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#include "rb_lapack.h"
extern VOID dlartgs_(doublereal* x, doublereal* y, doublereal* sigma, doublereal* cs, doublereal* sn);
static VALUE
rblapack_dlartgs(int argc, VALUE *argv, VALUE self){
VALUE rblapack_x;
doublereal x;
VALUE rblapack_y;
doublereal y;
VALUE rblapack_sigma;
doublereal sigma;
VALUE rblapack_cs;
doublereal cs;
VALUE rblapack_sn;
doublereal sn;
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 cs, sn = NumRu::Lapack.dlartgs( x, y, sigma, [:usage => usage, :help => help])\n\n\nFORTRAN MANUAL\n SUBROUTINE DLARTGS( X, Y, SIGMA, CS, SN )\n\n* Purpose\n* =======\n*\n* DLARTGS generates a plane rotation designed to introduce a bulge in\n* Golub-Reinsch-style implicit QR iteration for the bidiagonal SVD\n* problem. X and Y are the top-row entries, and SIGMA is the shift.\n* The computed CS and SN define a plane rotation satisfying\n*\n* [ CS SN ] . [ X^2 - SIGMA ] = [ R ],\n* [ -SN CS ] [ X * Y ] [ 0 ]\n*\n* with R nonnegative. If X^2 - SIGMA and X * Y are 0, then the\n* rotation is by PI/2.\n*\n\n* Arguments\n* =========\n*\n* X (input) DOUBLE PRECISION\n* The (1,1) entry of an upper bidiagonal matrix.\n*\n* Y (input) DOUBLE PRECISION\n* The (1,2) entry of an upper bidiagonal matrix.\n*\n* SIGMA (input) DOUBLE PRECISION\n* The shift.\n*\n* CS (output) DOUBLE PRECISION\n* The cosine of the rotation.\n*\n* SN (output) DOUBLE PRECISION\n* The sine of the rotation.\n*\n\n* ===================================================================\n*\n\n");
return Qnil;
}
if (rb_hash_aref(rblapack_options, sUsage) == Qtrue) {
printf("%s\n", "USAGE:\n cs, sn = NumRu::Lapack.dlartgs( x, y, sigma, [: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_x = argv[0];
rblapack_y = argv[1];
rblapack_sigma = argv[2];
if (argc == 3) {
} else if (rblapack_options != Qnil) {
} else {
}
x = NUM2DBL(rblapack_x);
sigma = NUM2DBL(rblapack_sigma);
y = NUM2DBL(rblapack_y);
dlartgs_(&x, &y, &sigma, &cs, &sn);
rblapack_cs = rb_float_new((double)cs);
rblapack_sn = rb_float_new((double)sn);
return rb_ary_new3(2, rblapack_cs, rblapack_sn);
}
void
init_lapack_dlartgs(VALUE mLapack, VALUE sH, VALUE sU, VALUE zero){
sHelp = sH;
sUsage = sU;
rblapack_ZERO = zero;
rb_define_module_function(mLapack, "dlartgs", rblapack_dlartgs, -1);
}
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