man/man1/rcalc.1

.\" RCSid "$Id$"
.TH RCALC 1 4/6/99 RADIANCE
.SH NAME
rcalc - record calculator
.SH SYNOPSIS
.B rcalc
[
.B \-b
][
.B \-l
][
.B \-n
][
.B \-w
][
.B \-u
][
.B \-tS
][
.B "\-i format"
][
.B "\-o format"
][
.B "\-f source"
][
.B "\-e expr"
][
.B "\-s svar=sval"
]
file ..
.SH DESCRIPTION
.I Rcalc
transforms ``records'' from each
.I file
according to the given set of literal and relational information.
By default, records are separated by newlines, and contain
numeric fields separated by tabs.
The
.I \-tS
option is used to specify an alternate tab character.
.PP
A
.I \-i format
option specifies a template for an alternate
input record format.
.I Format
is interpreted as a specification string if it contains a dollar sign '$'.
Otherwise, it is interpreted as the name of the file containing
the format specification.
In either case, if the format does not end with a newline, one will be added
automatically.
A special form of the
.I \-i
option may be followed immediately by a 'd' or an 'f' and an optional
count, which defaults to 1, indicating the number of double or float
binary values to read per record on the input file.
If binary input is specified, no format string or file is needed.
.PP
A
.I \-o format
option specifies an alternate output record format.
It is interpreted the same as an input specification, except that
the special
.I \-od
or
.I \-of
options do not require a count, as this will be determined by the
number of output channels in the given expressions.
.PP
The variable and function definitions in each
.I \-f source
file are read and compiled.
The
.I \-e expr
option can be used to define variables on the command line.
Since many of the characters in an expression have special meaning
to the shell, it should usually be enclosed in single quotes.
The
.I \-s svar=sval
option can be used to assign a string variable a string value.
If this string variable appears in an input format, only records
with the specified value will be processed.
.PP
The
.I \-b
option instructs the program to accept only exact matches.
By default, tabs and spaces are ignored except
as field separators.
The
.I \-l
option instructs the program to ignore newlines in the input,
basically treating them the same as tabs and spaces.
Normally, the beginning of the input format matches the beginning of
a line, and the end of the format matches the end of a line.
With the
.I \-l
option, the input format can match anywhere on a line.
.PP
The
.I \-w
option causes non-fatal error messages (such as division by zero) to
be supressed.
The
.I \-u
option causes output to be flushed after each record.
The
.I \-n
option tells the program not to get any input, but to produce a
single output record.
Otherwise, if no files are given, the standard input is read.
.PP
Format files associate names with string and numeric fields
separated by literal information in a record.
A numeric field is given in a format file as a dollar sign, followed
by curly braces enclosing a variable name:
.PP
        This is a numeric field: ${vname}
.PP
A string variable is enclosed in parentheses:
.PP
        This is a string field: $(sname)
.PP
The program attempts to match literal information in
the input format to its input and assign string and numeric
fields accordingly.
If a string or numeric field variable appears more than once in
the input format, input values for the corresponding fields must
match (ie. have the same value) for the whole record to match.
Numeric values are allowed some deviation, on the order of 0.1%, but
string variables must match exactly.
Thus, dummy variables for "don't care" fields should be given unique
names so that they are not all required to take on the same value.
.PP
For each valid input record, an output record is produced
in its corresponding format.
Output field widths are given implicitly by the space occupied
in the format file, including the dollar sign and braces.
This makes it impossible to produce fields with fewer than four
characters.
If the
.I \-b
option is specified, input records must exactly match the
template.
By default, the character following each input field is used as
a delimiter.
This implies that string fields that are followed by white space
cannot contain strings with white space.
Also, numeric fields followed but not preceded by white space
will not accept numbers preceded by white space.
Adjacent input fields are advisable only with the
.I \-b
option.
Numeric output fields may contain expressions as well as variables.
A dollar sign may appear in a literal as two dollar signs ($$).
.PP
The definitions specified in
.I \-e
and
.I \-f
options relate numeric output fields to numeric input fields.
For the default record format, a field is a variable of the form
$N, where N is the column number, beginning with 1.
Output columns appear on the left-hand side of assignments, input
columns appear on the right-hand side.
.PP
A variable definition has the form:
.PP

        var = expression ;

.PP
Any instance of the variable in an expression will be replaced
with its definition.
.PP
An expression contains real numbers, variable names, function calls,
and the following operators:
.PP
        +  -  *  /  ^
.PP
Operators are evaluated left to right.
Powers have the highest precedence; multiplication and
division are evaluated before addition and subtraction.
Expressions can be grouped with parentheses.
All values are double precision real.
.PP
A function definition has the form:
.PP

        func(a1, a2, ..) = expression ;

.PP
The expression can contain instances of the function arguments
as well as other variables and functions.
Function names can be passed as arguments.
Recursive functions can be defined using calls to the defined
function or other functions calling the defined function.
.PP
The variable
.I cond,
if defined, will determine whether the current input record produces
an output record.
If
.I cond
is positive, output is produced.
If
.I cond
is less than or equal to zero, the record is skipped and no other expressions
are evaluated.
This provides a convenient method for avoiding inappropriate calculations.
The following library of pre-defined functions and variables is provided:
.TP 10n
.BR "in(n)"
Return the value for input column
.I n,
or the number of columns available in this record if
.I n
is 0.
This is an alternate way to get a column value instead of using
the $N notation, and is more flexible since it is programmable.
This function is disabled if an input format is used.
.TP
.BR "if(cond, then, else)"
if cond is greater than zero,
then is evaluated, otherwise else is evaluated.
This function is necessary for recursive definitions.
.TP
.BR "select(N, a1, a2, ..)"
return aN (N is rounded to the nearest integer).
This function provides array capabilities.
If
.I N
is zero, the number of available arguments is returned.
.TP
.BR "rand(x)"
compute a random number between 0 and 1 based on x.
.TP
.BR "floor(x)"
return largest integer not greater than x.
.TP
.BR "ceil(x)"
return smallest integer not less than x.
.TP
.BR "sqrt(x)"
return square root of x.
.TP
.BR "exp(x)"
compute e to the power of x (e approx = 2.718281828).
.TP
.BR "log(x)"
compute the logarithm of x to the base e.
.TP
.BR "log10(x)"
compute the logarithm of x to the base 10.
.TP
.BR PI
the ratio of a circle's circumference to its diameter.
.TP
.BR recno
the number of records recognized thus far.
.TP
.BR outno
the number or records output thus far (including this one).
.TP
.BR "sin(x), cos(x), tan(x)"
trigonometric functions.
.TP
.BR "asin(x), acos(x), atan(x)"
inverse trigonometric functions.
.TP
.BR "atan2(y, x)"
inverse tangent of y/x (range -pi to pi).
.SH EXAMPLE
To print the square root of column two in column one,
and column one times column three in column two:
.IP "" .2i
rcalc -e '$1=sqrt($2);$2=$1*$3' inputfile > outputfile
.SH AUTHOR
Greg Ward
.SH BUGS
String variables can only be used in input and output formats and
.I \-s
options, not in definitions.
.PP
Tabs count as single spaces inside fields.
.SH "SEE ALSO"
calc(1), cnt(1), ev(1), getinfo(1), lam(1), tabfunc(1), total(1)
Revision:	1.4
Committed:	Tue Dec 9 15:59:06 2003 UTC (20 years, 5 months ago) by greg
Branch:	MAIN
Changes since 1.3:	+1 -1 lines
Log Message:	Fixed RCSid specification
#	Content
1	.\" RCSid "$Id$"
2	.TH RCALC 1 4/6/99 RADIANCE
3	.SH NAME
4	rcalc - record calculator
5	.SH SYNOPSIS
6	.B rcalc
7	[
8	.B \-b
9	][
10	.B \-l
11	][
12	.B \-n
13	][
14	.B \-w
15	][
16	.B \-u
17	][
18	.B \-tS
19	][
20	.B "\-i format"
21	][
22	.B "\-o format"
23	][
24	.B "\-f source"
25	][
26	.B "\-e expr"
27	][
28	.B "\-s svar=sval"
29	]
30	file ..
31	.SH DESCRIPTION
32	.I Rcalc
33	transforms ``records'' from each
34	.I file
35	according to the given set of literal and relational information.
36	By default, records are separated by newlines, and contain
37	numeric fields separated by tabs.
38	The
39	.I \-tS
40	option is used to specify an alternate tab character.
41	.PP
42	A
43	.I \-i format
44	option specifies a template for an alternate
45	input record format.
46	.I Format
47	is interpreted as a specification string if it contains a dollar sign '$'.
48	Otherwise, it is interpreted as the name of the file containing
49	the format specification.
50	In either case, if the format does not end with a newline, one will be added
51	automatically.
52	A special form of the
53	.I \-i
54	option may be followed immediately by a 'd' or an 'f' and an optional
55	count, which defaults to 1, indicating the number of double or float
56	binary values to read per record on the input file.
57	If binary input is specified, no format string or file is needed.
58	.PP
59	A
60	.I \-o format
61	option specifies an alternate output record format.
62	It is interpreted the same as an input specification, except that
63	the special
64	.I \-od
65	or
66	.I \-of
67	options do not require a count, as this will be determined by the
68	number of output channels in the given expressions.
69	.PP
70	The variable and function definitions in each
71	.I \-f source
72	file are read and compiled.
73	The
74	.I \-e expr
75	option can be used to define variables on the command line.
76	Since many of the characters in an expression have special meaning
77	to the shell, it should usually be enclosed in single quotes.
78	The
79	.I \-s svar=sval
80	option can be used to assign a string variable a string value.
81	If this string variable appears in an input format, only records
82	with the specified value will be processed.
83	.PP
84	The
85	.I \-b
86	option instructs the program to accept only exact matches.
87	By default, tabs and spaces are ignored except
88	as field separators.
89	The
90	.I \-l
91	option instructs the program to ignore newlines in the input,
92	basically treating them the same as tabs and spaces.
93	Normally, the beginning of the input format matches the beginning of
94	a line, and the end of the format matches the end of a line.
95	With the
96	.I \-l
97	option, the input format can match anywhere on a line.
98	.PP
99	The
100	.I \-w
101	option causes non-fatal error messages (such as division by zero) to
102	be supressed.
103	The
104	.I \-u
105	option causes output to be flushed after each record.
106	The
107	.I \-n
108	option tells the program not to get any input, but to produce a
109	single output record.
110	Otherwise, if no files are given, the standard input is read.
111	.PP
112	Format files associate names with string and numeric fields
113	separated by literal information in a record.
114	A numeric field is given in a format file as a dollar sign, followed
115	by curly braces enclosing a variable name:
116	.PP
117	This is a numeric field: ${vname}
118	.PP
119	A string variable is enclosed in parentheses:
120	.PP
121	This is a string field: $(sname)
122	.PP
123	The program attempts to match literal information in
124	the input format to its input and assign string and numeric
125	fields accordingly.
126	If a string or numeric field variable appears more than once in
127	the input format, input values for the corresponding fields must
128	match (ie. have the same value) for the whole record to match.
129	Numeric values are allowed some deviation, on the order of 0.1%, but
130	string variables must match exactly.
131	Thus, dummy variables for "don't care" fields should be given unique
132	names so that they are not all required to take on the same value.
133	.PP
134	For each valid input record, an output record is produced
135	in its corresponding format.
136	Output field widths are given implicitly by the space occupied
137	in the format file, including the dollar sign and braces.
138	This makes it impossible to produce fields with fewer than four
139	characters.
140	If the
141	.I \-b
142	option is specified, input records must exactly match the
143	template.
144	By default, the character following each input field is used as
145	a delimiter.
146	This implies that string fields that are followed by white space
147	cannot contain strings with white space.
148	Also, numeric fields followed but not preceded by white space
149	will not accept numbers preceded by white space.
150	Adjacent input fields are advisable only with the
151	.I \-b
152	option.
153	Numeric output fields may contain expressions as well as variables.
154	A dollar sign may appear in a literal as two dollar signs ($$).
155	.PP
156	The definitions specified in
157	.I \-e
158	and
159	.I \-f
160	options relate numeric output fields to numeric input fields.
161	For the default record format, a field is a variable of the form
162	$N, where N is the column number, beginning with 1.
163	Output columns appear on the left-hand side of assignments, input
164	columns appear on the right-hand side.
165	.PP
166	A variable definition has the form:
167	.PP
168
169	var = expression ;
170
171	.PP
172	Any instance of the variable in an expression will be replaced
173	with its definition.
174	.PP
175	An expression contains real numbers, variable names, function calls,
176	and the following operators:
177	.PP
178	+ - * / ^
179	.PP
180	Operators are evaluated left to right.
181	Powers have the highest precedence; multiplication and
182	division are evaluated before addition and subtraction.
183	Expressions can be grouped with parentheses.
184	All values are double precision real.
185	.PP
186	A function definition has the form:
187	.PP
188
189	func(a1, a2, ..) = expression ;
190
191	.PP
192	The expression can contain instances of the function arguments
193	as well as other variables and functions.
194	Function names can be passed as arguments.
195	Recursive functions can be defined using calls to the defined
196	function or other functions calling the defined function.
197	.PP
198	The variable
199	.I cond,
200	if defined, will determine whether the current input record produces
201	an output record.
202	If
203	.I cond
204	is positive, output is produced.
205	If
206	.I cond
207	is less than or equal to zero, the record is skipped and no other expressions
208	are evaluated.
209	This provides a convenient method for avoiding inappropriate calculations.
210	The following library of pre-defined functions and variables is provided:
211	.TP 10n
212	.BR "in(n)"
213	Return the value for input column
214	.I n,
215	or the number of columns available in this record if
216	.I n
217	is 0.
218	This is an alternate way to get a column value instead of using
219	the $N notation, and is more flexible since it is programmable.
220	This function is disabled if an input format is used.
221	.TP
222	.BR "if(cond, then, else)"
223	if cond is greater than zero,
224	then is evaluated, otherwise else is evaluated.
225	This function is necessary for recursive definitions.
226	.TP
227	.BR "select(N, a1, a2, ..)"
228	return aN (N is rounded to the nearest integer).
229	This function provides array capabilities.
230	If
231	.I N
232	is zero, the number of available arguments is returned.
233	.TP
234	.BR "rand(x)"
235	compute a random number between 0 and 1 based on x.
236	.TP
237	.BR "floor(x)"
238	return largest integer not greater than x.
239	.TP
240	.BR "ceil(x)"
241	return smallest integer not less than x.
242	.TP
243	.BR "sqrt(x)"
244	return square root of x.
245	.TP
246	.BR "exp(x)"
247	compute e to the power of x (e approx = 2.718281828).
248	.TP
249	.BR "log(x)"
250	compute the logarithm of x to the base e.
251	.TP
252	.BR "log10(x)"
253	compute the logarithm of x to the base 10.
254	.TP
255	.BR PI
256	the ratio of a circle's circumference to its diameter.
257	.TP
258	.BR recno
259	the number of records recognized thus far.
260	.TP
261	.BR outno
262	the number or records output thus far (including this one).
263	.TP
264	.BR "sin(x), cos(x), tan(x)"
265	trigonometric functions.
266	.TP
267	.BR "asin(x), acos(x), atan(x)"
268	inverse trigonometric functions.
269	.TP
270	.BR "atan2(y, x)"
271	inverse tangent of y/x (range -pi to pi).
272	.SH EXAMPLE
273	To print the square root of column two in column one,
274	and column one times column three in column two:
275	.IP "" .2i
276	rcalc -e '$1=sqrt($2);$2=$1*$3' inputfile > outputfile
277	.SH AUTHOR
278	Greg Ward
279	.SH BUGS
280	String variables can only be used in input and output formats and
281	.I \-s
282	options, not in definitions.
283	.PP
284	Tabs count as single spaces inside fields.
285	.SH "SEE ALSO"
286	calc(1), cnt(1), ev(1), getinfo(1), lam(1), tabfunc(1), total(1)