theodorethomas

7 ms·

31.
by theodorethomas 3y ago
It is unsafe if the code was written by a numerical expert who understood the ISO/IEC 60559:2020 standard. Not many of those, so in all probability your garbage code continues to be garbage (but faster) with FMA.
32.
by theodorethomas 5y ago
print *, norm2(x) "The result of NORM2 (X) has a value equal to a processor-dependent approximation to the generalized L2 norm of X, which is the square root of the sum of the squares of the elements of X. If X has size zero, the resul
33.
by theodorethomas 5y ago
Readers, please don't accept anything anyone writes about "FORTRAN", unless in a historical context. They probably last encountered the leading edge of the language 40 years ago.
34.
by theodorethomas 5y ago
Fortran (name since 1990) has SELECT CASE to make Computed GO TO obsolete. Maybe you are thinking of FORTRAN?
35.
by theodorethomas 5y ago
I saw that convention in IBM/NAG's Scratchpad/Axiom computer algebra system which was designed in the 80s. It may go further back than that.
36.
by theodorethomas 5y ago
The "race" was between compilers, GNU compilers in fact, not languages.
37.
by theodorethomas 5y ago
> If you have a `then` clause, you know it will only run when the `if` condition is true. Can someone please tell the clang compiler folks?
38.
by theodorethomas 5y ago
http://www.lahey.com/nl00apr.htm#Fortran_and_the_Space_Progr... describes use of Fortran dummy arrays before Fortran IV. No LDA/B/C in the example provided. But I find it hard to believe that once a compiler exist
39.
by theodorethomas 5y ago
LOC is not Fortran. C_LOC is. "pointer arithmetic" is not Fortran. The Fortran POINTER should not be confused with a C pointer (POINTER has more information). You cannot do arithmetic with a TYPE(C_PTR), either. LDB allows you to
40.
by theodorethomas 5y ago
If you know the language, you will be aware that the word "memory" is not used in the Standard, except in non-normative sections (i.e. Notes), the keyword SYNC MEMORY (whose specification is not about memory but "segments&quo
41.
by theodorethomas 5y ago
We have moved on, from a compiler that could fit in 4kbytes of main memory to one that is a 2Gigabyte download. It was “array slicing” (array expressions) that was missing in F77. That’s what sequence association was meant to help with. You
42.
by theodorethomas 5y ago
I am sitting here looking at a 50-line Fortran routine in our codebase that says ! MARK 1 RELEASE. NAG COPYRIGHT 1971. It has been revised since then to use free form, structured programming, MODULEs, KINDs, INTENTs and IMPLICIT NONE.
43.
by theodorethomas 5y ago
-Building? That’s just bricks, old fashioned. -But we can build with concrete and steel and plastics and all sorts now. -Most people use bricks though. And people are not tearing their brick houses down to rebuild them in steel. See? Buildi
44.
by theodorethomas 5y ago
I am trying to read your statement without concluding that you think that ignorance is a justification for a reputation.
45.
by theodorethomas 5y ago
Fortran is not designed to be a systems programming language and you can tell because it lacks the concept of memory address (hardware has been designed to operate by flipping bits at memory addresses for longer than I can remember). Fortra
46.
by theodorethomas 5y ago
No such thing as modern FORTRAN. It’s been “Fortran” for the last 31 years. People don’t modernize their codes because the Fortran compilers allow them to, and the Standard is reluctant to delete old features (and compilers would not delete
47.
by theodorethomas 5y ago
NAG Fortran Compiler 7.0 fully supports F2003 and partially supports F2008 and F2018. I should know! https://www.nag.com/content/nag-fortran-compiler
48.
by theodorethomas 5y ago
<as long as they are required to preface every module and program with `implicit none`> A small price to pay for being able to run code from 60 years ago. And no, there is no such requirement as such. <need to specify the "lea