Slow FFT in ksh93 and awk.


Login or Register for Dates, Times and to Reply

 
Thread Tools Search this Thread
# 15  
Hi Corona688...

Well the Awk DFT has just dropped out of its 14 days viewing on AMINET and has reached 135 downloads.
Did not quite reach the 150 mark, but hey 135 is not bad for such an ancient platform, running the _ADE_ UNIX emulation for the AMIGA A1200; the Awk version for this platform is about 20 years old.

Aminet - dev/gcc/DFT-FFT.awk.txt

From tiny Acorns big trees grow...
There will be someone out there who will improve considerably on this _seed_ that has now been sown.

Thanks a lot matey...
These 2 Users Gave Thanks to wisecracker For This Post:
# 16  
A "small" machine with 4MB RAM isn't so different from the earlier UNIX machines.
# 17  
Quote:
Originally Posted by Corona688
A "small" machine with 4MB RAM isn't so different from the earlier UNIX machines.
Perhaps, but we have come a long way since the inception of the AMIGA A1200.
It is surprising how difficult it is to create code to work on multiple platforms with large time spans between platform types and differences in languages as they evolve over these time spans.
It took me a long time to do an FFT for Python 1.4.0 for the A1200, to the current, (04-10-2018), 3.7.0 for current machines, but I got there in the end. Everything is easy when code is written around current language versions but backwards compatibility is hard.

My next esoteric code is going to be DWTs, (Discrete Wavelet Transforms), and I think it can be done in pure ksh93, and maybe zsh.
It does look fairly straightforward and this site will be the first to have a basic DWT for ksh93 when done.
Once done I will leave the Awk version for you... <wink>
# 18  
Quote:
Originally Posted by wisecracker
It is surprising how difficult it is to create code to work on multiple platforms with large time spans between platform types and differences in languages as they evolve over these time spans.
Depends what you're doing. Hardware I/O changes often, plain old data processing hasn't. awk in particular didn't burden itself with 100,000 obsolete expansion modules like Perl and Python did, or changed as much as shell has; it remains a special-purpose language just for data processing, quite portable. Mostly. You can find it on anything from wireless routers on up, but occasionally we must tell people 'use nawk on solaris' or else they'll get a crusty old version backwards-compatible with 1977.
Quote:
It took me a long time to do an FFT for Python 1.4.0 for the A1200, to the current, (04-10-2018), 3.7.0 for current machines, but I got there in the end. Everything is easy when code is written around current language versions but backwards compatibility is hard.
Python is one of the worst languages for backwards compatibility, its basic syntax changes with every sneeze.
Quote:
Once done I will leave the Awk version for you... <wink>
If you're curious, there's a lot more to learn about awk. It's actually a very fast, powerful, and low-footprint language for processing text. (It had to be, to operate on 1977 hardware.) It's not a do-everything language, it has a few really nice features and not a lot else. You wouldn't write a menu system or graphical UI with it. But for data processing it's almost as powerful as perl.

Last edited by Corona688; 10-04-2018 at 01:50 PM..
These 3 Users Gave Thanks to Corona688 For This Post:
Login or Register for Dates, Times and to Reply

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

10 More Discussions You Might Find Interesting

1. OS X (Apple)

FFT for Python 2.0.x to 3.7.0.

Hi guys... This is code that was originally designed to work on an upgraded AMIGA A1200 using Python 2.0.x. Unfortunately it broke inside much later versions, NOT because of the print statement/function but other minor subtleties. So this is the final result tested on various machines including... (0 Replies)
Discussion started by: wisecracker
0 Replies

2. OS X (Apple)

FFT for the AMIGA through ksh88 shell.

I don't know if anyone is interested but I have been meddling with FFT for the AMIGA. (Sadly we AMIGAns don't have these luxuries through any scripting language. Below is a Python snippet that uses the builtin 'cmath' module to work with the lowly Python 2.0.1 for the AMIGA. It is part of a... (0 Replies)
Discussion started by: wisecracker
0 Replies

3. UNIX for Advanced & Expert Users

Ksh93 on Linux compatible with ksh93 on AIX

Hi Experts, I have several shell scripts that have been developed on a Linux box for korn ksh93. If we want to run this software on an AIX 6.1 box that runs ksh88 by default can we just change the she-bang line to reference /bin/ksh93 which ships with AIX as its "enhanced shell" to ensure... (6 Replies)
Discussion started by: Keith Turley
6 Replies

4. Shell Programming and Scripting

Making a faster alternative to a slow awk command

Hi, I have a large number of input files with two columns of numbers. For example: 83 1453 99 3255 99 8482 99 7372 83 175 I only wish to retain lines where the numbers fullfil two requirements. E.g: =83 1000<=<=2000 To do this I use the following... (10 Replies)
Discussion started by: s052866
10 Replies

5. Shell Programming and Scripting

cut, sed, awk too slow to retrieve line - other options?

Hi, I have a script that, basically, has two input files of this type: file1 key1=value1_1_1 key2=value1_2_1 key4=value1_4_1 ... file2 key2=value2_2_1 key2=value2_2_2 key3=value2_3_1 key4=value2_4_1 ... My files are 10k lines big each (approx). The keys are strings that don't... (7 Replies)
Discussion started by: fzd
7 Replies

6. Shell Programming and Scripting

The builtin split function in AWK is too slow

I have a text file that contains 4 million lines, each line contains 2 fields(colon as field separator). as shown: 123:444,555,666,777,888,345 233:5444,555,666,777,888,345 623:454,585,664,773,888,345 ...... Here I have to split the second field(can be up to 40,000 fields) by comma into an... (14 Replies)
Discussion started by: kevintse
14 Replies

7. Shell Programming and Scripting

Performance degradation with KSH93

Hi, I have a script that calls an external program to perform some calculations and then I read with "grep" and "sed" values from the output files. I've noticed that performance of KSH93 degrades with every iteration. The output files are all the same size, so I don't understand why after the... (2 Replies)
Discussion started by: i.f.schulz
2 Replies

8. Shell Programming and Scripting

ksh88 or ksh93

Hi all! Does anybody know how can I check if any UNIX installation has implemented ksh88 or ksh93? Thanks in advance. NÚstor. (3 Replies)
Discussion started by: Nestor
3 Replies

9. Shell Programming and Scripting

ksh93 deprecation...

Any means of running ksh93 in a ksh88-mode? Might sound odd, but I want/need to restrict U/Win-developed scripts to correspond to the ksh88 version on my Solaris environment(s). Thanks. (2 Replies)
Discussion started by: curleb
2 Replies

10. UNIX for Dummies Questions & Answers

echo is too slow. HELP with Awk

Hello All, Below is a simple script i worte to find the 208th char in a file. If the char = "C" then I re-direct the line to a file called change.txt. If it is not "C" then I re-direct it to a file called delete.txt. My problem is I have a file 0f 500K lines. this script is very slow. I am... (4 Replies)
Discussion started by: eja
4 Replies

Featured Tech Videos