Introduction

IBM(R) XL Fortran Advanced Edition V10.1 for Linux(R) is an optimizing, standards-based, command-line compiler for the Linux operating system, running on PowerPC(R) hardware with the PowerPC architecture. The XL Fortran compiler enables application developers to create and maintain optimized 32-bit and 64-bit applications for the Linux operating system. The compiler also offers a diversified portfolio of optimization techniques that allow an application developer to exploit the multi-layered architecture of the PowerPC processor.

The implementation of the Fortran programming language is intended to promote portability among different environments by enforcing conformance to language standards. A program that conforms strictly to its language specification will have maximum portability among different environments. In theory, a program that compiles correctly with one standards-conforming compiler will compile and execute correctly under all other conforming compilers, insofar as hardware differences permit. A program that correctly exploits the extensions to the programming language in which it is written can improve the efficiency of its object code.

XL Fortran Advanced Edition V10.1 for Linux can be used for large, complex, and computationally intensive programs. It also supports interlanguage calls with C/C++. For applications that require SIMD (single-instruction, multiple data) parallel processing, performance improvements can be achieved through optimization techniques, which may be less labor-intensive than vector programming. Many of the optimizations developed by IBM are controlled by compiler options and directives.