You have some lengths 12 in the constructor, so it may be better to use length 12. Also, use instead character(len=12), dimension(5) :: models = [character(len=12) :: “feddes.swp”, & “jarvis89.swp”, “jarvis10.swp”, “pem.swp”, “van.swp”] Possibly even better, if you have compiler support, is character(len=*), dimension(*) :: …
Bare minimum -Og/-O0 -O0 basically tells the compiler to make no optimisations. Optimiser can remove some local variables, merge some code blocks, etc. and as an outcome it can make debugging unpredictable. The price for -O0 option is very slow code execution, but starting from version 4.8 GCC compilers (including the Fortran one) accept a … Read more
What you care about here is association: you want to be able to associate entities in the function f with those in the subroutine condat. Storage association is one way to do this, which is what the common block is doing. There are other forms of association which can be useful. These are use association … Read more
There is no built-in “big number” support, but we can first check whether there is a larger integer kind available (as mentioned by Francescalus above and also many previous pages (e.g. this page). On my computer with gfortran-6.1, the compiler seems to support 128-bit integer kind, so I could calculate the result up to n=160 … Read more
This is an arithmetic if statement from FORTRAN 77. Adapted from the FORTRAN 77 specification (emphasis mine): The form of an arithmetic IF statement is: IF (e) s1 , s2 , s2 where: e is an integer, real, or double precision expression s1, s2, and s3 are each the statement label of an executable statement … Read more
You don’t need anonymous functions for this. Your Matlab example is also not anonymous in the end, it has a name g. Fortran internal functions are of great use here (Fortran 2008 feature, but supported in gfortran and ifort, not supported in Solaris Studio): call minimum(g, x0, xopt) contains real function g(x) real, intent(in) :: … Read more
The random number generator produces pseudo-random numbers. To get different numbers each run, you need to initialise the random seed at the start of your program. This picks a different starting position in the pseudo-random stream.
The 8 refers to the number of bytes that the data type uses. So a 32-bit integer is integer*4 along the same lines. A quick search found this guide to Fortran data types, which includes: The “real*4” statement specifies the variable names to be single precision 4-byte real numbers which has 7 digits of accuracy … Read more
Wow … I haven’t seen that syntax in a while. That is a Fortran Arithmetic IF Statement. The result of KODE(J) is a number. If it is less than zero, then the first jump is used, if it is equal to zero, then the second jump is used, otherwise, the third jump is used. This … Read more
I fear that you will not be able to do this. Fortran requires that variables have names and types at compile time. You (or other SOers) may come up with some kludge to simulate what you want, but it will be a kludge. Why do you want to do this in Fortran ? There are … Read more