• Vladimir Puzyrev added an answer:
    Linear solver choice (fortran, have compared dgesv, pardiso with matlab) for 6000*6000 non-symmetric sparse system, suggestions?

    Hi guys,

    Have posted several days ago on intel mkl forum and have not yet got any information. Hope someone here can share some experience or perspectives. Thank you all in advance!

    Have been looking for an efficient linear solver (to be used in my abaqus uamt) for middle sized (between 6000*6000 to 20000*2000) non-symmetric sparse (density between 0.6 and 0.8) system.

    I have compared PARDISO, DGESV and Matlab using randomly generated 6000*6000 matrix on my Linux desktop with i7-3720QM CPU @ 2.60GHz and 8G RAM, ifort version 16.0.2.  Matlab backslash took 2.x seconds, DGESV took 5.x seconds while PARDISO took 12.x seconds. This does not seem to be reasonable to me as I am expecting PARDISO to be faster than DGESV.  Can someone share some experience/perspective on this or provide some solutions for which solver to choose for this type of problem (I am hoping to get somewhat close to MATLAB backslash if possible)?

    The following is my PARDISO parameters and I also found that by manually setting mkl_set_num_threads to be 1 to 8 won't make any obvious change of the wall time? Is that reasonable or have I made something wrong?

        ALLOCATE( iparm ( 64 ) )
        iparm(1) = 1 ! no solver default
        iparm(2) = 3 ! fill-in reordering from METIS
        iparm(4) = 0 ! no iterative-direct algorithm
        iparm(5) = 0 ! no user fill-in reducing permutation
        iparm(6) = 0 ! =0 solution on the first n compoments of x
        iparm(8) = 1 ! numbers of iterative refinement steps
        iparm(10) = 13 ! perturbe the pivot elements with 1E-13
        iparm(11) = 1 ! use nonsymmetric permutation and scaling MPS
        iparm(13) = 1 ! maximum weighted matching algorithm is switched-off (default for symmetric). Try iparm(13) = 1 in case of inappropriate accuracy
        iparm(14) = 0 ! Output: number of perturbed pivots
        iparm(18) = -1 ! Output: number of nonzeros in the factor LU
        iparm(19) = -1 ! Output: Mflops for LU factorization
        iparm(20) = 0 ! Output: Numbers of CG Iterations
        iparm(27) = 1 ! check the integer arrays ia and ja

        error  = 0 ! initialize error flag
        msglvl = 0 ! print statistical information
        mtype  = 11 ! real and nonsymmetric

        call mkl_set_dynamic(0)
        call mkl_set_num_threads(2)

    I also attached two code if someone is interested in reproducing this problem, one is a MATLAB code (MatGen.m) which generates random non-symmetric sparse matrix A, and x and calculate b=A*x. A, n and x are written into file MatInp.dat as an input for the Fortran code adapted from the example code to  check the speed and accuracy of DGESV and PARDISO. 

    I appreciate your interest/feedback and discussions are very welcome! Thank you!



    Vladimir Puzyrev

    Hi Xiang,

    Then I guess Ivan is right in his comment above. Your main problem is in high matrix density.

  • Ejaz Haider added an answer:
    Can anyone send me subroutine fortran program for using in Aspen plus for the simulation of sulphuric acid plant?

    i am trying to simulate Sulfuric acid plant on aspen plus. For that i need a subroutine for inserting kinetics. Need expert assistance in this regard. Thanks a lot in advance.

    Ejaz Haider

    Please refer to Aspen Plus examples, There you can find Sulfuric Acid plant simulation and Fortran subroutines for user reaction kinetics.

    For example

    C:\Program Files\AspenTech\Aspen Plus (Version)\GUI\Examples\Sulfuric Acid


  • Olof Dahlberg added an answer:
    I need to find out TRUBAL Program. Can I know possible way to find this?

    "TRUBAL is a computer program for modelling the mechanical behavior of spheres in three dimensions. It is written in Fortran, and is freely available in source-code from for use on a micro-computer. " - Peter Cundall 

    Thank you very much.

    Olof Dahlberg

    Strack is still at University of Minnesota and Cundall is at Itasca.

    + 1 more attachment

  • Antonio Lucero added an answer:
    How can I get and use the structured programming precompiler IFTRAN?

    IFTRAN is a precompiler that produces FORTRAN code. It was developed in the 1970's.

    Antonio Lucero

    Thank you so much, Graeme.

    Long time no see!

    All the best.


  • Somkenechukwu Mamah added an answer:
    How can I give a time interval in Fortran 90?

    I want to make a water ON for 1 minutes and OFF for desirable minutes depending on temperature and relative humidity. The OFF interval will vary with the weather.

    Somkenechukwu Mamah

    Use  INTERVAL ARITHEMATIC library within your if-else statements.


    type(INTERVAL) X,Y


    C that's to loop over 1-10

    Y= the expression you want to remain ON or OFF

    write(6,*) Y

    Hope you will find this helpful, wish you all the best!

  • Liyuan Hu added an answer:
    Could anyone tell me where I can find some folding potential codes?

    Hello, every friend!

    I need to calculate the optical potential between two nuclei, so I've tried to find open source folding potential calculation codes.

    I have known that there are DFPOT and SPI-GENOA, but I haven't found their codes that can be used directly, i.e., where to download them?

    Thank you very much!

    Liyuan Hu

    Dear Prof. Rajiv Kumar,

     Thank you! The CPC library also have some corresponding codes.


  • Basanta Kumar Parida added an answer:
    Is FORTRAN program is helpful in solving Kuramoto-Sivasinsky equation?

    Solution of KS equation.

    Basanta Kumar Parida

    Thank you all.

  • Anibal Blanco added an answer:
    Why are physicists stuck with Fortran and not willing to move to Python with NumPy and Scipy?

    Nowadays all of the major Fortran related numerical calculus have exactly mapped equivalent libraries in more modern language framework like Numerical Python (NumPy) and Scientific Python (SciPy). 

    What keeps physicists stuck with Fortran?



    Scientific evidence?

    + 1 more attachment

    Anibal Blanco

    Python is slow?


  • Samuel Ogunwale added an answer:
    Aspen pllus the example of ultrafiltration membrane.. after running i got error "block membrane is not in mass balance. total flow rate is zero?

    need  to write Fortran code for aspen plus simulation but I'm practicing the ultrafiltration example I got the error. "Block membrane is not in mass balance... The total flow rate is zero..."  Please what can I do

    Samuel Ogunwale
    Alright Ejaz.. I think the problem is with V8.8 I'm using V8.6 and it is running fine... Thanks so much
  • Mongi Mhlongo added an answer:
    How to write a fortran code for eigenvalue Lippmann-Shwinger equation?

    Hello all.

    I am working on Deuteron Bound-State; Numerical Integral Equations and I need help finding a fortran code that calculates eigenvalues of Lippmann-Schwinger equation for deuteron bound states, prefarably one that follows Lanczos iterative scheme. Thank you

    Mongi Mhlongo

    Thank you Hasi Ray I have written the code

  • wu Shenghua added an answer:
    How might one fix an error in Abaqus with fortran subroutine?

    I installed Abaqus 6.12-3, Visual Studio(2010) and Fortran(11.1) in my local CAD machine. While running the simulation, I got below errors.

    1.Unable to locate compiler! Please verify your PATH settings and/or refer to Abaqus answer 4302.

    2.Upon submission through command prompt, run got terminated yielding the error” USER SUBROUTINE DFLUX IS MISSING”

    Please guide me to solve the problem.



  • wu Shenghua added an answer:
    "Problem during compilation" using UMAT in ABAQUS 6.14-1.Can someone please help?

    I am trying to implement the UMAT test code (attached as a snapshot and .for file) that is mentioned as an example in the ABAQUS manual, though unfortunately I'm getting an error -

    "Problem with compilation"

    on ABAQUS 6.14-1.
    To test, I simply make a shaft and input two Mechanical user properties and give it a density. I am using Visual Studio 2012 with Intel Parallel Studio 2016. Can someone please help me solve this problem?



    + 1 more attachment

  • Salman Ali Khan asked a question:
    Heat Transfer Subroutine for RPLUG in Aspen Plus?

    I need to calculate Heat Transfer Fortran Subroutine for RPLUG. I don't find any example or guidance. Could anyone please guide me how to calculate. I read Aspen User Models but i could not understand that.
    Thank You

  • Elena Galindez added an answer:
    What is the current software used to allocate optimal observer sampling effort within a commercial fleet?

    We are currently using a FORTRAN-based software developed in my institution, and I would like to compare its performance with other available software.

    Elena Galindez

    thank you Dr. Scarlato. 

  • Hans Rieder added an answer:
    Is FORTRAN a good choice for scientific computing?

    I am gonna start finite element programming for watershed runoff analysis so was wondering whether fortran is good??

    Hans Rieder


    To my opinion the programmatic consideration is as folllows: Fortran is a not dying language because it is practised in countless applications and widely used for scientific problems; Of course, the most of the applications can also be programmed in C, C++ and their derivatives; the advantage of this language family is the proximity to the assembly and the simplicity to get through all OSI-Levels,  just even to the lowest extremely hardware dependent layer.  In more than 35 years I have used nearly all standard languages such as Pascal, Fortran, C and C++ and other derivates; in my lecture “Signal Processing and Embedded Systems”, we use a so called "numerical C” language, which is optimized for Digital Signal Processors (in this case the SHARC family from Analog Devices). In all regarded applications, my focus is to explain the students in detail what the compiler is creating from the high Level language code in Assembler language for this DSP!

    Despite to all experiences, I think, that Fortran is very well suited for scientific, mathematical problems. My proposal: Decide it, do it and the rest is practice, practice and practice again.

  • Ejaz Haider added an answer:
    User Kinetics Fortran Subroutines for Aspen Plus?

    Does someone has any experience to write Fortran subroutines to customize Aspen Plus, Especially Kinetics Subroutine. I need to calculate FLUXM and FLUXS in user kinetics subroutine.
    Thank You

    Ejaz Haider

    @ Asma
    You don't need to install any external package if you want to work with Aspen custom modeler. Please complete the attached Manual to understand about Aspen custom modeler.

  • Negar Kamali added an answer:
    System error code 1073740940 when using UEL ?

    I'm trying to run an analysis with a simple UEL subroutine that I wrote and after compiling, linking, analyzing the input file and the subroutine suddenly it crashes with this error:

    Abaqus Error: The executable standard.exe
    aborted with system error code 1073740940.
    Please check the .dat, .msg, and .sta files for error messages if the files

    has anyone encountered this before? I can not find a bug in my code (I write out all the matrices and they're all correct) I also checked everything else that comes to my mind.

    P.S: I can run other subroutines to the completed stage

    Negar Kamali

    For those of you who still following this question and for future references,

    One other situation that I bumped into this error was that I didn't initiate one of my matrices.

    hope it helps

  • Abderrachid Hamrani added an answer:
    Any expert in Marciniak Kuczynski crash-worthiness analysis FORTRAN code?

    An overall FORTRAN code for Marciniak Kuczynski crashworthiness analysis model has been generated. The code is working fine but not upto the necessary expectations. Assistance from anyone who has expertise in this field is much appreciated.

    The code can be best shared through email.

    Abderrachid Hamrani

    You can send me the code to help you  (I'm not an expert but I will tray my best)

    Best wishes

  • Closed account added an answer:
    How can I create a Graphical User Interface for FORTRAN code?

    Hi all,

    I have developed a code using Fortan included in the Microsoft Visual Studio 2010. I would like to create a graphical user interface GUI for this code but I don`t know how to do that in easier manner.

    Could anyone please share his experience on such coding development ? is the Microsoft Visual Studio 2010 can do that or should I use other programming languages such Visual Basic, or Delphi or ... to do that ? I`m really confusing on how to start doing this and I would appreciate any suggestion and help.




    Are you searching for a graphical uset interface (GUI) or a plotting library? If you need a graphical user interface, you can do it easily (with visual studio). If you need a plotting library you can use DISLIN.


  • Boris L. Glebov added an answer:
    What are the best ways to learn FORTRAN swiftly and efficiently ?

    I would like to learn FORTRAN to build a solver for numerical difference techniques..so I would  be delighted to know where to start with and how to proceed.

    Boris L. Glebov

    Simon, you may well be right about GPU acceleration. It also falls under the parallelization caveat - it's only applicable to some problems even in principle.

  • Christoph Sontag added an answer:
    How to obtain the modified extended Huckel program from Anderson et.al ?

    I would apprecitate to get the source code in FORTRAN of the modified EHT program which allows some geometry optimization in organometal compounds. Any help is very much appreciated.

    Christoph Sontag

    Thanks for this hint - nevertheless it is more or less the original ICON program. The Anderson modification includes atom-atom repulsion terms, allowing for geometry-optimization.

  • Shiuh-Hwa Shyu added an answer:
    Which is the best alternative to Matlab?
    Matlab is an excellent software, but it is commercial and its price is very high. Other alternatives are available (Octave, Scilab, Freemat, ...) but each one has pros and cons. Is there a real competitor of Matlab?
    Shiuh-Hwa Shyu

    octave is almost 100% compatible with matlab

  • Shahram A.Dizaji added an answer:
    How can i link the abaqus(64-bit) and fortran ?

    I've tried all the solutions proposed but i did not succeed.
    I've used all versions of Abaqus.

    Is there a special case that I do not do?

    abaqus versions is : 6.12-3 , 6.13-1 , 6.13-4 , 6.14-1

    Fortran : intel fortran composer XE 2013

    Microsoft Visual studio 2012

    Shahram A.Dizaji

    I have explained the way yo should install the softwares respectively. You can look at may page in the questions part.

    If you have more questions please ask me.

  • Janusz Pudykiewicz added an answer:
    3D Fortran solver for Rayleigh benard convection in finite difference

    Hello, I am developing a simple 3D fortran solver in finite difference using Modified SMAC scheme. My domain is 2pi*2pi*1 as taken by S. Chandrasekhar. My equations are having non dimensional parameters as Reynolds Number, Rayleigh Number and Prandtl No.
    The code is running well but w- velocity contours(heating at bottom and cold at top) are coming only positive and negative alternatively and i am not getting rolls as expected. Can someone explain it.? Thanks in advance

    Janusz Pudykiewicz

    Hello Madhup,

    The problem with boundary conditions described in your question is quite well known. I will start from the simple scheme in which the derivatives inside of the domain are calculated using the central differences. On the lower and upper boundaries I will apply forward and backward differences respectively. This solution is usually acceptable for most of the problems including convection in the Cartesian and spherical geometry.

    If you are looking for more accurate solution I would like to suggest to read

    Strict Stability of High-Order Compact Implicit
    Finite-Difference Schemes: The Role of
    Boundary Conditions for Hyperbolic PDEs, I

    Saul S. Abarbanel and Alina E. Chertock

    Journal of Computational Physics
    160, 42–66 (2000)

    Based on my recent experience it looks that the both solutions can be used to solve the boundary value problems.

    In the past I was using often the book:

    Fundamentals of Computational Fluid Dynamics
    by Patrick J. Roache

    where all problems of computational fluid dynamics are discussed very clearly and in accessible manner.

    All the best in your calculations,


  • Michaelj Gunn added an answer:
    I'm getting numerical singularity and excessive distortion error when I'm compiling UMAT with Abaqus. Can anyone please help me with this?

    I'm working on the cyclic behaviour of soil using Cam clay model. For the material part, I found a umat code. When I ran my job without linking (using in built clay plasticity), I'm getting reasonable results. But when I'm linking with the UMAT, it is not even taking geostatic step and is showing excessive distortion. I'm attaching my .inp file and the umat code along with this. Please go through it and suggest me where I'm going wrong.

    + 1 more attachment

    Michaelj Gunn

    If this is your first attempt at using UMAT, try putting in elastic properties first/  print out a message from UMAT just to check the rest is working.  Actually this is good advice even if it isn't your first shot at using UMAT.

  • Ejaz Haider added an answer:
    How do I insert a reaction kinetic to Aspen Plus?

    I want to write a Fortran subroutine to insert a reaction kinetic to Aspen Plus, because the kinetic I have is not in the form as in Aspen Plus kinetics. As I don't know how to do that, I would be so grateful if someone send me a step by step procedure to follow.

    Many thanks.

    Ejaz Haider

    I also want to write a Fortran subroutine for reaction kinetic. If anyone could please send any material helpful for this, i will be thankful.

  • Shiv Narayan Nishad added an answer:
    Does anybody have the Fortran code for Lorenz 1996 model using RK4?
    Shiv Narayan Nishad

    Thank you Sir for your response, I have already written in 2014. 

  • Anji BABU Kapakayala added an answer:
    How do I write Fortran code for a simple harmonic oscillator using the velocity verlet method?

    Hi all,

    Can anybody explain how to write fortran code to solve simple harmonic oscillator by using velocity verlet method?????

    d2y/dx2  = -kx

    thanks in advance


    Anji BABU Kapakayala

    Thank you very much sir

  • Morton E. O'Kelly added an answer:
    Am writing some codes in fortran95, to read from a file and experiencing some problems, help?

    I wish to adapt my Fortran code to read these input files, then compile it. The adaptations should include:

    (1)    Have a loop for going through each line of input file

    (2)    Compute decimal year from year, month, day [DY]

    (3)    Compute colatitude from latitude [COLAT]

    (4)    Add the altitude to the CHAMP reference radius 6371.2 km [R]

    (5)    Use call subroutine igrf12syn(0,DY,2,R,COLAT, ELONG,X,Y,Z,F)

    I have attached my sample file and the programme


    + 1 more attachment

    Morton E. O'Kelly

    The main work is done subroutine igrf12syn. I think that what you are asking is how to call this repeatedly with all the the lines of data in your file? You need a loop --- read, call, read, call, ....

    You will have to do a little work to get your data in degrees and minutes as the program may expect data as 4 integers.... see this?

    WRITE(6,*) 'Enter latitude & longitude in degrees & minutes'
    WRITE(6,*) '(if either latitude or longitude is between -1'
    WRITE(6,*) 'and 0 degrees, enter the minutes as negative).'
    WRITE(6,*) 'Enter 4 integers'

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