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#include "rb_lapack.h"
extern VOID zlaev2_(doublecomplex* a, doublecomplex* b, doublecomplex* c, doublereal* rt1, doublereal* rt2, doublereal* cs1, doublecomplex* sn1);
static VALUE
rblapack_zlaev2(int argc, VALUE *argv, VALUE self){
VALUE rblapack_a;
doublecomplex a;
VALUE rblapack_b;
doublecomplex b;
VALUE rblapack_c;
doublecomplex c;
VALUE rblapack_rt1;
doublereal rt1;
VALUE rblapack_rt2;
doublereal rt2;
VALUE rblapack_cs1;
doublereal cs1;
VALUE rblapack_sn1;
doublecomplex sn1;
VALUE rblapack_options;
if (argc > 0 && TYPE(argv[argc-1]) == T_HASH) {
argc--;
rblapack_options = argv[argc];
if (rb_hash_aref(rblapack_options, sHelp) == Qtrue) {
printf("%s\n", "USAGE:\n rt1, rt2, cs1, sn1 = NumRu::Lapack.zlaev2( a, b, c, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n SUBROUTINE ZLAEV2( A, B, C, RT1, RT2, CS1, SN1 )\n\n* Purpose\n* =======\n*\n* ZLAEV2 computes the eigendecomposition of a 2-by-2 Hermitian matrix\n* [ A B ]\n* [ CONJG(B) C ].\n* On return, RT1 is the eigenvalue of larger absolute value, RT2 is the\n* eigenvalue of smaller absolute value, and (CS1,SN1) is the unit right\n* eigenvector for RT1, giving the decomposition\n*\n* [ CS1 CONJG(SN1) ] [ A B ] [ CS1 -CONJG(SN1) ] = [ RT1 0 ]\n* [-SN1 CS1 ] [ CONJG(B) C ] [ SN1 CS1 ] [ 0 RT2 ].\n*\n\n* Arguments\n* =========\n*\n* A (input) COMPLEX*16\n* The (1,1) element of the 2-by-2 matrix.\n*\n* B (input) COMPLEX*16\n* The (1,2) element and the conjugate of the (2,1) element of\n* the 2-by-2 matrix.\n*\n* C (input) COMPLEX*16\n* The (2,2) element of the 2-by-2 matrix.\n*\n* RT1 (output) DOUBLE PRECISION\n* The eigenvalue of larger absolute value.\n*\n* RT2 (output) DOUBLE PRECISION\n* The eigenvalue of smaller absolute value.\n*\n* CS1 (output) DOUBLE PRECISION\n* SN1 (output) COMPLEX*16\n* The vector (CS1, SN1) is a unit right eigenvector for RT1.\n*\n\n* Further Details\n* ===============\n*\n* RT1 is accurate to a few ulps barring over/underflow.\n*\n* RT2 may be inaccurate if there is massive cancellation in the\n* determinant A*C-B*B; higher precision or correctly rounded or\n* correctly truncated arithmetic would be needed to compute RT2\n* accurately in all cases.\n*\n* CS1 and SN1 are accurate to a few ulps barring over/underflow.\n*\n* Overflow is possible only if RT1 is within a factor of 5 of overflow.\n* Underflow is harmless if the input data is 0 or exceeds\n* underflow_threshold / macheps.\n*\n* =====================================================================\n*\n\n");
return Qnil;
}
if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
printf("%s\n", "USAGE:\n rt1, rt2, cs1, sn1 = NumRu::Lapack.zlaev2( a, b, c, [:usage => usage, :help => help])\n");
return Qnil;
}
} else
rblapack_options = Qnil;
if (argc != 3 && argc != 3)
rb_raise(rb_eArgError,"wrong number of arguments (%d for 3)", argc);
rblapack_a = argv[0];
rblapack_b = argv[1];
rblapack_c = argv[2];
if (argc == 3) {
} else if (rblapack_options != Qnil) {
} else {
}
a.r = NUM2DBL(rb_funcall(rblapack_a, rb_intern("real"), 0));
a.i = NUM2DBL(rb_funcall(rblapack_a, rb_intern("imag"), 0));
c.r = NUM2DBL(rb_funcall(rblapack_c, rb_intern("real"), 0));
c.i = NUM2DBL(rb_funcall(rblapack_c, rb_intern("imag"), 0));
b.r = NUM2DBL(rb_funcall(rblapack_b, rb_intern("real"), 0));
b.i = NUM2DBL(rb_funcall(rblapack_b, rb_intern("imag"), 0));
zlaev2_(&a, &b, &c, &rt1, &rt2, &cs1, &sn1);
rblapack_rt1 = rb_float_new((double)rt1);
rblapack_rt2 = rb_float_new((double)rt2);
rblapack_cs1 = rb_float_new((double)cs1);
rblapack_sn1 = rb_funcall(rb_gv_get("Complex"), rb_intern("new"), 2, rb_float_new((double)(sn1.r)), rb_float_new((double)(sn1.i)));
return rb_ary_new3(4, rblapack_rt1, rblapack_rt2, rblapack_cs1, rblapack_sn1);
}
void
init_lapack_zlaev2(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
sHelp = sH;
sUsage = sU;
rblapack_ZERO = zero;
rb_define_module_function(mLapack, "zlaev2", rblapack_zlaev2, -1);
}
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