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Functions
FLA_Bsvd_ext.c File Reference

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Functions

FLA_Error FLA_Bsvd_ext (FLA_Uplo uplo, FLA_Obj d, FLA_Obj e, FLA_Obj G, FLA_Obj H, FLA_Svd_type jobu, FLA_Obj U, FLA_Svd_type jobv, FLA_Obj V, FLA_Bool apply_Uh2C, FLA_Obj C)
 

Function Documentation

◆ FLA_Bsvd_ext()

FLA_Error FLA_Bsvd_ext ( FLA_Uplo  uplo,
FLA_Obj  d,
FLA_Obj  e,
FLA_Obj  G,
FLA_Obj  H,
FLA_Svd_type  jobu,
FLA_Obj  U,
FLA_Svd_type  jobv,
FLA_Obj  V,
FLA_Bool  apply_Uh2C,
FLA_Obj  C 
)

References FLA_Bsvd_ext_check(), FLA_Bsvd_ext_opt_var1(), FLA_Check_error_level(), FLA_Obj_vector_dim(), and FLA_Part_1x2().

18 {
19  FLA_Error r_val = FLA_SUCCESS;
20  dim_t n_iter_max = 30;
21  dim_t b_alg = 512;
22  dim_t m_d = FLA_Obj_vector_dim( d );
23  FLA_Obj W;
24 
25  // Check parameters.
26  if ( FLA_Check_error_level() >= FLA_MIN_ERROR_CHECKING )
27  FLA_Bsvd_ext_check( uplo, d, e, G, H, jobu, U, jobv, V, apply_Uh2C, C );
28 
29  // Partition U and V properly to account for the diagonal dimension.
30  if ( jobu == FLA_SVD_VECTORS_MIN_COPY ||
31  jobu == FLA_SVD_VECTORS_MIN_OVERWRITE )
32  FLA_Part_1x2( U, &U, &W, m_d, FLA_LEFT );
33 
34  if ( jobv == FLA_SVD_VECTORS_MIN_COPY ||
35  jobv == FLA_SVD_VECTORS_MIN_OVERWRITE )
36  FLA_Part_1x2( V, &V, &W, m_d, FLA_LEFT );
37 
38  // when uplo is lower triangular, swap U and V.
39  if ( uplo == FLA_LOWER_TRIANGULAR )
40  exchange( U, V, W );
41 
42  // [ U1 d e V1 ] = Bidiag( A );
43  // [ U2 d V2 ] = Bsvd( diag( d ) + subdiag( uplo, e ) );
44  // Then,
45  // A = U1 U2 d V2^H V1^H;
46  // solving AX = C, it would be convenient that
47  // d (V1 V2)^H = apply(U2^H) apply(U1^H) C
48  // Here apply(.) is implicitly made and (V1 V2)^H is explicitly overwritten on the A.
49  // So, apply_Uh2C is a memory efficient way to solve a system of equations.
50  r_val = FLA_Bsvd_ext_opt_var1( n_iter_max,
51  d, e, G, H,
52  jobu, U, jobv, V,
53  apply_Uh2C, C,
54  b_alg );
55 
56  return r_val;
57 }
unsigned long dim_t
Definition: FLA_type_defs.h:71
FLA_Error FLA_Bsvd_ext_opt_var1(dim_t n_iter_max, FLA_Obj d, FLA_Obj e, FLA_Obj G, FLA_Obj H, FLA_Svd_type jobu, FLA_Obj U, FLA_Svd_type jobv, FLA_Obj V, FLA_Bool apply_Uh2C, FLA_Obj C, dim_t b_alg)
Definition: FLA_Bsvd_ext_opt_var1.c:13
int FLA_Error
Definition: FLA_type_defs.h:47
FLA_Error FLA_Bsvd_ext_check(FLA_Uplo uplo, FLA_Obj d, FLA_Obj e, FLA_Obj G, FLA_Obj H, FLA_Svd_type jobu, FLA_Obj U, FLA_Svd_type jobv, FLA_Obj V, FLA_Bool apply_Uh2C, FLA_Obj C)
Definition: FLA_Bsvd_ext_check.c:13
Definition: FLA_type_defs.h:158
dim_t FLA_Obj_vector_dim(FLA_Obj obj)
Definition: FLA_Query.c:137
unsigned int FLA_Check_error_level(void)
Definition: FLA_Check.c:18
FLA_Error FLA_Part_1x2(FLA_Obj A, FLA_Obj *A1, FLA_Obj *A2, dim_t nb, FLA_Side side)
Definition: FLA_View.c:110