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, 2 weeks ago) by greg
Branch:	MAIN
Changes since 1.23:	+14 -5 lines
Log Message:	docs: Added mention of Radiance spectral picture support
#	Content
1	.\" RCSid "$Id: rmtxop.1,v 1.23 2022/03/15 00:25:50 greg Exp $"
2	.TH RMTXOP 1 5/31/2014 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 "\-rf\|\-rb"
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\|Radiance_spectra}
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	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	.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	line are concatenated together, unless separated by a plus ('+'),
118	asterisk ('*'), or forward slash ('/') symbol,
119	in which case the individual matrix elements are added,
120	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	In the case of addition, the two matrices involved must have the same number
124	of components.
125	If subtraction is desired, use addition ('+') with a scaling parameter of -1
126	for the second matrix (the
127	.I \-s
128	option).
129	For element-wise multiplication and division, the second matrix is
130	permitted to have a single component per element, which will be
131	applied equally to all components of the first matrix.
132	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	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	The number of components in the next matrix after applying any
143	.I -c
144	transform must agree with the prior result.
145	For concatenation (matrix multiplication), the number of columns
146	in the prior result must equal the number of rows in the next matrix, and
147	the result will have the number of rows of the previous and the number
148	of columns of the next matrix.
149	In the case of addition, multiplication, and division,
150	the number of rows and columns of the prior result and the
151	next matrix must match, and will not be changed by the operation.
152	.PP
153	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	Results are sent to the standard output.
163	By default, the values will be written in the lowest resolution format
164	among the inputs, but the
165	.I \-f
166	option may be used to explicitly output components
167	as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent colors (-fc).
168	In the latter case, the actual matrix dimensions are written in the resolution
169	string rather than the header.
170	Also, matrix results will be written as standard
171	Radiance pictures if they have either one
172	or three components.
173	In the one-component case, the output is written as grayscale.
174	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	.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	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	To scale a matrix by 4 and add it to the transpose of another matrix:
196	.IP "" .2i
197	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	.PP
204	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	To send the elements of a binary matrix to
209	.I rcalc(1)
210	for further processing:
211	.IP "" .2i
212	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
213	.SH NOTES
214	Matrix concatenation is associative but not commutative, so order
215	matters to the result.
216	.I Rmtxop
217	takes advantage of this associative property to concatenate
218	from right to left when it reduces the number of basic operations.
219	If the rightmost matrix is a column vector for example, it is
220	much faster to concatenate from the right, and the result will
221	be the same.
222	Note that this only applies to concatenation;
223	element-wise addition, multiplication, and division are always
224	evaluated from left to right.
225	.SH AUTHOR
226	Greg Ward
227	.SH "SEE ALSO"
228	cnt(1), getinfo(1), histo(1), neaten(1), pcomb(1), rcalc(1),
229	rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1), rlam(1),
230	rsplit(1), rtrace(1), tabfunc(1), total(1), wrapBSDF(1)