Input / Output (I/O) performance can be a significant factor in overall program performance. The way you write I/O statements can make a big difference. Consider the following example: subroutine sub(x, n) real x(n) do i = 1, n, 2 write (unit=11) x(i) enddo end subroutine The I/O in sub might not be as fast as you'd like. This is due to the accumulation of the overhead for each write statement. The write statement above has to do some preparation work before it can actually write anything. It also has to do some cleanup work after it... [More]
Our colleague Jim Xia recently coauthored a new book: Scientific Software Design: The Object-Oriented Way (ISBN: 978-0521888134). The book is a great example of how to use the object-oriented features of Fortran 2003 in scientific design patterns. BTW, the examples in the book compile with XL Fortran. The Back Cover: This book concerns software design. Although many current discussions of scientific programming focus on scalable performance, this book focuses on scalable design. The authors analyze how the structure of a package determines... [More]
When the compiler knows that an array occupies a contiguous block of memory, it can perform optimizations based on memory layout. Explicit shape arrays, assumed-size arrays and allocatable arrays occupy contiguous blocks of memory. For array pointers and assumed shape arrays, the compiler cannot determine at compile time if it is the case. In the latest AIX XL Fortran compiler, -qassert=contiguous was introduced to allow the programmer to indicate to the compiler that: * all array pointers are pointer associated with contiguous targets. *... [More]
Check-out this tutorial to learn how to use the interoperability features of the IBM XL Fortran and the IBM XL C/C++ compiler to integrate Fortran, C and Java source code into an application. The demonstration shows how to call Java source routines from Fortran and vice versa. Interoperability is useful for integrating parts written in different languages into an application. This enables developers to take advantage of language best situated for the job or easily integrate legacy assets into a new application. Interoperability of IBM XL... [More]
Check out new exercises in the Power sandbox. You can find them below. You can learn about compiling with a list of options defined in a file, debugging optimized code, new OpenMP3.1 constructs, performance benefits of using F2008 CONTIGUOUS attribute and the F2008 BLOCK construct. Optimize server performance and programmer productivity with IBM
compilers Compile with a list of options defined in a file Debugging optimized XL Fortran code New and enhanced atomic constructs in OpenMP 3.1 The final clause in OpenMP 3.1 with the... [More]
In the past, the intrinsic procedures REAL(z) and AIMAG(z) (where z is of type complex) were used to get the real part and imaginary part of z. For example, COMPLEX :: z = (3.2, 2.1) REAL(z) has the value 3.2. AIMAG(z) has the value 2.1. In Fortran 2008, you can use the complex part designators with the %RE and %IM selectors instead; that is, z % RE has the value 3.2. z % IM has the value 2.1. You might benefit from the direct access to the real or imaginary part of complex entities by using the complex part designators as variables in... [More]
New and enhanced features in XL Fortran Version 14.1 include support of language
features that you can use to port code easily when moving to IBM Power Systems,
as well as improved compilation time at commonly used optimization levels. This
article for those who have some experience with previous versions of XL Fortran
gives the details and describes other highlights. Read more .
Looking to see and learn about the latest compiler enhancements in XL Fortran on AIX and Linux. Download a trial. Here is quick recap of some of the highlights of these new compilers: Compliance to ISO programming language standards including the Fortran 2003
standard and partial support for the Fortran 2008 standard Support for the OpenMP 3.1 industry specification Compile-time performance and scalability improvements Enhancements to the diagnostic reports that can help you identify
opportunities to improve the performance of your... [More]
Fortran Compilers are
now live on the Request for Enhancement (RFE) Community. It is a great
place where you can collaborate with development teams and other product users.
Our development team will review your RFE and provide status updates throughout
its lifecycle. Here is the link to the Community: Fortran RFE Looking forward to
hearing from you.
The June 2012 PTF for XL Fortran for AIX, V13.1 is now available at the following links and on Fix Central : June 2012 Update for XL Fortran for Linux, V13.1 June 2012 Update for XL Fortran Runtime for Linux, V13.1 Can't find the updates for your compilers? Check out our Fortran compilers latest updates page here .
you know that the compiler you use can impact whether or not you
achieve optimal performance from all parts of your systems.
Organizations often overlook the importance of compilers, often running
new high-powered servers with outdated compilers that limit the servers’
potential. Or failing to update compilers that can improve the
efficiency of existing hardware investments as more advanced versions
are released. In practical terms,this translates into greater power
consumption, slower response times,numerous administrative... [More]
If you are using the Parallel Environment's (PE) mpi module with an older version of the XL Fortran compiler , you might hit this error message: 1514-220 (S) Module symbol file for module mpi is in a format not recognized by this compiler. Please compile the module with this
compiler. The mpi module was generated using XL Fortran 12.1, so it's incompatible with earlier versions of XL Fortran. We recently published a technote about this. Consider upgrading to take advantage of the extra type-checking offered by this module. If you're... [More]
Check out updated exercises in the Power sandbox. You can find them below. You can learn about tracking compiler use, performance,
auto-vectorization, optimization, interoperability, and reporting Optimize server performance and programmer productivity with IBM
compilers Learn about tracking IBM XL C/C++ and Fortran compiler utilization Enhanced performance with new XL C/C++ and Fortran compilers Explore auto-vectorization Discover uninitialized floating point and integer variables Interoperability of IBM XL Fortran, IBM XL... [More]
The July 2012 PTF for XL Fortran for AIX, V13.1 (VRMF: 18.104.22.168) is now available at the following links and on Fix Central . July 2012 PTF for XL Fortran for AIX, V13.1 July 2012 PTF for XL Fortran Runtime for AIX, V13.1 Can't find the updates for your compilers? Check out our Fortran compilers latest updates page here .
Check out this webinar by IBM Systems Magazine about Smart Tools on IBM i, AIX, and Linux for Faster Time to Market Get an early look at the next version of Rational's offerings for Power Systems. New advancements in compilers and significantly enhanced development tools will give your organization a competitive advantage! Listen to the replay .