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55-521: The history of PROJ dates back to the late 1970s, and the first release of PROJ was developed by Gerald Evenden in the early 1980s as a Ratfor program. It was based on the General Cartographic Transformation Package or GCTP, which consisted of Fortran subroutines that could be used to project geographic data. The second release of PROJ from 1985 was rewritten in C to run on UNIX systems. The third release of PROJ from 1990,

110-567: A Formula Translating System , and printed the name with small caps , Fortran . Other sources suggest the name stands for Formula Translator , or Formula Translation . Early IBM computers did not support lowercase letters, and the names of versions of the language through FORTRAN 77 were usually spelled in all- uppercase . FORTRAN 77 was the last version in which the Fortran character set included only uppercase letters. The official language standards for Fortran have referred to

165-490: A high-level programming language replacement. John Backus said during a 1979 interview with Think , the IBM employee magazine, "Much of my work has come from being lazy. I didn't like writing programs, and so, when I was working on the IBM 701 , writing programs for computing missile trajectories, I started work on a programming system to make it easier to write programs." The language

220-496: A card reader to be compiled. Punched card codes included no lower-case letters or many special characters, and special versions of the IBM 026 keypunch were offered that would correctly print the re-purposed special characters used in FORTRAN. Reflecting punched card input practice, Fortran programs were originally written in a fixed-column format, with the first 72 columns read into twelve 36-bit words. A letter "C" in column 1 caused

275-507: A character data type (Fortran 77), structured programming , array programming , modular programming , generic programming (Fortran 90), parallel computing ( Fortran 95 ), object-oriented programming (Fortran 2003), and concurrent programming (Fortran 2008). Since April 2024, Fortran has ranked among the top ten languages in the TIOBE index , a measure of the popularity of programming languages. The first manual for FORTRAN describes it as

330-577: A computer, an idea developed by J. Halcombe Laning and demonstrated in the Laning and Zierler system of 1952. A draft specification for The IBM Mathematical Formula Translating System was completed by November 1954. The first manual for FORTRAN appeared in October 1956, with the first FORTRAN compiler delivered in April 1957. Fortran produced efficient enough code for assembly language programmers to accept

385-452: A de facto standard), and Basic FORTRAN (based on FORTRAN II, but stripped of its machine-dependent features). The FORTRAN defined by the first standard, officially denoted X3.9-1966, became known as FORTRAN 66 (although many continued to term it FORTRAN IV, the language on which the standard was largely based). FORTRAN 66 effectively became the first industry-standard version of FORTRAN. FORTRAN 66 included: The above Fortran II version of

440-470: A limit of six characters in FORTRAN II. If A, B, and C cannot represent the sides of a triangle in plane geometry, then the program's execution will end with an error code of "STOP 1". Otherwise, an output line will be printed showing the input values for A, B, and C, followed by the computed AREA of the triangle as a floating-point number occupying ten spaces along the line of output and showing 2 digits after

495-413: A number of significant features to address many of the shortcomings of FORTRAN 66: In this revision of the standard, a number of features were removed or altered in a manner that might invalidate formerly standard-conforming programs. (Removal was the only allowable alternative to X3J3 at that time, since the concept of " deprecation " was not yet available for ANSI standards.) While most of the 24 items in

550-411: A problem. IBM's FORTRAN II appeared in 1958. The main enhancement was to support procedural programming by allowing user-written subroutines and functions which returned values with parameters passed by reference . The COMMON statement provided a way for subroutines to access common (or global ) variables. Six new statements were introduced: Over the next few years, FORTRAN II added support for

605-439: A program deck and add sequence numbers. Some early compilers, e.g., the IBM 650's, had additional restrictions due to limitations on their card readers. Keypunches could be programmed to tab to column 7 and skip out after column 72. Later compilers relaxed most fixed-format restrictions, and the requirement was eliminated in the Fortran 90 standard. Within the statement field, whitespace characters (blanks) were ignored outside

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660-409: A simple means for FORTRAN 77 programmers to issue POSIX system calls. Over 100 calls were defined in the document – allowing access to POSIX-compatible process control, signal handling, file system control, device control, procedure pointing, and stream I/O in a portable manner. The much-delayed successor to FORTRAN 77, informally known as Fortran 90 (and prior to that, Fortran 8X ),

715-456: A simplified, interpreted version of FORTRAN I (with only 12 statements not 32) for "load and go" operation was available (at least for the early IBM 1620 computer). Modern Fortran, and almost all later versions, are fully compiled, as done for other high-performance languages. The development of Fortran paralleled the early evolution of compiler technology , and many advances in the theory and design of compilers were specifically motivated by

770-487: A stack is maintained by software and the return address is stored on the stack before the call is made and restored after the call returns. Although not specified in FORTRAN 77, many F77 compilers supported recursion as an option, and the Burroughs mainframes , designed with recursion built-in, did so by default. It became a standard in Fortran 90 via the new keyword RECURSIVE. This program, for Heron's formula , reads data on

825-419: A standard method based on finite automata reduced run time to 12.723 seconds. With the availability of Fortran 77 , a successor named Ratfiv (Ratfor=rat4 => rat5=Ratfiv) could, with an option /f77, output a more readable Fortran 77 code: Initial Ratfor source code was ported to C in 1985 and improved to produce Fortran 77 code too. A git tree has been set in 2010 in order to revive ratfor . Although

880-432: A tape reel containing three 5-digit integers A, B, and C as input. There are no "type" declarations available: variables whose name starts with I, J, K, L, M, or N are "fixed-point" (i.e. integers), otherwise floating-point. Since integers are to be processed in this example, the names of the variables start with the letter "I". The name of a variable must start with a letter and can continue with both letters and digits, up to

935-414: A text literal. This allowed omitting spaces between tokens for brevity or including spaces within identifiers for clarity. For example, AVG OF X was a valid identifier, equivalent to AVGOFX , and 101010 DO101I = 1 , 101 was a valid statement, equivalent to 10101 DO 101 I = 1 , 101 because the zero in column 6 is treated as if it were a space (!), while 101010 DO101I = 1.101

990-489: Is a programming language implemented as a preprocessor for Fortran 66 . It provides modern control structures , unavailable in Fortran 66, to replace GOTOs and statement numbers. Ratfor provides the following kinds of flow-control statements, described by Kernighan and Plauger as "shamelessly stolen from the language C , developed for the UNIX operating system by D.M. Ritchie " ("Software Tools", p. 318): For example,

1045-491: Is a popular language for high-performance computing and is used for programs that benchmark and rank the world's fastest supercomputers . Fortran has evolved through numerous versions and dialects. In 1966, the American National Standards Institute (ANSI) developed a standard for Fortran to limit proliferation of compilers using slightly different syntax. Successive versions have added support for

1100-483: Is an enhanced version of the Ratfor programming language , a preprocessor for Fortran designed to give it C -like capabilities. Fortran was widely used for scientific programming but had very basic control-flow primitives ("do" and " goto ") and no " macro " facility which limited its expressiveness. The name of the language is a pun ( Ratfor (RATional FORtran) -> "Rat Four" -> "Rat Five" -> RatFiv ). Ratfiv

1155-419: Is determined by a random number generator suitably weighted according to whatever FREQUENCY statements have been provided. The first FORTRAN compiler reported diagnostic information by halting the program when an error was found and outputting an error code on its console. That code could be looked up by the programmer in an error messages table in the operator's manual, providing them with a brief description of

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1210-501: Is to prepare for section 5 a table of predecessors (PRED table) which enumerates the basic blocks and lists for every basic block each of the basic blocks which can be its immediate predecessor in flow, together with the absolute frequency of each such basic block link. This table is obtained by running the program once in Monte-Carlo fashion, in which the outcome of conditional transfers arising out of IF-type statements and computed GO TO's

1265-487: The DOUBLE PRECISION and COMPLEX data types. Early FORTRAN compilers supported no recursion in subroutines. Early computer architectures supported no concept of a stack, and when they did directly support subroutine calls, the return location was often stored in one fixed location adjacent to the subroutine code (e.g. the IBM 1130 ) or a specific machine register ( IBM 360 et seq ), which only allows recursion if

1320-481: The GNU C compiler had the ability to directly compile a Ratfor file (.r) without keeping a useless intermediate Fortran code (.f) ( gcc foo.r ), this functionality was lost in version 4 during the move in 2005 from f77 to GNU Fortran . The original source was available in . deb and . rpm forms at its original site, mirror.corbina.net/mandriva/, and its archive, www.dgate.org/ratfor/ are gone as of April, 2024. Ratfiv

1375-486: The IBM 7030 ("Stretch") computer, followed by versions for the IBM 7090 , IBM 7094 , and later for the IBM 1401 in 1966. By 1965, FORTRAN IV was supposed to be compliant with the standard being developed by the American Standards Association X3.4.3 FORTRAN Working Group. Between 1966 and 1968, IBM offered several FORTRAN IV compilers for its System/360 , each named by letters that indicated

1430-508: The Heron program needs several modifications to compile as a Fortran 66 program. Modifications include using the more machine independent versions of the READ and WRITE statements, and removal of the unneeded FLOATF type conversion functions. Though not required, the arithmetic IF statements can be re-written to use logical IF statements and expressions in a more structured fashion. After

1485-566: The Hollerith edit descriptors in the FORMAT statements with quoted strings. It also uses structured IF and END IF statements, rather than GOTO / CONTINUE . The development of a revised standard to succeed FORTRAN 77 would be repeatedly delayed as the standardization process struggled to keep up with rapid changes in computing and programming practice. In the meantime, as the "Standard FORTRAN" for nearly fifteen years, FORTRAN 77 would become

1540-522: The University of Waterloo's WATFOR and WATFIV were created to simplify the complex compile and link processes of earlier compilers. In the FORTRAN IV programming environment of the era, except for that used on Control Data Corporation (CDC) systems, only one instruction was placed per line. The CDC version allowed for multiple instructions per line if separated by a $ (dollar) character. The FORTRAN sheet

1595-468: The case of lexical analysis, well-known techniques do seem to offer efficiency while retaining the simplicity, ease of coding and modularity of ad hoc methods." (CSD-TR236). In comparison to the Ratfor preprocessor on a program of 3000 source lines running on a CDC 6500 system took 185.470 CPU seconds. That was cut by 50% when binary search was used in the Ratfor code. Rewriting the ad hoc lexical scanner using

1650-484: The conflict list (see Appendix A2 of X3.9-1978) addressed loopholes or pathological cases permitted by the prior standard but rarely used, a small number of specific capabilities were deliberately removed, such as: A Fortran 77 version of the Heron program requires no modifications to the Fortran 66 version. However this example demonstrates additional cleanup of the I/O statements, including using list-directed I/O, and replacing

1705-551: The decimal point, the .2 in F10.2 of the FORMAT statement with label 601. IBM also developed a FORTRAN III in 1958 that allowed for inline assembly code among other features; however, this version was never released as a product. Like the 704 FORTRAN and FORTRAN II, FORTRAN III included machine-dependent features that made code written in it unportable from machine to machine. Early versions of FORTRAN provided by other vendors suffered from

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1760-607: The early history of FORTRAN was the decision by the American Standards Association (now American National Standards Institute (ANSI)) to form a committee sponsored by the Business Equipment Manufacturers Association (BEMA) to develop an American Standard Fortran . The resulting two standards, approved in March 1966, defined two languages, FORTRAN (based on FORTRAN IV, which had served as

1815-432: The entire card to be treated as a comment and ignored by the compiler. Otherwise, the columns of the card were divided into four fields: Columns 73 to 80 could therefore be used for identification information, such as punching a sequence number or text, which could be used to re-order cards if a stack of cards was dropped; though in practice this was reserved for stable, production programs. An IBM 519 could be used to copy

1870-573: The following code might be translated as The version of Ratfor in Software Tools is written in Ratfor, as are the sample programs, and inasmuch as its own translation to Fortran is available, it can be ported to any Fortran system. Ratfor source code file names end in .r or .rat. Ratfor was designed and implemented by Brian Kernighan at Bell Telephone Laboratories in 1974, and described in Software—;Practice & Experience in 1975. It

1925-501: The generated code, the results of which were used to optimize the placement of basic blocks in memory—a very sophisticated optimization for its time. The Monte Carlo technique is documented in Backus et al.'s paper on this original implementation, The FORTRAN Automatic Coding System : The fundamental unit of program is the basic block ; a basic block is a stretch of program which has one entry point and one exit point. The purpose of section 4

1980-521: The historically most important dialect. An important practical extension to FORTRAN 77 was the release of MIL-STD-1753 in 1978. This specification, developed by the U.S. Department of Defense , standardized a number of features implemented by most FORTRAN 77 compilers but not included in the ANSI FORTRAN 77 standard. These features would eventually be incorporated into the Fortran 90 standard. The IEEE 1003.9 POSIX Standard, released in 1991, provided

2035-451: The increasing popularity of FORTRAN spurred competing computer manufacturers to provide FORTRAN compilers for their machines, so that by 1963 over 40 FORTRAN compilers existed. FORTRAN was provided for the IBM 1401 computer by an innovative 63-phase compiler that ran entirely in its core memory of only 8000 (six-bit) characters. The compiler could be run from tape, or from a 2200-card deck; it used no further tape or disk storage. It kept

2090-526: The language as "Fortran" with initial caps since Fortran 90. In late 1953, John W. Backus submitted a proposal to his superiors at IBM to develop a more practical alternative to assembly language for programming their IBM 704 mainframe computer . Backus' historic FORTRAN team consisted of programmers Richard Goldberg, Sheldon F. Best, Harlan Herrick, Peter Sheridan, Roy Nutt , Robert Nelson, Irving Ziller, Harold Stern, Lois Haibt , and David Sayre . Its concepts included easier entry of equations into

2145-656: The minimum amount of memory the compiler needed to run. The letters (F, G, H) matched the codes used with System/360 model numbers to indicate memory size, each letter increment being a factor of two larger: Digital Equipment Corporation maintained DECSYSTEM-10 Fortran IV (F40) for PDP-10 from 1967 to 1975. Compilers were also available for the UNIVAC 1100 series and the Control Data 6000 series and 7000 series systems. At about this time FORTRAN IV had started to become an important educational tool and implementations such as

2200-465: The need to generate efficient code for Fortran programs. The initial release of FORTRAN for the IBM 704 contained 32 statements , including: The arithmetic IF statement was reminiscent of (but not readily implementable by) a three-way comparison instruction (CAS—Compare Accumulator with Storage) available on the 704. The statement provided the only way to compare numbers—by testing their difference, with an attendant risk of overflow. This deficiency

2255-420: The problem. Later, an error-handling subroutine to handle user errors such as division by zero, developed by NASA, was incorporated, informing users of which line of code contained the error. Before the development of disk files, text editors and terminals, programs were most often entered on a keypunch keyboard onto 80-column punched cards , one line to a card. The resulting deck of cards would be fed into

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2310-519: The program in memory and loaded overlays that gradually transformed it, in place, into executable form, as described by Haines. This article was reprinted, edited, in both editions of Anatomy of a Compiler and in the IBM manual "Fortran Specifications and Operating Procedures, IBM 1401". The executable form was not entirely machine language ; rather, floating-point arithmetic, sub-scripting, input/output, and function references were interpreted, preceding UCSD Pascal P-code by two decades. GOTRAN ,

2365-601: The release of the FORTRAN 66 standard, compiler vendors introduced several extensions to Standard Fortran , prompting ANSI committee X3J3 in 1969 to begin work on revising the 1966 standard, under sponsorship of CBEMA , the Computer Business Equipment Manufacturers Association (formerly BEMA). Final drafts of this revised standard circulated in 1977, leading to formal approval of the new FORTRAN standard in April 1978. The new standard, called FORTRAN 77 and officially denoted X3.9-1978, added

2420-626: The release of version 5.0 in February 2018, the software was renamed to PROJ, removing version four (".4") from the name. With the acquisition of the proj.org domain name in June 2019, the project was also renamed as PROJ. The string format that PROJ uses to describe coordinate systems and transformations, proj string or proj.4 string , is widely used beyond PROJ proper. A wide variety of ports or bindings in other programming languages have been developed. Ratfor Ratfor (short for Rational Fortran )

2475-428: The same disadvantage. IBM began development of FORTRAN IV in 1961 as a result of customer demands. FORTRAN IV removed the machine-dependent features of FORTRAN II (such as READ INPUT TAPE ), while adding new features such as a LOGICAL data type , logical Boolean expressions , and the logical IF statement as an alternative to the arithmetic IF statement. FORTRAN IV was eventually released in 1962, first for

2530-480: Was also standard-conforming under Fortran 90, and either standard should have been usable to define its behavior. A small set of features were identified as "obsolescent" and were expected to be removed in a future standard. All of the functionalities of these early-version features can be performed by newer Fortran features. Some are kept to simplify porting of old programs but many were deleted in Fortran 95. Fortran 95 , published officially as ISO/IEC 1539-1:1997,

2585-495: Was developed by Bill Wood at the Institute for Cancer Research , Philadelphia , PA in the early 1980s and released on several DECUS (Digital Equipment Users Group) SIG (Special Interest Group) tapes. It is based on the original Ratfor by B. Kernighan and P. J. Plauger , with rewrites and enhancements by David Hanson and friends (U. of Arizona), Joe Sventek and Debbie Scherrer ( Lawrence Berkeley National Laboratory ). Ratfiv V2.1

2640-729: Was distributed on the DECUS RSX82a SIG tape. F77 Fortran ( / ˈ f ɔːr t r æ n / ; formerly FORTRAN ) is a third generation , compiled , imperative programming language that is especially suited to numeric computation and scientific computing . Fortran was originally developed by IBM . It first compiled correctly in 1958. Fortran computer programs have been written to support scientific and engineering applications, such as numerical weather prediction , finite element analysis , computational fluid dynamics , plasma physics , geophysics , computational physics , crystallography and computational chemistry . It

2695-430: Was divided into four fields, as described above. Two compilers of the time, IBM "G" and UNIVAC, allowed comments to be written on the same line as instructions, separated by a special character: "master space": V (perforations 7 and 8) for UNIVAC and perforations 12/11/0/7/8/9 (hexadecimal FF) for IBM. These comments were not to be inserted in the middle of continuation cards. Perhaps the most significant development in

2750-538: Was expanded to support approximately 70 cartographic projections. Evenden further developed a fourth release in 1994, named PROJ.4. The last version maintained by Evenden was 4.3, released on September 24, 1995. After over four years of inactivity, Frank Warmerdam became the new maintainer and released version 4.4 on March 21, 2000. As of May 2008, PROJ became part of the MetaCRS project, a confederation of coordinate systems related projects under incubation with OSGeo . With

2805-410: Was finally released as ISO/IEC standard 1539:1991 in 1991 and an ANSI Standard in 1992. In addition to changing the official spelling from FORTRAN to Fortran, this major revision added many new features to reflect the significant changes in programming practice that had evolved since the 1978 standard: Unlike the prior revision, Fortran 90 removed no features. Any standard-conforming FORTRAN 77 program

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2860-412: Was instead 10101 DO101I = 1.101 , the assignment of 1.101 to a variable called DO101I . Note the slight visual difference between a comma and a period. Hollerith strings , originally allowed only in FORMAT and DATA statements, were prefixed by a character count and the letter H (e.g., 26HTHIS IS ALPHANUMERIC DATA. ), allowing blanks to be retained within the character string. Miscounts were

2915-411: Was later overcome by "logical" facilities introduced in FORTRAN IV. The FREQUENCY statement was used originally (and optionally) to give branch probabilities for the three branch cases of the arithmetic IF statement. It could also be used to suggest how many iterations a DO loop might run. The first FORTRAN compiler used this weighting to perform at compile time a Monte Carlo simulation of

2970-449: Was used in the book "Software Tools" ( Kernighan and Plauger , 1976). In 1977, at Purdue University , an improved version of the Ratfor preprocessor was written. It was called Mouse4, as it was smaller and faster than Ratfor. A published document by Dr. Douglas Comer , professor at Purdue, concluded "contrary to the evidence exhibited by the designer of Ratfor, sequential search is often inadequate for production software. Furthermore, in

3025-454: Was widely adopted by scientists for writing numerically intensive programs, which encouraged compiler writers to produce compilers that could generate faster and more efficient code. The inclusion of a complex number data type in the language made Fortran especially suited to technical applications such as electrical engineering. By 1960, versions of FORTRAN were available for the IBM 709 , 650 , 1620 , and 7090 computers. Significantly,

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