writing log files issue

anna

Hi,

I am running an experiment containing multiple trials.

Data for each trial are logged to a text file (using log() from WriteFile) inside of render().

What is the best approach for creating and closing a separate for each trial?

Currently the files are not closing between trials. We identified the WriteFile::writeAllData() function but it does not appear to write and close the file properly.

I have pasted a minimal example of our current solution below:

WriteFile file1;

void loop(void*) {
// This is the auxilary task function which will read our Trill sensors
// loop
while(!Bela_stopRequested())
{
                 // newtrial is a variable set to 1 based on user input (code not shown here).
          if(newtrial){
file1.setup("out.bin"); //set the file name to write to
file1.setEchoInterval(10000); // only print to the console every 10000 calls to log
file1.setFileType(kBinary);
// set the format that you want to use for your output.
// Please use %f only (with modifiers).
// When in binary mode, this is used only for echoing to console
file1.setFormat("binary: %.4f %.4f %.4f %.4f\n")
      }
}

bool setup(BelaContext *context, void *userData)
{

}
void render(BelaContext *context, void *userData)
{
static int count = 0;
for(unsigned int n = 0; n < context->analogFrames; ++n) {


            file1.log(somedata); // log an array of values: the first 4 channels from analog input
    }
   
    count += context->analogFrames;
}
void cleanup(BelaContext *context, void *userData)
{
}

Thanks in advance,
Annna

giuliomoro

anna What is the best approach for creating and closing a separate for each trial?

Create and destroy a new object for each file, e.g.: make file1 a pointer and call new / delete on it. If you can tolerate a dropout in the audio thread while changing file, it is pretty straightforward to do it from the audio thread. Otherwise, you'll need to do it from the auxiliary task and implement some mutual exclusion mechanism to ensure the audio thread doesn't try to access the pointer while the object is being destroyed / created.

anna

Thanks! Is it possible to provide a (simple) code example? I am not skilled with memory allocation, so an example would be very appreciated.

giuliomoro

what I would do is get rid of the loop() task and do everything from render().

something like this:

#include <Bela.h>
#include <libraries/WriteFile/WriteFile.h>

WriteFile* file1 = nullptr;

bool setup(BelaContext *context, void *userData)
{
    newTrial = true;
    return true;
}

void render(BelaContext *context, void *userData)
{
    // newtrial is a variable set to 1 based on user input (code not shown here).
    if(newtrial){
        newtrial = 0;
        delete file1;
        file1 = new WriteFile;
        file1->setup("out.bin"); //set the file name to write to
        file1->setEchoInterval(10000); // only print to the console every 10000 calls to log
        file1->setFileType(kBinary);
        // set the format that you want to use for your output.
        // Please use %f only (with modifiers).
        // When in binary mode, this is used only for echoing to console
        file1->setFormat("binary: %.4f %.4f %.4f %.4f\n")
    }

    for(unsigned int n = 0; n < context->analogFrames; ++n) {
            file1->log(somedata); // log an array of values: the first 4 channels from analog input
    }   
}

void cleanup(BelaContext *context, void *userData)
{
   // remember to delete the pointer here so that the last file is properly saved and closed.
    delete file1;
}