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#include "rb_lapack.h"
extern VOID slasv2_(real* f, real* g, real* h, real* ssmin, real* ssmax, real* snr, real* csr, real* snl, real* csl);
static VALUE
rblapack_slasv2(int argc, VALUE *argv, VALUE self){
VALUE rblapack_f;
real f;
VALUE rblapack_g;
real g;
VALUE rblapack_h;
real h;
VALUE rblapack_ssmin;
real ssmin;
VALUE rblapack_ssmax;
real ssmax;
VALUE rblapack_snr;
real snr;
VALUE rblapack_csr;
real csr;
VALUE rblapack_snl;
real snl;
VALUE rblapack_csl;
real csl;
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 ssmin, ssmax, snr, csr, snl, csl = NumRu::Lapack.slasv2( f, g, h, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n SUBROUTINE SLASV2( F, G, H, SSMIN, SSMAX, SNR, CSR, SNL, CSL )\n\n* Purpose\n* =======\n*\n* SLASV2 computes the singular value decomposition of a 2-by-2\n* triangular matrix\n* [ F G ]\n* [ 0 H ].\n* On return, abs(SSMAX) is the larger singular value, abs(SSMIN) is the\n* smaller singular value, and (CSL,SNL) and (CSR,SNR) are the left and\n* right singular vectors for abs(SSMAX), giving the decomposition\n*\n* [ CSL SNL ] [ F G ] [ CSR -SNR ] = [ SSMAX 0 ]\n* [-SNL CSL ] [ 0 H ] [ SNR CSR ] [ 0 SSMIN ].\n*\n\n* Arguments\n* =========\n*\n* F (input) REAL\n* The (1,1) element of the 2-by-2 matrix.\n*\n* G (input) REAL\n* The (1,2) element of the 2-by-2 matrix.\n*\n* H (input) REAL\n* The (2,2) element of the 2-by-2 matrix.\n*\n* SSMIN (output) REAL\n* abs(SSMIN) is the smaller singular value.\n*\n* SSMAX (output) REAL\n* abs(SSMAX) is the larger singular value.\n*\n* SNL (output) REAL\n* CSL (output) REAL\n* The vector (CSL, SNL) is a unit left singular vector for the\n* singular value abs(SSMAX).\n*\n* SNR (output) REAL\n* CSR (output) REAL\n* The vector (CSR, SNR) is a unit right singular vector for the\n* singular value abs(SSMAX).\n*\n\n* Further Details\n* ===============\n*\n* Any input parameter may be aliased with any output parameter.\n*\n* Barring over/underflow and assuming a guard digit in subtraction, all\n* output quantities are correct to within a few units in the last\n* place (ulps).\n*\n* In IEEE arithmetic, the code works correctly if one matrix element is\n* infinite.\n*\n* Overflow will not occur unless the largest singular value itself\n* overflows or is within a few ulps of overflow. (On machines with\n* partial overflow, like the Cray, overflow may occur if the largest\n* singular value is within a factor of 2 of overflow.)\n*\n* Underflow is harmless if underflow is gradual. Otherwise, results\n* may correspond to a matrix modified by perturbations of size near\n* the underflow threshold.\n*\n* =====================================================================\n*\n\n");
return Qnil;
}
if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
printf("%s\n", "USAGE:\n ssmin, ssmax, snr, csr, snl, csl = NumRu::Lapack.slasv2( f, g, h, [: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_f = argv[0];
rblapack_g = argv[1];
rblapack_h = argv[2];
if (argc == 3) {
} else if (rblapack_options != Qnil) {
} else {
}
f = (real)NUM2DBL(rblapack_f);
h = (real)NUM2DBL(rblapack_h);
g = (real)NUM2DBL(rblapack_g);
slasv2_(&f, &g, &h, &ssmin, &ssmax, &snr, &csr, &snl, &csl);
rblapack_ssmin = rb_float_new((double)ssmin);
rblapack_ssmax = rb_float_new((double)ssmax);
rblapack_snr = rb_float_new((double)snr);
rblapack_csr = rb_float_new((double)csr);
rblapack_snl = rb_float_new((double)snl);
rblapack_csl = rb_float_new((double)csl);
return rb_ary_new3(6, rblapack_ssmin, rblapack_ssmax, rblapack_snr, rblapack_csr, rblapack_snl, rblapack_csl);
}
void
init_lapack_slasv2(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
sHelp = sH;
sUsage = sU;
rblapack_ZERO = zero;
rb_define_module_function(mLapack, "slasv2", rblapack_slasv2, -1);
}
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