Ricker Wavelet application crashes on execution, exit code 255

[Flavio Mesquita]

Hi everyone,
I´m a beginner on programming and Qt, but as liked the framework I´m trying to improve my skills and write my C++ codes on it. I got a task of writting a Ricker wavelet code and then plot it.
I divided it in two tasks, first make the ricker code works, and when it is running, then implement a way to plot it, I will use qcustomplot for it.
I got a code from C and I´m trying to adapt it to Qt. Although it doesn´t give any errors during compilation, when executing it crashes, with the following message:

Invalid parameter passed to C runtime function.
C:/Users/Flavio/Documents/qtTest/build-ricker2-Desktop_Qt_5_11_0_MinGW_32bit-Debug/debug/ricker2.exe exited with code 255

The code I´m supposed to translate is:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
float *rickerwavelet(float fpeak, float dt, int *nwricker);
int main(int argc, char **argv)
{
int i;
float dt;
float fpeak;

float *wricker=NULL;
int nwricker;

fpeak = atof(argv[1]);
dt = atof(argv[2]);

wricker = rickerwavelet(fpeak, dt, &nwricker);

/* show value of ricker wavelets */
for (i=0; i<nwricker; i++)
printf("%i. %3.5f \n", i, wricker[i]);

free(wricker);
return(1);
}

/* ricker wavelet function, return an array ricker wavelets */
float *rickerwavelet(float fpeak, float dt, int *nwricker)
{
int i, k;
int nw;
int nc;
float pi;
float nw1, alpha, beta;
float *wricker=NULL;

pi = 3.141592653589793;
nw1 = 2.2/fpeak/dt;
nw = 2*floor(nw1/2)+1;
nc = floor(nw/2);

wricker = (float*) calloc (nw, sizeof(float));
for (i=0; i<nw; i++)
{
k = i+1;
alpha = (nc-k+1)*fpeak*dt*pi;
beta = pow(alpha, 2.0);
wricker[i] = (1 - (beta*2)) * exp(-beta);
}

(*nwricker) = nw;
return(wricker);
}


The code i wrote on Qt is:

#include <QCoreApplication>
#include <qmath.h>
#include <stdio.h>
#include <stdlib.h>
#include <QDebug>

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
int i,k,nw,nc;
double *wricker=NULL;
int nwricker = 60;
int wavelet_freq = 30;
int polarity=1;
int sampling_rate=0.004;
float nw1, alpha, beta;
const double pi = 3.141592653589793238460;

nw1 = 2.2/wavelet_freq/sampling_rate;
nw = 2*floor(nw1/2)+1;
nc = floor(nw/2);


wricker = (double*)calloc (nw, sizeof(double));
for (i=0; i<nw; i++)
{
k = i+1;
alpha = (nc-k+1)*wavelet_freq*sampling_rate*pi;
beta = pow(alpha, 2.0);
wricker[i] = polarity*((1 - (beta*2)) * exp(-beta));
};
/* show value of ricker wavelets */
for (i=0; i<nwricker; i++)
{
qDebug()<<i<<wricker[i];
};

free(wricker);

return a.exec();
}




Analytic expression

The amplitude A of the Ricker wavelet with peak frequency f at time t is computed like so:

A = (1-2 *pi^2* f^2* t^2) e^{-pi^2* f^2* t^2}

A py code for it would be:


import numpy as np
import matplotlib.pyplot as plt

def ricker(f, length=0.128, dt=0.001):
t = np.arange(-length/2, (length-dt)/2, dt)
y = (1.0 - 2.0*(np.pi**2)*(f**2)*(t**2)) * np.exp(-(np.pi**2)*(f**2)*(t**2))
return t, y

f = 25 # A low wavelength of 25 Hz
t, w = ricker(f)

What seems quite simple.

Does anyone have any idea what is wrong in my code???

Thanks in advance.