/*
* pi.ino
* Neil Gershenfeld 12/20/20
* pi calculation benchmark
* pi = 3.14159265358979323846
*/

#define NPTS 100000
float a,b,c,pi,dt,mflops;
unsigned long i,tstart,tend;

void setup() {
    Serial.begin(115200);
}

void loop() {
tstart = millis();
a = 0.5;
b = 0.75;
c = 0.25;
pi = 0;
for (i = 1; i <= NPTS; ++i)
pi += a/((i-b)*(i-c));
tend = millis();
dt = (tend-tstart)/1000.0;
mflops = NPTS*5.0/(dt*1e6);
Serial.print("NPTS = ");
Serial.print(NPTS);
Serial.print(" pi = ");
Serial.println(pi);
Serial.print("time = ");
Serial.print(dt);
Serial.print(" estimated MFlops = ");
Serial.println(mflops);
}