section r of routines in std.i

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# functions in std.i - r

 random ``` random(dimension_list) random_seed, seed returns an array of random double values with the given DIMENSION_LIST (nil for a scalar result), uniformly distributed on the interval from 0.0 to 1.0. The algorithm is from Press and Teukolsky, Computers in Physics, vol. 6, no. 5, Sep/Oct 1992 (ran2). They offer a reward of \$1000 to anyone who can exhibit a statistical test that this random number generator fails in a "non-trivial" way. The random_seed call reinitializes the random number sequence; SEED should be between 0.0 and 1.0 non-inclusive; if SEED is omitted, nil, or out of range, the sequence is reinitialized as when Yorick starts. The numbers are actually at the centers of 2147483562 equal width bins on the interval [0,1]. Although only these 2 billion numbers are possible, the period of the generator is roughly 2.3e18. builtin function, documented at i0/std.i line 667 ``` SEE ALSO: randomize

 random_seed ``` random_seed builtin function, documented at i0/std.i line 667 ``` SEE random

 randomize ``` randomize randomize() set the seed for random "randomly" (based on the timer clock and the current state of random). As a function, returns the value of the seed passed to random_seed. interpreted function, defined at i0/std.i line 689 ``` SEE ALSO: random,   random_seed

 rdline ``` rdline(f) or rdline(f, n, prompt= pstring) returns next line from stream F (stdin if F nil). If N is non-nil, returns a string array containing the next N lines of F. If end-of-file occurs, rdline returns nil strings. If F is nil, uses the PSTRING to prompt for input (default "read> "). builtin function, documented at i0/std.i line 1348 ``` SEE ALSO: read,   open,   close,   bookmark,   backup,   read_n

 re_part ``` re_part(z) returns the real part of its argument. (Same as double(z).) Unlike z.re, works if z is not complex. keyword, defined at i0/std.i line 651 ```

 read ``` n= read(f, format=fstring, obj1, obj2, ...) or n= read(prompt= pstring, format=fstring, obj1, obj2, ...) or n= sread(source, format=fstring, obj1, obj2, ...) reads text from I/O stream F (1st form), or from the keyboard (2nd form), or from the string or string array SOURCE (3rd form), interprets it according to the optional FSTRING, and uses that interpretation to assign values to OBJ1, OBJ2, ... If the input is taken from the keyboard, the optional prompt PSTRING (default "read> ") is printed before each line is read. The Yorick write function does not interact with the read function -- writes are always to end-of-file, and do not affect the sequence of lines returned by read. The backup (and bookmark) function is the only way to change the sequence of lines returned by read. There must be one non-supressed conversion specifier (see below) in FSTRING for each OBJ to be read; the type of the conversion specifier must generally match the type of the OBJ. That is, an integer OBJ requires an integer specifier (d, i, o, u, or x) in FSTRING, a real OBJ requires a real specifier (e, f, or g), and a string OBJ requires a string specifier (s or []). An OBJ may not be complex, a pointer, a structure instance, or any non- array Yorick object. If FSTRING is not supplied, or if it has fewer conversion specifiers than the number of OBJ arguments, then Yorick supplies default specifiers ("%ld" for integers, "%lg" for reals, and "%s" for strings). If FSTRING contains more specifiers than there are OBJ arguments, the part of FSTRING beginning with the first specifier with no OBJ is ignored. The OBJ may be scalar or arrays, but the dimensions of every OBJ must be identical. If the OBJ are arrays, Yorick behaves as if the read were called in a loop numberof(OBJ1) times, filling one array element of each of the OBJ according to FSTRING on each pass through the loop. (Note that this behavior includes the case of reading columns of numbers by a single call to read.) The return value N is the total number of scalar assignments which were made as a result of this call. (If there were 4 OBJ arguments, and each was an array with 17 elements, a return value of N==35 would mean the following: The first 8 elements of OBJ1, OBJ2, OBJ3, and OBJ4 were read, and the 9th element of OBJ1, OBJ2, and OBJ3 was read.) The read function sets any elements of the OBJ which were not read to zero -- hence, independent of the returned N, the all of the old data in the OBJ arguments is overwritten. The read or sread functions continue reading until either: (1) all elements of all OBJ have been filled, or (2) end-of-file (or end of SOURCE for sread) is reached ("input failure"), or (3) part of FSTRING or a conversion specifier supplied by default fails to match the source text ("matching failure"). The FSTRING is composed of a series of "directives" which are (1) whitespace -- means to skip any amount of whitespace in the source text (2) characters other than whitespace and % -- must match the characters in the source text exactly, or matching failure occurs and the read operation stops (3) conversion specifiers beginning with % and ending with a character specifying the type of conversion -- optionally skip whitespace, then convert as many characters as continue to "look like" the conversion type, possibly producing a matching failure The conversion specifier is of the form %*WSC, where: is either the character '*' or not present A specifier beginning with %* does not correspond to any of the OBJ; the converted value will be discarded. W is either a positive decimal integer specifying the maximum field width (not including any skipped leading whitespace), or not present if any number of characters up to end-of-line is acceptable. S is either one of the characters 'h', 'l', or 'L', or not present. Yorick allows this for compatibility with the C library functions, but ignores it. C is a character specifying the type of conversion: d - decimal integer i - decimal, octal (leading 0), or hex (leading 0x) integer o - octal integer u - unsigned decimal integer (same as d for Yorick) x, X - hex integer e, f, g, E, G - floating point real s - string of non-whitespace characters [xxx] - (xxx is any sequence of characters) longest string of characters matching those in the list [^xxx] - longest string of characters NOT matching those in the list (this is how you can extend %s to be delimited by something other than whitespace) % - the ordinary % character; complete conversion specification must be "%%" The read function is modeled on the ANSI standard C library fscanf and sscanf functions, but differs in several respects: (1) Yorick's read cannot handle the %c, %p, or %n conversion specifiers in FSTRING. (2) Yorick's read never results in a portion of a line being read -- any unused part of a line is simply discarded (end FSTRING with "%[^\n]" if you want to save the trailing part of an input line). (3) As a side effect of (2), there are some differences between fscanf and Yorick's read in how whitespace extending across newlines is handled. builtin function, documented at i0/std.i line 1242 ``` SEE ALSO: rdline,   write,   open,   close,   bookmark,   backup,   save,   restore,   read_n

 read_clog ``` file= read_clog(file, clog_name) raw routine to set the binary data structure of FILE according to the text description in the Contents Log file CLOG_NAME. builtin function, documented at i0/std.i line 1747 ```

 read_n ``` read_n, f, n0, n1, n2, ... grabs the next numbers N0, N1, N2, ... from file F, skipping over any whitespace, comma, semicolon, or colon delimited tokens which are not numbers. (Actually, only the first and last characters of the token have to look like a number -- 4xxx3 would be read as 4.) ***WARNING*** at most ten Ns are allowed The Ns can be arrays, provided all have the same dimensions. interpreted function, defined at i0/std.i line 1358 ``` SEE ALSO: read,   rdline

 recover_file ``` recover_file, filename or recover_file, filename, clogfile writes the descriptive information at the end of a corrupted binary file FILENAME from its Contents Log file CLOGFILE, which is FILENAME+"L" by default. interpreted function, defined at i0/std.i line 1753 ```

 remove ``` remove builtin function, documented at i0/std.i line 1234 ``` SEE rename

 rename ``` rename, old_filename, new_filename remove filename rename or remove a file. builtin function, documented at i0/std.i line 1234 ``` SEE ALSO: open,   close,   openb

 require ``` require builtin function, documented at i0/std.i line 1483 ``` SEE include

 reshape ``` reshape, reference, address, type, dimension_list or reshape, reference, type, dimension_list or reshape, reference The REFERENCE must be an unadorned variable, not an expression; reshape sets this variable to an LValue at the specified ADDRESS with the specified TYPE and DIMENSION_LIST. (See the array function documentation for acceptable DIMENSION_LIST formats.) If ADDRESS is an integer (e.g.- a long), the programmer is responsible for assuring that the data at ADDRESS is valid. If ADDRESS is a (Yorick) pointer, Yorick will assure that the data pointed to will not be discarded, and the reshape will fail if TYPE and DIMENSION_LIST extend beyond the pointee bounds. In the second form, ADDRESS is taken to be &REFERENCE; that is, the TYPE and DIMENSION_LIST of the variable are changed without doing any type conversion. In the third form, REFERENCE is set to nil ([]). (Simple redefinition will not work on a variable defined using reshape.) WARNING: There are almost no situations for which reshape is the correct operation. See reform in Y_SITE/i/string.i. builtin function, documented at i0/std.i line 264 ``` SEE ALSO: array,   dimsof,   numberof,   is_array,   eq_nocopy

 restore ``` restore builtin function, documented at i0/std.i line 2178 ``` SEE save

 rmdir ``` rmdir builtin function, documented at i0/std.i line 1571 ``` SEE mkdir