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Programming Leftovers

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  • abs function in C

    Why is it necessary for programmers to use the abs() function? It’s accessible in almost every programming language; But how much good is a function that just turns negative values into positive ones? You may find yourself wanting positive numbers occasionally, and the abs() function ensures that you will get them. The abs function is an abbreviation for “Absolute Value” inside the C programming language, and it specifies the distance of a number just on a number line beginning from 0 without taking the direction into account. The abs value of a number, or its absolute value, has always been positive, implying that a distance could never be negative.
    The abs () method returns the absolute appropriate value integers and is specified in the stdlib.h header file. To return the absolute value of a particular number, we must include the stdlib.h header file in our C application. Only positive values are returned by the abs() function.

    Consider the following scenario: If we have an integer number -2 and wish to find the absolute value, we may use the abs() method to have the positive number 2. In addition, when we have an integer number 2 and want to determine the absolute value, we can use the abs() method to return the very same value as 2. It gives the very same number if we provide it with any positive number.

  • Printf-style debugging using GDB, Part 2

    The first article in this series introduced the GNU debugger, GDB, and in particular its dprintf command, which displays variables from programs in a fashion similar to C-language printf statements. This article expands on the rich capabilities of printf-style debugging by showing how to save commands for reuse and how to save the output from the program and GDB for later examination.

  • Python Wrapper to find all primes from a given interval via sieve of Eratosthenes released as C++ procedure
  • Intel Contributes AVX-512 Optimizations To Numpy, Yields Massive Speedups - Phoronix

    Intel has contributed AVX-512 optimizations to upstream Numpy. For those using Numpy as this leading Python library for numerical computing, newer Intel CPUs with AVX-512 capabilities can enjoy major speed-ups in the range of 14~32x faster.

    This summer Intel volleyed their initial AVX-512 code for Numpy and finally this week the code was merged upstream. This open-source AVX-512 code originates from the Intel Short Vector Math Library (SVML) that they open-sourced the code from. Intel has also been working on allowing Numpy to be built against SVML as a separate improvement.

  • TSV to CSV on the CLI (if you really have to)

    Regular visitors to this blog will know that I don't like the CSV format. It's awful. In my humble opinion, data workers should aim to use invisible tabs (TSV) or visible pipes (PSV) as field separators in delimited text tables. Sometimes, though, data workers are required to convert a perfectly good TSV or PSV to a CSV. What to do?

    I don't recommend opening the TSV or PSV in spreadsheet software and saving the result as a CSV, unless there are no leading or trailing quotes in the data items, or umatched quotes generally. The original quotes might well disappear in the saved CSV.

    There are a number of TSV-to-CSV programs for the command line. One is in Haskell, for example, and there also routines to do the job in Perl and Python. But if the individual fields in the TSV don't contain commas or quotes, the TSV-to-CSV conversion is simple — use tr:

  • Useful Bash Commands You May Not Know About

    Bash is a fairly powerful language to program in, and is also quite easy to start off with.

    After all, it's almost universally the shell you're going to see when you open up your terminal. That makes it extremely useful to get accustomed to.

    There's some powerful commands in Bash that you may not be aware of though, even if you're fairly seasoned with using the language. All of these commands can serve quite useful purposes though, and can make the shell scripts you write cleaner, more maintainable, and just outright more powerful than they could've been before.