Fortran Definition and 858 Threads

trying to revive some stuff from 40 years ago. Found I could download and install Intel Fortran which seems to be a descendant from an old DEC VMS friend. Even managed to get it 'integrated' into Visual Studio 2022 (somewhat; haven't got a decent help or debug facility running yet... and no idea...

I need to pass the value of a variable from one FORTRAN program to another. The main program carries out calculations with some numerical inputs a,b , I want to enter numerical values of variables in another program like [FONT=arial]real*8 a, b common/variables/a,b a = 1. b = 2. How should I...

Just looking for Fortran compilers. I wrote, compiled and used EM software - a long time ago. Now I'm trying to re-learn Fortran that was so simple, 40+ years ago.

hey everyone. I wrote a code in Fortran to calculate potential values or solve the Laplace equation inside a cube according to the boundary conditions mentioned in the code. this is my code: program laplace_cubic implicit none REAL*8 :: LX, LY, LZ, DELTA, MAX_ERR, ERR INTEGER :: NX, NY...

Hi, I have a piece of Fortran code but I'm not Fortran literate. I'm trying to translate it into Python. I have already made it, but I need someone who can run the Fortran code to compare the values of the variables.

TL;DR Summary: I am beginning research as an undergrad in Physics and have an example file I must analyze for the mean of each column. I cannot use arrays. I need to take the sum of a column of data. Hi all, I am new to fortran and programming in general, but I'm having issues with creating a...

program main ! use ! some library that defines the function to calculate the determinant of a given matrix implicit none real,dimension(2,2)::A real::det_val A(1,1)=1 A(2,2)=1 A(2,1)=0 A(1,2)=0 ! det_val=det(A) print *,det_val ! Should print 1. end program main

Here is the code for example: PROGRAM main CALL B() CALL CaoB(B) contains subroutine B() IMPLICIT NONE write (*,*) 'fk' end subroutine B subroutine CaoB(fcn) implicit none INTERFACE SUBROUTINE fcn() IMPLICIT NONE END SUBROUTINE fcn END INTERFACE write...

program testmatek implicit none integer :: Nc=1000 ,k integer,parameter :: N=2 REAL :: kx ,a0=1.0 ,t0=0.25 DOUBLE PRECISION :: pi=4*ATAN(1.) COMPLEX , PARAMETER :: i=(0,1) complex :: ek1 ,ek2 complex :: MATRIX_ek(N,N) open(1,file='matek.txt') MATRIX_ek(N,N)=(0,0) DO k=-Nc,+Nc...

Even after writing the label , it is showing that label is not defined, please help! my program reads...…... ……... 99 z = b + 2*c*(d - 0.0792079*(e + log((( sqrt(x) + 1.52569)**5.64616)/(((sqrt(x) - 1.26704)**5.93863)*((sqrt(x) - 0.258652)**50.2075)))) - 2 log(x)) zs = g + 2*i*(d - 0.0792079*(e...

Hi, I haven't made a code for it yet, however I will be making a Gauss-Seidel algroithm in Fortran 90, for solving very large matrices (actually to initiate the multi-gird method but that's irrelevant for this). As part of this, I wish to insert matrices into other matrices. in MATLAB this...

I have checked the program several times the program is running but the graphs I am getting is not what I was accepting soon one of the variables approaches zero I don't know why is it happening. The program I have made is below and it's in the FORTRAN language. If anyone knows Fortran can they...

implicit none!do not use an undetermined constant character(len=18)::fname character(len=22)::fname_2 character(len=19)::fname_3 character(len=7)::yyyymmd character(len=1)::dash character(len=1)::d character(len=1)::f1 character(len=1)::f2 character(len=1)::f3 character(len=1)::f4...

Hey guys, I've started to read some OpenMP programming and now I'm trying to parallelize small part of a fortran code. The first thing I would like to do is to parallelize the innermost DO loop. It loops through the number of particles (na) and calculates the distance between some point in 3D...

I want to read values from the ASCII file of GIS by Fortran code. In GIS, an area has meshed. Each mesh has an individual value (e.g. velocity of water). Here is the website that shows how the ASCII file is working in GIS. https://en.wikipedia.org/wiki/Esri_grid I want to know if anybody has...

I have been struggling for over a month now with a problem I cannot fix. I would really appreciate any comment or guidance. Thank you! I am considering an Ising-like model with N agents that han hold one of the following 3 states, represented by vectors: state + : vector (1 0) state 0 : vector...

I am trying to understand OpenMP, but my experiments are not paying off. I made a simple FORTRAN program to show me parallel time results. it turns out that parallel times are greater than single thread. What am I doing wrong? results: (changing number of threads) No OpenMP seconds=...

What is the reason for error while compilation

I tried to calculate the smallest number in my machine with gfortran, g++ and clang. I did it by looping as: a = a / 1.73 In gfortran after 1358 loops, I found that a = 4.9406564584124654E-324, and the value of a never changes from loop 1358 till the end 1500 loop. It is questionable for me...

integer n, ar(12) ar(1) = 1 ar(2) = 2 do n=1, 10 ar(n+2) = ar(n+1) + ar(n) end do do n=0,3 print*, ar(12-3*n) end do print*, ar(ar(ar(4))-1) end

program Lab5A implicit none ! This program introduces Fortran string handling capabilities character*26 upper, lower, name, cap character str*2, one*1 integer from, to, i, m lower = "abcdefghijklmnopqrstuvwxyz" upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"...

<Moderator's note: This thread is a spinoff from https://www.physicsforums.com/threads/need-help-with-fortran-compiler-errors.985749/> There's a lot of Fortran dummies on PF and they know who they are! :-)

Summary:: so I am trying to compile this program and i keep on getting "Unterminated character constant beginning at (1)" and "invalid character in name" at the months section. what do i have to change to fix it? thanks program Lab6 implicit none character*9 month integer monthNum, pos...

I have a simple Fortran code for solving velocity and displacement of spring, the code works fine when writing all together without using a subroutine. but as I am learning Fortran I tried to do it using subroutine, but I keep getting errors appreciate any help in advance. program msd implicit...

Hi, I am a beginner of Fortran. Recently I try to use a fortran code for my simulation. But it always shows me the following error when execute the program: At line 18 of the file sous.f (unit =11, file = 'fluid'), fortran runtime error, End of file, Error termination. Backtrace: could not print...

Hello everybody, I am a master student in Theoretical Chemistry and I am working in the DFT realm. Both TDDFT and DFT applied to extended systems (eg. using QUANTUM ESPRESSO). Of course I work with these softwares from a end-user point of view, not as a developer. But anyway, even if some of...

Does anyone know any FORTRAN didactic tutorial?

Does anyone know a simple implementation in FORTRAN 90 of collisions of particles?

I have tried to do this using arrays and do loops: program matrixmul implicit none real A(2, 2), B (2, 2), C (2, 2) integer i, j, k write (*, *) 'Input: First matrix' do i = 1, 2 do j = 1, 2 read (*, *) A (i, j) enddo enddo write (*, *) 'Input: Second...

Hi All, While trying to read a matrix from data file using fortran90 code ,I get garbage values and a backtrace error. Error termination. Backtrace: #0 0x7f4a4de3631a #1 0x7f4a4de36ec5 #2 0x7f4a4de3768d #3 0x7f4a4dfa4d42 #4 0x7f4a4dfa6ad5 #5 0x7f4a4dfa80f9 #6 0x56040bbeae57 #7...

Say "I have grid in polar coordinates (r, theta). How do I plot it in tecplot. Tecplot plots it in cartesian coordinates."

I'm new to fortran coding and trying to read a file called "data.dat" with data like a triangular matrix 0.1 0.1 0.2 0.1 0.2 0.3 0.1 0.2 0.3 0.4 0.1 0.2 0.3 0.4 0.5 using the code PROGRAM matrix IMPLICIT NONE REAL, DIMENSION(5,5) :: a INTEGER :: row,col,max_rows,max_cols max_rows=5...

Hello. I need help to understand why my code is not giving me double numerical precision. In this piece of code, I create a function that is analytically normalized, but when I calculate the numerical normalization factor, it seems to be with single precision. Here it is: program dyna...

Hi, I am using fortran to read specific columns from a .csv file. the rows in each columns are different, so I wish to read columns wise with a do loop. say, I wish to read from A1 to D20 initially(4 columns of 20 rows), then later f1 to h35 (3 columns, 35 rows). how do I read particular columns...

I'm new to prorgramming . I have been working with Fortran90 for my physics project and I have to read data from a file. I need to find a specific matrix and then print the said matrix onto a different file and diagonalize it. How do I read the matrix that follows a specific line from a file ...

I am calling a fortran 77 subroutine in a fortran 90 code and the results i am getting are wrong as confirmed from matlab. Can anybody please let me know where is the problem? do isss=1,5 do ig=1,10 dat0=dat(:,ig,isss) do iss=1,5 if...

Hi everyone, I am new programming in Fortran and Inhave done about three or four programs that solves different problems in trigonometry, one is the basic one it gives you hypotenuse upon two sides, the other finds the theta angle by giving hypotenuse and opposite side, other find hypotenuse by...

Well, I'm trying to move a bit into modern Fortran, and I am more used to Fortran77 syntax. So, for example, when I wanted to make an array whose two of its components equal another array of another dimension, I used to do something like this: do k=1,N do j=1,N do i=1,N...

I am trying to solve the following first order ODE using a simple Fortran code : $$ ds/dt=k_i * \sqrt{v}$$ where both (ki) and (v) are variables depending on (h) as follows $$ k_i=\sqrt{χ/h^2}$$ $$v= \mu h$$ where (μ) and (χ) are constants. (the arbitrary values of each of them can be seen...

Dear Forum Members, I need to create and use dynamic-link library (DLL) for Fortran application using Compaq Visual Fortran 6.6. The following code works just fine: ########################################### PROGRAM AMAIN1 IMPLICIT NONE REAL(8):: A,B,S A = 1D0 B = 2D0 CALL SUBRO1(A,B,S)...

Hey guys, new here and was hoping for some help. Basically I have to use Fortran 77 to complete some questions for an assignment The first thing to do is, read a bunch of numbers in a list format and then use these numbers to be entered within an equation. The values I have are listed in a 1...

Hello, I am trying to get the parameter MPI_TAG_UB for openmpi (I am using version 2.1.1). I know I need to use the routine MPI_COMM_GET_ATTR, but I have no idea how to do that, I never used fortran in my life. Following this link...

Hello, I need to read a fortran data with complex numbers and real numbers, the first column is the real numbers, the second and third complex numbers (real, imaginary). I need to read the first 64 lines and then the next 64 lines in separate ways and save in a variable. for example read from...

I have a FORTRAN code that is producing no error upon compilation but when I run it, the run aborts with following message "open: illegal unit number apparent state: unit 72 <unnamed> last format: list io lately writing direct formatted external IO This application has requested the Runtime to...

Hey everyone, I’m trying to simulate a 1D Shallow Water wave in FORTRAN using the Lax Wendroff Method. The case is fairly simple. I have a wave generator on one end of a water pool and a wall boundary on another. The waves start traveling towards the wall and are ‘reflected off’ the wall. The...

Hey everyone. I've attached a code I have written in FORTRAN implementing the SOR Method for a 2 D Laplace Equation. Subroutines have been created, grid has been created and initial and BC's applied appropriately. While computing the error of each iteration, I am unable to achieve the desired...

A physics major I'm mentoring has been invited to join a theory group that makes heavy use of FORTRAN in their calculations. The student already knows Python and is adept at using it including integrating diff eqs and solving various challenging 1st year physics type problems. This theory...

Hello, I am writing a program on Fortran to calculate the integral of sin^4(x) between x = 0 and x = π/2. I believe I know how to write the correct code, but I am unsure what the if statement should be for whether or not a point is inside the desired area. Any thoughts? Thanks.

How to use C++ in studying calculus I'm having a hard time.

Homework Statement I've written a program that calculates the discrete Fourier transform of a set of data in FORTRAN 90. To test it, I need to "generate a perfect sine wave of given period, calculate the DFT and write both data and DFT out to file. Plot the result- does it look like what you...