If I had an array of numbers such as [3, 5, 0, 8, 4, 2, 6], is there a way to “smooth out” the values so they’re closer to each other and display less variance?

I’ve looked into windowing the data using something called the Gaussian function for a 1-dimensional case, which is my array, but am having trouble implementing it. This thread seems to solve exactly what I need but I don’t understand how user naschilling (second post) came up with the Gaussian matrix values.

Context: I’m working on a music waveform generator (borrowing from SoundCloud’s design) that maps the amplitude of the song at time t to a corresponding bar height. Unfortunately there’s a lot of noise, and it looks particularly ugly when the program maps a tiny amplitude which results in a sudden decrease in height. You can see what it looks like here. I basically want to smooth out the bar heights so they aren’t so varied.

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If I had an array of numbers such as [3, 5, 0, 8, 4, 2, 6], is there a way to “smooth out” the values so they’re closer to each other and display less variance?

I’ve looked into windowing the data using something called the Gaussian function for a 1-dimensional case, which is my array, but am having trouble implementing it. This thread seems to solve exactly what I need but I don’t understand how user naschilling (second post) came up with the Gaussian matrix values.

Context: I’m working on a music waveform generator (borrowing from SoundCloud’s design) that maps the amplitude of the song at time t to a corresponding bar height. Unfortunately there’s a lot of noise, and it looks particularly ugly when the program maps a tiny amplitude which results in a sudden decrease in height. You can see what it looks like here. I basically want to smooth out the bar heights so they aren’t so varied.

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I have a command run using exec() which returns a value from within a very large data file, but it has to run millions of times. In order to avoid having the file opened each time in a loop, I want to move to a proc_open-based solution, where the file pointer is created once for efficiency, but can’t work out how to do this.

Here is the exec-based version, which works but is slow, presumably because it has to open the file in each iteration:

foreach ($locations as $location) {
    $command = "gdallocationinfo -valonly -wgs84 datafile.img {$location['lon']} {$location['lat']}";
    echo exec ($command);
}

My attempt at a proc_open-based code is as follows:

$descriptorspec = array (
    0 => array ('pipe', 'r'),  // stdin - pipe that the child will read from
    1 => array ('pipe', 'w'),  // stdout - pipe that the child will write to
    // 2 => array ('file', '/tmp/errors.txt', 'a'), // stderr - file to write to
);

$command = "gdallocationinfo -valonly -wgs84 datafile.img";
$fp = proc_open ($command, $descriptorspec, $pipes);

foreach ($locations as $location) {
    fwrite ($pipes[0], "{$location['lon']} {$location['lat']}\n");
    fclose ($pipes[0]);
    echo stream_get_contents ($pipes[1]);
    fclose ($pipes[1]);
}

proc_close ($fp);

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I have a command run using exec() which returns a value from within a very large data file, but it has to run millions of times. In order to avoid having the file opened each time in a loop, I want to move to a proc_open-based solution, where the file pointer is created once for efficiency, but can’t work out how to do this.

Here is the exec-based version, which works but is slow, presumably because it has to open the file in each iteration:

foreach ($locations as $location) {
    $command = "gdallocationinfo -valonly -wgs84 datafile.img {$location['lon']} {$location['lat']}";
    echo exec ($command);
}

My attempt at a proc_open-based code is as follows:

$descriptorspec = array (
    0 => array ('pipe', 'r'),  // stdin - pipe that the child will read from
    1 => array ('pipe', 'w'),  // stdout - pipe that the child will write to
    // 2 => array ('file', '/tmp/errors.txt', 'a'), // stderr - file to write to
);

$command = "gdallocationinfo -valonly -wgs84 datafile.img";
$fp = proc_open ($command, $descriptorspec, $pipes);

foreach ($locations as $location) {
    fwrite ($pipes[0], "{$location['lon']} {$location['lat']}\n");
    fclose ($pipes[0]);
    echo stream_get_contents ($pipes[1]);
    fclose ($pipes[1]);
}

proc_close ($fp);

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