/**********
Copyright 1990 Regents of the University of California.  All rights reserved.
Author: 1989 Jaijeet S. Roychowdhury
**********/

#include "spice.h"
#include "distodef.h"
#include "suffix.h"

/*
 * AtanDeriv computes the partial derivatives of the arctangent
 * function where the argument to the atan function is itself a
 * function of three variables p, q, and r.
 */

void AtanDeriv(new, old)
Dderivs *new, *old;
{

Dderivs temp;

EqualDeriv(&temp, old);

new->value = atan( temp.value);
new->d1_p = temp.d1_p/(1+temp.value*temp.value);
new->d1_q = temp.d1_q/(1+temp.value*temp.value);
new->d1_r = temp.d1_r/(1+temp.value*temp.value);
new->d2_p2 = temp.d2_p2/(1+temp.value*temp.value) - 2*temp.value*new->d1_p*new->d1_p;
new->d2_q2 = temp.d2_q2/(1+temp.value*temp.value) - 2*temp.value*new->d1_q*new->d1_q;
new->d2_r2 = temp.d2_r2/(1+temp.value*temp.value) - 2*temp.value*new->d1_r*new->d1_r;
new->d2_pq = temp.d2_pq/(1+temp.value*temp.value) - 2*temp.value*new->d1_p*new->d1_q;
new->d2_qr = temp.d2_qr/(1+temp.value*temp.value) - 2*temp.value*new->d1_q*new->d1_r;
new->d2_pr = temp.d2_pr/(1+temp.value*temp.value) - 2*temp.value*new->d1_p*new->d1_r;
new->d3_p3 = (temp.d3_p3 - temp.d2_p2*new->d1_p*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_p*new->d1_p*temp.d1_p + temp.value*(
		new->d2_p2*new->d1_p + new->d2_p2*new->d1_p));
new->d3_q3 = (temp.d3_q3 - temp.d2_q2*new->d1_q*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_q*new->d1_q*temp.d1_q + temp.value*(
		new->d2_q2*new->d1_q + new->d2_q2*new->d1_q));
new->d3_r3 = (temp.d3_r3 - temp.d2_r2*new->d1_r*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_r*new->d1_r*temp.d1_r + temp.value*(
		new->d2_r2*new->d1_r + new->d2_r2*new->d1_r));
new->d3_p2r = (temp.d3_p2r - temp.d2_p2*new->d1_r*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_p*new->d1_p*temp.d1_r + temp.value*(
		new->d2_pr*new->d1_p + new->d2_pr*new->d1_p));
new->d3_p2q = (temp.d3_p2q - temp.d2_p2*new->d1_q*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_p*new->d1_p*temp.d1_q + temp.value*(
		new->d2_pq*new->d1_p + new->d2_pq*new->d1_p));
new->d3_q2r = (temp.d3_q2r - temp.d2_q2*new->d1_r*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_q*new->d1_q*temp.d1_r + temp.value*(
		new->d2_qr*new->d1_q + new->d2_qr*new->d1_q));
new->d3_pq2 = (temp.d3_pq2 - temp.d2_q2*new->d1_p*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_q*new->d1_q*temp.d1_p + temp.value*(
		new->d2_pq*new->d1_q + new->d2_pq*new->d1_q));
new->d3_pr2 = (temp.d3_pr2 - temp.d2_r2*new->d1_p*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_r*new->d1_r*temp.d1_p + temp.value*(
		new->d2_pr*new->d1_r + new->d2_pr*new->d1_r));
new->d3_qr2 = (temp.d3_qr2 - temp.d2_r2*new->d1_q*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_r*new->d1_r*temp.d1_q + temp.value*(
		new->d2_qr*new->d1_r + new->d2_qr*new->d1_r));
new->d3_pqr = (temp.d3_pqr - temp.d2_pq*new->d1_r*2*temp.value)
		/(1+temp.value*temp.value) - 2*(new->d1_p*new->d1_q*temp.d1_r + temp.value*(
		new->d2_pr*new->d1_q + new->d2_qr*new->d1_p));
		}
