standard input or from a command.)\0
61	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	is at the top with the first column on the left.
66	Any exposure changes that were applied to the pictures before
67	.I rmtxop
68	will be undone, similar to the
69	.I pcomb(1)
70	.I \-o
71	option.
72	.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	line are concatenated together, unless separated by a plus ('+'),
113	asterisk ('*'), or forward slash ('/') symbol,
114	in which case the individual matrix elements are added,
115	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	In the case of addition, the two matrices involved must have the same number
119	of components.
120	If subtraction is desired, use addition ('+') with a scaling parameter of -1
121	for the second matrix (the
122	.I \-s
123	option).
124	For element-wise multiplication and division, the second matrix is
125	permitted to have a single component per element, which will be
126	applied equally to all components of the first matrix.
127	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	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	The number of components in the next matrix after applying any
138	.I -c
139	transform must agree with the prior result.
140	For concatenation (matrix multiplication), the number of columns
141	in the prior result must equal the number of rows in the next matrix, and
142	the result will have the number of rows of the previous and the number
143	of columns of the next matrix.
144	In the case of addition, multiplication, and division,
145	the number of rows and columns of the prior result and the
146	next matrix must match, and will not be changed by the operation.
147	.PP
148	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	Results are sent to the standard output.
158	By default, the values will be written in the lowest resolution format
159	among the inputs, but the
160	.I \-f
161	option may be used to explicitly output components
162	as ASCII (-fa), binary doubles (-fd), floats (-ff), or RGBE colors (-fc).
163	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	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	To scale a matrix by 4 and add it to the transpose of another matrix:
187	.IP "" .2i
188	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	.PP
195	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	To send the elements of a binary matrix to
200	.I rcalc(1)
201	for further processing:
202	.IP "" .2i
203	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
204	.SH NOTES
205	Matrix concatenation is associative but not commutative, so order
206	matters to the result.
207	.I Rmtxop
208	takes advantage of this associative property to concatenate
209	from right to left when it reduces the number of basic operations.
210	If the rightmost matrix is a column vector for example, it is
211	much faster to concatenate from the right, and the result will
212	be the same.
213	Note that this only applies to concatenation;
214	element-wise addition, multiplication, and division are always
215	evaluated from left to right.
216	.SH AUTHOR
217	Greg Ward
218	.SH "SEE ALSO"
219	cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1), rcalc(1),
220	rcollate(1), rcontrib(1), rfluxmtx(1), rlam(1),
221	rsplit(1), tabfunc(1), total(1), wrapBSDF(1)