LCC equations parameters in the code

[skateskate]

Hello,
first of all thank you very much for your project, it sounds amazing!
I am trying to understand the code of the lcc() function in order to find a one-to-one correspondence with the LCC equations written in one of your papers. Unfortunately, there are some parameters that I cannot link back to the equations.
For clarity, here is the code of the lcc() function and the equations I am referring to.

static void lcc(){
	for (int i=0; i<buflen; i += 2) {
		in_LR[i]   = in_LR[i]   * inputgain;
		in_LR[i+1] = in_LR[i+1] * inputgain;
		
		out_LR[i]   = in_LR[i]   - decaygain * prevOut_LR[i+1]; //Left channel
		out_LR[i+1] = in_LR[i+1] - decaygain * prevOut_LR[i]; //Right channel

		if (i==0) {
			prevOut_LR[buflen-2] += out_LR[0]*delaymod;
			prevOut_LR[buflen-1] += out_LR[1]*delaymod;
		}
	}	
	
	for (int i=0; i<buflen; i += 2){
		if (i<buflen-2) {
			prevOut_LR[i]   = out_LR[i]*delaymodinv  + out_LR[i+2]*delaymod;
			prevOut_LR[i+1] = out_LR[i+1]*delaymodinv + out_LR[i+3]*delaymod;
		} else {
			prevOut_LR[i]   = out_LR[i]*delaymodinv;
			prevOut_LR[i+1] = out_LR[i+1]*delaymodinv;
		}
		out_LR[i] = endgain*(out_LR[i]     + in_LR[i]*centergain*inputgain/2 +
			in_LR[i+1]*centergain*inputgain/2);
		out_LR[i+1] = endgain*(out_LR[i+1] + in_LR[i]*centergain*inputgain/2 +
			in_LR[i+1]*centergain*inputgain/2);
	}
}

The used parameters are:

• inputgain: scales the input samples. Not directly present in the equations, but it is ok to me, since it should be compensated by endgain if I am not wrong.
• decaygain: it should be the "alpha" parameter in the equations, right?
• delaymod: unfortunately I cannot understand the meaning of this parameter, nor I can find the corresponding element in the equations.
• delaymodinv: same as the previous parameter.
• centergain: if I am not wrong, it should be the "beta" parameter in the equations.

I am not sure also on the d term of the equation (the "forward interval delay per reiteration"), where is it used in the code?

Sorry for the multiple questions... :)