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The previous American National Standards Institute (ANSI) FORTRAN standard release, FORTRAN 77 (X3.9-1978), was written to promote portability of FORTRAN programs between different platforms. It didn't invent new language components, but instead incorporated good features that were already available in production compilers. Unlike FORTRAN 77, FORTRAN 90 (ANSI X3.198-1992) brings new extensions and features to the language. Some of these just bring FORTRAN up to date with newer languages like C (dynamic memory allocation, scoping rules) and C++ (generic function interfaces). But some of the new features are unique to FORTRAN (array operations). Interestingly, while the FORTRAN 90 specification was being developed, the dominant high performance computer architectures were scalable SIMD systems such as the Connection Machine and shared-memory vector-parallel processor systems from companies like Cray Research.

FORTRAN 90 does a surprisingly good job of meeting the needs of these very different architectures. Its features also map reasonably well onto the new shared uniform memory multiprocessors. However, as we will see later, FORTRAN 90 alone is not yet sufficient to meet the needs of the scalable distributed and nonuniform access memory systems that are becoming dominant at the high end of computing.

The FORTRAN 90 extensions to FORTRAN 77 include:

  • Array constructs
  • Dynamic memory allocation and automatic variables
  • Pointers
  • New data types, structures
  • New intrinsic functions, including many that operate on vectors or matrices
  • New control structures, such as a WHERE statement
  • Enhanced procedure interfaces

Fortran 90 array constructs

With FORTRAN 90 array constructs, you can specify whole arrays or array sections as the participants in unary and binary operations. These constructs are a key feature for "unserializing" applications so that they are better suited to vector computers and parallel processors. For example, say you wish to add two vectors, A and B. In FORTRAN 90, you can express this as a simple addition operation, rather than a traditional loop. That is, you can write:


A = A + B

instead of the traditional FORTRAN 77 loop:


DO I=1,N A(I) = A(I) + B(I)ENDDO

The code generated by the compiler on your workstation may not look any different, but for some of the parallel machines available now and workstations just around the corner, the difference are significant. The FORTRAN 90 version states explicitly that the computations can be performed in any order, including all in parallel at the same time.

One important effect of this is that if the FORTRAN 90 version experienced a floating-point fault adding element 17, and you were to look at the memory in a debugger, it would be perfectly legal for element 27 to be already computed.

You are not limited to one-dimensional arrays. For instance, the element-wise addition of two two-dimensional arrays could be stated like this: Just in case you are wondering, A*B gives you an element-wise multiplication of array members­­— not matrix multiplication. That is covered by a FORTRAN 90 intrinsic function.

Questions & Answers

what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
Daniel
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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Source:  OpenStax, High performance computing. OpenStax CNX. Aug 25, 2010 Download for free at http://cnx.org/content/col11136/1.5
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