man/man1/rmtxop.1

.\" RCSid "$Id: rmtxop.1,v 1.27 2023/12/02 00:42:21 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 "\-C {symbols|file}"
][
.B "\-c ce .."
][
.B "\-s sf .."
][
.B \-t
][
.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 metadata:
.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}
.fi
.sp
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.
Similarly, any of the 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 input, the
.I \-t
and
.I \-c
and/or
.I \-s
options may be used to modify the matrix.
The
.I \-t
option transposes the matrix, swapping rows and columns.
The
.I \-c
option can "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.
.PP
Alternatively, a set of symbolic output components may be given to the
.I \-c
option, with the following definitions:
.sp
.nf
R       - red channel
G       - green channel
B       - blue channel
X       - CIE X channel
Y       - CIE Y channel (aka., luminance or illuminance)
Z       - CIE Z channel
S       - scotopic luminance or illuminance
M       - melanopic luminance or illuminance
A       - average component value
.fi
.sp
These letters may be given in any order as a single string, and if
.I "-c RGB"
or
.I "-c XYZ"
is specified for an input picture or the
.I "-fc"
option is given, the output will be written as a RGBE or XYZE picture.
Note that conversion from a float or RGBE color space applies a conversion
of 179 lumens/watt (for CIE or melanopic output) or 412 (for scotopic output),
and the reverse happens for conversion from XYZE input to RGB or RGBE output.
.PP
If a matrix or picture file path is given to the
.I \-c
option, then the color space of that file will be used, instead.
.PP
The
.I \-C
option takes either a symbolic color space or an input file, and will be
applied to all subsequent matrices that do not have their own associated
.I \-c
option.
.PP
Additionally, 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
.I after
application of any
.I \-c
option for this input matrix or picture, even if the
.I \-s
option appears first.
.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 transform/scaling operation may be applied to
the results by appending the
.I \-t
and
.I \-c
and/or
.I \-s
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 precision format
among the inputs, but the
.I \-f[adfc]
option may be used to explicitly output components
as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent
colors/spectra (-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 render a melanopic illuminance image with
.I rtrace\:
.IP "" .2i
vwrays -ff -x 1024 -y 1024 -vf myview.vf |
rtrace -fff -cs 18 -co+ -i+ `vwrays -x 1024 -y 1024 -vf myview.vf -d` scene.oct |
rmtxop -fc -c M - > scene_meli.hdr
.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), dctimestep(1), getinfo(1), pcomb(1), ra_xyze(1), rcalc(1),
rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1),
rmtxcomb(1), rtrace(1), vwrays(1), wrapBSDF(1)
Revision:	1.28
Committed:	Wed Dec 6 01:27:00 2023 UTC (23 months ago) by greg
Branch:	MAIN
Changes since 1.27:	+17 -18 lines
Log Message:	docs(rmtxcomb): Added man page for new rmtxcomb tool
#	User	Rev	Content
1	greg	1.28	.\" RCSid "$Id: rmtxop.1,v 1.27 2023/12/02 00:42:21 greg Exp $"
2	greg	1.23	.TH RMTXOP 1 5/31/2014 RADIANCE
3	greg	1.1	.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	greg	1.27	.B "\-C {symbols\|file}"
13	greg	1.1	][
14	greg	1.25	.B "\-c ce .."
15			][
16	greg	1.1	.B "\-s sf .."
17			][
18	greg	1.27	.B \-t
19			][
20	greg	1.22	.B "\-rf\|\-rb"
21	greg	1.1	]
22			.B m1
23			[
24	greg	1.13	.B ".+*/"
25	greg	1.1	]
26			.B ".."
27			.SH DESCRIPTION
28			.I Rmtxop
29	greg	1.10	loads and concatenates or adds/multiplies/divides
30			together component matrix files given on the command line.
31	greg	1.28	Each file must have a header containing the following metadata:
32	greg	1.1	.sp
33			.nf
34			NROWS={number of rows}
35			NCOLS={number of columns}
36			NCOMP={number of components}
37	greg	1.24	FORMAT={ascii\|float\|double\|32-bit_rle_rgbe\|32-bit_rle_xyze\|Radiance_spectra}
38	greg	1.25	.fi
39	greg	1.1	.sp
40			The number of components indicates that each matrix element is actually
41			composed of multiple elements, most commonly an RGB triple.
42			This is essentially dividing the matrix into planes, where each component
43			participates in a separate calculation.
44			If an appropriate header is not present, it may be added with a call to
45			.I rcollate(1).
46			A matrix may be read from the standard input using a hyphen by itself ('-')
47			in the appropriate place on the command line.
48	greg	1.28	Similarly, any of the inputs may be read from a command
49	greg	1.9	instead of a file by
50			using quotes and a beginning exclamation point ('!').
51			.PP
52	greg	1.1	Two special cases are handled for component matrices that are either
53	greg	1.20	XML files containing BSDF data, or Radiance picture files.
54			In the first case, the BSDF library loads and interprets the
55			transmission matrix by default.
56			Alternatively, the front (normal-side) reflectance is selected if the
57			.I \-rf
58			option precedes the file name, or the backside reflectance if
59			.I \-rb
60			is specified.
61	greg	1.9	(XML files cannot be read from the standard input or from a command.)\0
62	greg	1.1	In the second case, the RGBE or XYZE values are loaded in a 3-component
63			matrix where the number of columns match the X-dimension of the picture, and
64			the number of rows match the Y-dimension.
65			The picture must be in standard pixel ordering, and the first row
66	greg	1.7	is at the top with the first column on the left.
67	greg	1.21	Any exposure changes that were applied to the pictures before
68	greg	1.18	.I rmtxop
69			will be undone, similar to the
70	greg	1.19	.I pcomb(1)
71	greg	1.18	.I \-o
72			option.
73	greg	1.24	Radiance spectral pictures with more than 3 components are also supported.
74			These are typically produced by
75			.I rtrace(1)
76			or
77			.I rfluxmtx(1).
78	greg	1.1	.PP
79	greg	1.28	Before each input, the
80	greg	1.1	.I \-t
81			and
82	greg	1.25	.I \-c
83			and/or
84	greg	1.1	.I \-s
85			options may be used to modify the matrix.
86			The
87			.I \-t
88			option transposes the matrix, swapping rows and columns.
89			The
90			.I \-c
91	greg	1.25	option can "transform" the element values, possibly changing
92	greg	1.1	the number of components in the matrix.
93			For example, a 3-component matrix can be transformed into a single-component
94			matrix by using
95			.I \-c
96			with three coefficients.
97			A four-component matrix can be turned into a two-component matrix using 8
98			coefficients, where the first four coefficients will be used to compute
99			the first new component, and the second four coefficients
100			yield the second new component.
101			Note that the number of coefficients must be an even multiple of the number
102			of original components.
103	greg	1.27	.PP
104			Alternatively, a set of symbolic output components may be given to the
105			.I \-c
106			option, with the following definitions:
107	greg	1.25	.sp
108			.nf
109			R - red channel
110			G - green channel
111			B - blue channel
112			X - CIE X channel
113			Y - CIE Y channel (aka., luminance or illuminance)
114			Z - CIE Z channel
115			S - scotopic luminance or illuminance
116			M - melanopic luminance or illuminance
117	greg	1.26	A - average component value
118	greg	1.25	.fi
119			.sp
120			These letters may be given in any order as a single string, and if
121			.I "-c RGB"
122			or
123			.I "-c XYZ"
124	greg	1.28	is specified for an input picture or the
125	greg	1.25	.I "-fc"
126	greg	1.28	option is given, the output will be written as a RGBE or XYZE picture.
127	greg	1.25	Note that conversion from a float or RGBE color space applies a conversion
128			of 179 lumens/watt (for CIE or melanopic output) or 412 (for scotopic output),
129			and the reverse happens for conversion from XYZE input to RGB or RGBE output.
130			.PP
131	greg	1.28	If a matrix or picture file path is given to the
132	greg	1.27	.I \-c
133			option, then the color space of that file will be used, instead.
134			.PP
135			The
136			.I \-C
137			option takes either a symbolic color space or an input file, and will be
138			applied to all subsequent matrices that do not have their own associated
139			.I \-c
140			option.
141			.PP
142	greg	1.25	Additionally, the
143	greg	1.1	.I \-s
144	greg	1.25	option applies the given scalar factor(s) to the elements of the matrix.
145			If only one factor is provided,
146			it will be used for all components.
147			If multiple factors are given, their number must match the number of matrix
148			components
149			.I after
150			application of any
151	greg	1.1	.I \-c
152	greg	1.28	option for this input matrix or picture, even if the
153			.I \-s
154			option appears first.
155	greg	1.1	.PP
156			If present, the second and subsequent matrices on the command
157	greg	1.16	line are concatenated together, unless separated by a plus ('+'),
158	greg	1.10	asterisk ('*'), or forward slash ('/') symbol,
159	greg	1.15	in which case the individual matrix elements are added,
160	greg	1.16	multiplied, or divided, respectively.
161			The concatenation operator ('.') is the default and need not be specified.
162			Note also that the asterisk must be quoted or escaped in most shells.
163	greg	1.10	In the case of addition, the two matrices involved must have the same number
164			of components.
165	greg	1.15	If subtraction is desired, use addition ('+') with a scaling parameter of -1
166			for the second matrix (the
167			.I \-s
168			option).
169	greg	1.11	For element-wise multiplication and division, the second matrix is
170	greg	1.15	permitted to have a single component per element, which will be
171	greg	1.11	applied equally to all components of the first matrix.
172	greg	1.10	If element-wise division is specified, any zero elements in the second
173			matrix will result in a warning and the corresponding component(s) in the
174			first matrix will be set to zero.
175			.PP
176	greg	1.16	Evaluation proceeds from left to right, and all operations have
177			the same precedence.
178			If a different evaluation order is desired, pipe the result of one
179			.I rmtxop
180			command into another, as shown in one of the examples below.
181			.PP
182	greg	1.17	The number of components in the next matrix after applying any
183	greg	1.1	.I -c
184			transform must agree with the prior result.
185			For concatenation (matrix multiplication), the number of columns
186	greg	1.17	in the prior result must equal the number of rows in the next matrix, and
187	greg	1.1	the result will have the number of rows of the previous and the number
188	greg	1.17	of columns of the next matrix.
189	greg	1.10	In the case of addition, multiplication, and division,
190			the number of rows and columns of the prior result and the
191	greg	1.17	next matrix must match, and will not be changed by the operation.
192	greg	1.1	.PP
193	greg	1.25	A final transpose or transform/scaling operation may be applied to
194	greg	1.14	the results by appending the
195			.I \-t
196			and
197	greg	1.25	.I \-c
198			and/or
199	greg	1.14	.I \-s
200			options after the last matrix on the command line.
201			.PP
202	greg	1.1	Results are sent to the standard output.
203	greg	1.28	By default, the values will be written in the lowest precision format
204	greg	1.6	among the inputs, but the
205	greg	1.28	.I \-f[adfc]
206	greg	1.4	option may be used to explicitly output components
207	greg	1.25	as ASCII (-fa), binary doubles (-fd), floats (-ff), or common-exponent
208			colors/spectra (-fc).
209	greg	1.28	In the latter case, the actual matrix dimensions are written in
210			the resolution string rather than the header.
211	greg	1.24	Also, matrix results will be written as standard
212			Radiance pictures if they have either one
213	greg	1.1	or three components.
214			In the one-component case, the output is written as grayscale.
215	greg	1.24	If more than 3 components are in the final matrix and
216			.I -fc
217			is specified, the output will be a Radiance spectral picture.
218	greg	1.1	.PP
219			The
220			.I \-v
221			option turns on verbose reporting, which announces each operation.
222			.SH EXAMPLES
223			To concatenate two matrix files with a BTDF between them and write
224			the result as binary double:
225			.IP "" .2i
226			rmtxop -fd view.vmx blinds.xml exterior.dmx > dcoef.dmx
227			.PP
228			To convert a BTDF matrix into a Radiance picture:
229			.IP "" .2i
230			rmtxop -fc blinds.xml > blinds.hdr
231			.PP
232	greg	1.16	To extract the luminance values from a picture as an ASCII matrix:
233			.IP "" .2i
234			rmtxop -fa -c .265 .670 .065 image.hdr > image_lum.mtx
235			.PP
236	greg	1.25	To render a melanopic illuminance image with
237			.I rtrace\:
238			.IP "" .2i
239			vwrays -ff -x 1024 -y 1024 -vf myview.vf \|
240			rtrace -fff -cs 18 -co+ -i+ `vwrays -x 1024 -y 1024 -vf myview.vf -d` scene.oct \|
241			rmtxop -fc -c M - > scene_meli.hdr
242			.PP
243	greg	1.1	To scale a matrix by 4 and add it to the transpose of another matrix:
244			.IP "" .2i
245	greg	1.16	rmtxop -s 4 first.mtx + -t second.mtx > result.mtx
246			.PP
247			To multiply elements of two matrices, then concatenate with a third,
248			applying a final transpose to the result:
249			.IP "" .2i
250			rmtxop first.mtx \\* second.mtx . third.mtx -t > result.mtx
251	greg	1.1	.PP
252	greg	1.15	To left-multiply the element-wise division of two matrices:
253			.IP "" .2i
254			rmtxop -fd numerator.mtx / denominator.mtx \| rmtxop left.mtx - > result.mtx
255			.PP
256	greg	1.1	To send the elements of a binary matrix to
257			.I rcalc(1)
258			for further processing:
259			.IP "" .2i
260	greg	1.5	rmtxop -fa orig.mtx \| rcollate -ho -oc 1 \| rcalc [operations]
261	greg	1.13	.SH NOTES
262	greg	1.16	Matrix concatenation is associative but not commutative, so order
263	greg	1.13	matters to the result.
264			.I Rmtxop
265	greg	1.16	takes advantage of this associative property to concatenate
266			from right to left when it reduces the number of basic operations.
267	greg	1.13	If the rightmost matrix is a column vector for example, it is
268	greg	1.16	much faster to concatenate from the right, and the result will
269	greg	1.13	be the same.
270	greg	1.16	Note that this only applies to concatenation;
271			element-wise addition, multiplication, and division are always
272	greg	1.13	evaluated from left to right.
273	greg	1.1	.SH AUTHOR
274			Greg Ward
275			.SH "SEE ALSO"
276	greg	1.28	cnt(1), dctimestep(1), getinfo(1), pcomb(1), ra_xyze(1), rcalc(1),
277			rcollate(1), rcontrib(1), rcrop(1), rfluxmtx(1),
278			rmtxcomb(1), rtrace(1), vwrays(1), wrapBSDF(1)