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ddss_dsyr2k.c File Reference

LASs-DDSs ddss_dsyr2k routine. More...

`#include "../include/lass.h"`
Include dependency graph for ddss_dsyr2k.c:

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## Functions
int | ddss_dsyr2k (enum DDSS_UPLO UPLO, enum DDSS_TRANS TRANS, int N, int K, const double ALPHA, double *A, int LDA, double *B, int LDB, const double BETA, double *C, int LDC)

## Detailed Description

LASs-DDSs ddss_dsyr2k routine.

LASs-DDSs is a software package provided by: Barcelona Supercomputing Center - Centro Nacional de Supercomputacion

Author
  Pedro Valero-Lara pedro.nosp@m..val.nosp@m.ero@b.nosp@m.sc.e.nosp@m.s
  Boro Sofranac boro..nosp@m.sofr.nosp@m.anac@.nosp@m.bsc..nosp@m.es

Date
  2018-02-21

Definition in file ddss_dsyr2k.c.

## Function Documentation

int ddss_dsyr2k | ( | enum DDSS_UPLO | UPLO,
|  | enum DDSS_TRANS | TRANS,
|  | int | N,
|  | int | K,
|  | const double | ALPHA,
|  | double * | A,
|  | int | LDA,
|  | double * | B,
|  | int | LDB,
|  | const double | BETA,
|  | double * | C,
|  | int | LDC
| ) |  |

Performs one of the symmetric rank 2k operations:

    C = ALPHA * A * B**T + ALPHA * B * A**T + BETA * C or
    C = ALPHA * A**T * B + ALPHA * B**T * A + BETA * C

ALPHA and BETA are scalars, C is an N by N symmetric matrix and A and B are N by K matrices in the first case and K by N matrices in the second case.

Parameters

  [in] | UPLO | enum DDSS_UPLO. UPLO specifies the form in which C is stored: Lower: Lower triangular part of C is stored. The upper traingular part is not referenced. Upper: Upper triangular part of C is stored. The lower triangular part is not referenced.
  [in] | TRANS | enum DDSS_TRANS. TRANS specifies the operation to be performed as follows: NoTrans: C = ALPHA * A * B**T + ALPHA * B * A**T + BETA * C Trans: C = ALPHA * A**T * B + ALPHA * B**T * A + BETA * C
  [in] | N | int. N specifies the order of matrix C. N must be at least zero.
  [in] | K | int. With TRANS = NoTrans, K specifies the number of columns of the matrices A and B, and with TRANS = Trans, K specifies the number of rows of the matrices A and B. K must be at least zero.
  [in] | ALPHA | double. ALPHA specifies the scalar alpha.
  [in] | A | double *. A is a pointer to a matrix of dimension Na ( rows ) by Ka ( columns ), where Na is N and Ka is K when TRANS = NoTrans, and Na is K and Ka is N otherwise.
  [in] | LDA | int. LDA specifies the number of columns of A ( row-major order ). When TRANS = NoTrans then LDA must be at least max( 1, K ), otherwise LDA must be at least max( 1, N ).
  [in] | B | double *. B is a pointer to a matrix of dimension Nb ( rows ) by Kb ( columns ), where Nb is N and Kb is K when TRANS = NoTrans, and Nb is K and Kb is N otherwise.
  [in] | LDB | int. LDB specifies the number of columns of B ( row-major order ). When TRANS = NoTrans then LDB must be at least max( 1, K ), otherwise LDB must be at least max( 1, N ).
  [in] | BETA | double. BETA specifies the scalar beta.
  [in,out] | C | double *. C is a pointer to a matrix of dimension N by N. When UPLO = Uppper the strictly lower triangular part of C is not referenced. On exit, the upper triangular part of C is overwritten by the upper triangular part of the updated solution matrix C. When UPLO = Lower the strictly upper triangular part of C is not referenced. On exit, the lower triangular part of C is overwritten by the lower triangular part of the updated solution matrix C.
  [in] | LDC | int. LDC specifies the number of columns of C ( row-major order ). LDC must be at least max( 1, N ).

See also
  kdsyr2k

Definition at line 114 of file ddss_dsyr2k.c.

References kdsyr2k().

119 {
120 // Local variables
121 int nA, nB;
122
123 // Argument checking
124 if ( ( UPLO != Upper ) && ( UPLO != Lower ) )
125 {
126 fprintf( stderr, "Illegal value of UPLO, in ddss_dsyr2k code\n" );
127 return NoSuccess;
128 }
129
130 if ( ( TRANS != NoTrans ) && ( TRANS != Trans ) )
131 {
132 fprintf( stderr, "Illegal value of TRANS, in ddss_dsyr2k code\n" );
133 return NoSuccess;
134 }
135
136 if ( N < 0 )
137 {
138 fprintf( stderr, "Illegal value of N, in ddss_dsyr2k code\n" );
139 return NoSuccess;
140 }
141
142 if ( K < 0 )
143 {
144 fprintf( stderr, "Illegal value of K, in ddss_dsyr2k code\n" );
145 return NoSuccess;
146 }
147
148 if ( TRANS == NoTrans )
149 {
150 nA = nB = K;
151 }
152 else
153 {
154 nA = nB = N;
155 }
156
157 if ( LDA < MAX( 1, nA ) )
158 {
159 fprintf( stderr, "Illegal value of LDA, in ddss_dsyr2k code\n" );
160 return NoSuccess;
161 }
162
163 if ( LDB < MAX( 1, nB ) )
164 {
165 fprintf( stderr, "Illegal value of LDB, in ddss_dsyr2k code\n" );
166 return NoSuccess;
167 }
168
169 if ( LDC < MAX( 1, N ) )
170 {
171 fprintf( stderr, "Illegal value of LDC, in ddss_dsyr2k code\n" );
172 return NoSuccess;
173 }
174
175 // Quick return
176 if ( N == 0 || ( ( ALPHA == 0.0 || K == 0 ) && BETA == 1.0 ) )
177 {
178 return Success;
179 }
180
181 return kdsyr2k( UPLO, TRANS,
182 N, K,
183 ALPHA, A, LDA,
184 B, LDB,
185 BETA, C, LDC );
186
187 }
kdsyr2k
enum LASS_RETURN kdsyr2k(enum DDSS_UPLO UPLO, enum DDSS_TRANS TRANS, int N, int K, const double ALPHA, double *A, int LDA, double *B, int LDB, const double BETA, double *C, int LDC)
Definition: kdsyr2k.c:124