Questions tagged [fortran]

Fortran is a general purpose programming language widely used by the scientific computing community.

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9
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3answers
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How do I know if my code is being vectorized by the compiler?

As exemplified by Jed Brown's answer to Costs of lookups versus calculations, using vectorized vs non-vectorized floating point operations results in much faster code. Many modern compilers claim ...
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5answers
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Parallel Scientific Computation Software Development Language?

I want to develop a parallel scientific computation software from scratch. I want some thoughts on which language to start. The program involves reading/writing data to txt files and doing heavy ...
27
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How should I install a Fortran compiler on a Mac? (OS X 10.x, x >= 4)

Related question: State of the Mac OS in Scientific Computing and HPC A significant number of software packages in computational science are written in Fortran, and Fortran isn't going away. A ...
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6answers
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Are there open-source scientific libraries which use modern Fortran with OOP?

I've spent the last couple of months on coding a Fortran program for solving a particular PDE system (describes fluid flow/combustion). I tryed to use latest-standard Fortran and the new OOP ...
28
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8answers
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Which package should I use to wrap Modern Fortran Code with Python?

I know of, and have used f2py2e to wrap some old Fortran 77 code, but my understanding is that it does not work with newer Fortran 95 code. I've researched what I should use, and have come across ...
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Is C slower than Fortran on the spectral norm shootout (using gcc, intel and other compilers)?

The conclusion here: How much better are Fortran compilers really? is that gfortran and gcc are as fast for simple code. So I wanted try something more complicated. I took the spectral norm shootout ...
9
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4answers
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Are DAXPY, DCOPY, DSCAL overkills?

I have implemented CG in FORTRAN by linking it to Intel MKL. When there are statements like: (Refer Wikipedia) p=r; x=x+alpha*p r=r-alpha*Ap; or similar ...
19
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6answers
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How do I write dimensionally agnostic code?

I often find myself writing very similar code for one, two, and three dimensional versions of a given operation/algorithm. Maintaining all of these versions can become tedious. Simple code ...
14
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1answer
361 views

Is there a tool out there that can generate interval extensions of Fortran (or C) functions by parsing Fortran (or C) code?

Case studies in my PhD thesis require that I have interval extensions of Fortran subroutines in CHEMKIN-II (apologies for the link; it's the best one I could find for a package no longer distributed ...
10
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3answers
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Matrix exponential of a real asymmetric matrix with Fortran 95 and LAPACK

I recently asked a question along the same lines for skew-Hermitian matrices. Inspired by the success of that question, and after banging my head against a wall for a couple of hours, I'm looking at ...
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4answers
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Matrix exponential of a skew-Hermitian matrix with fortran 95 and LAPACK

I'm just getting tucked into fortran 95 for some quantum mechanics simulations. Honestly, I've been spoiled by Octave so I've taken matrix exponentiation for granted. Given a (small, $n\leq 36$) skew-...
78
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5answers
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How much better are Fortran compilers really?

This question is an extension of two discussions that came up recently in the replies to "C++ vs Fortran for HPC". And it is a bit more of a challenge than a question... One of the most often-heard ...
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2answers
446 views

Filtering a dataset to get a more uniform distribution for neural network training

I'm looking into using artificial neural networks (ANN) to predict the reaction rates in my fluid instead of solving the full system of stiff ODEs. Some people from my lab have already done some work ...
11
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2answers
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How to set double precision values in Fortran

Recently, I've encountered a bizarre problem with FORTRAN95. I initialized variables X and Y as follows: X=1.0 Y=0.1 Later I add them together and print the ...
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2answers
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How do I compile a program that contains both MPI and OPENMP

I have a fortran 90 code that distributes blocks of computations (from a matrix) to multiple nodes in a cluster using MPI, but in each node, the for loops are executed in parallel using openmp. I ...
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13answers
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C++ vs Fortran for HPC

In my computational science PhD program, we are working almost exclusively in C++ and Fortran. It seems like some professors prefer one over the other. I am wondering which one is 'better' or if one ...
12
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2answers
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How to work with function pointers in Fortran in scientific programs

Here is a typical usage of function pointers in C. I would like to do something similar in Fortran. I have some ideas, but I would like to know if there is some canonical way to do so. The function ...
23
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3answers
20k views

Intel Fortran Compiler: tips on optimization at compilation

I will start with my personal experience in our lab. Back in the ifort 9 and 10 days, we used to be quite aggressive with the optimizations, compiling with -O3 and processor specific flags (-xW -xSSE4....
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4answers
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What makes Fortran fast?

Fortran has a special place in numerical programming. You can certainly make good and fast software in other languages, but Fortran keeps performing very well despite its age. Moreover, it's easier to ...

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