xref: /aosp_15_r20/external/musl/src/complex/casin.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include "complex_impl.h"
2*c9945492SAndroid Build Coastguard Worker 
3*c9945492SAndroid Build Coastguard Worker // FIXME
4*c9945492SAndroid Build Coastguard Worker 
5*c9945492SAndroid Build Coastguard Worker /* asin(z) = -i log(i z + sqrt(1 - z*z)) */
6*c9945492SAndroid Build Coastguard Worker 
casin(double complex z)7*c9945492SAndroid Build Coastguard Worker double complex casin(double complex z)
8*c9945492SAndroid Build Coastguard Worker {
9*c9945492SAndroid Build Coastguard Worker 	double complex w;
10*c9945492SAndroid Build Coastguard Worker 	double x, y;
11*c9945492SAndroid Build Coastguard Worker 
12*c9945492SAndroid Build Coastguard Worker 	x = creal(z);
13*c9945492SAndroid Build Coastguard Worker 	y = cimag(z);
14*c9945492SAndroid Build Coastguard Worker 	w = CMPLX(1.0 - (x - y)*(x + y), -2.0*x*y);
15*c9945492SAndroid Build Coastguard Worker 	double complex r = clog(CMPLX(-y, x) + csqrt(w));
16*c9945492SAndroid Build Coastguard Worker 	return CMPLX(cimag(r), -creal(r));
17*c9945492SAndroid Build Coastguard Worker }
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