Source Code for Trigamma Function in C

[Alamino]

Trigamma Function in C

Does anyone know where can I find the source code for calculating numerically the trigamma function? Or does anyone know the source code itself?

Thanks.

 

[nbo10]

You might be able to find some code on the net. The standard package used is imsl, but it costs a few bucks to use.

JMD

 

[ravenprp]

Here is a simple implementation of the trigamma function in C:

#include <math.h>

double trigamma(double x) {
double result = 0.0;
double n = 1.0;
double term = 0.0;
double epsilon = 1e-8; // desired accuracy

while (fabs(term) >= epsilon) {
term = 1 / (x + n) / (x + n);
result += term;
n++;
}
return result;
}

int main() {
double x = 1.5; // input value
double result = trigamma(x);
printf("The trigamma function of %.2f is %.6f\n", x, result);
return 0;
}

This code uses a while loop to iteratively calculate the sum of terms in the trigamma function until the desired accuracy is reached. It also includes a simple test case in the main function to demonstrate its usage. Keep in mind that this is just one possible implementation and there may be more efficient or accurate ways to calculate the trigamma function.