BLAS function syntax

void sgemv(const char *trans, int *m, int *n, float *alpha,
					void *a, int *lda, void *x, int *incx, 
					float *beta, void *y, int *incy);

void dgemv(const char *trans, int *m, int *n, double *alpha,
					void *a, int *lda, void *x, int *incx,
				  double *beta, void *y, int *incy);

trans

is a single character indicating the form of input matrix a, where:

• 'N' or 'n' indicates that a is to be used in computation
• 'T' or 't' indicates that the transpose of a is to be used in computation

m

represents:

• the number of rows in input matrix a
• the length of vector y, if 'N' or 'n' is used for the trans parameter
• the length of vector x, if 'T' or 't' is used for the trans parameter

The number of rows must be greater than or equal to zero, and less than the leading dimension of matrix a (specified in lda)

n

represents:

• the number of columns in input matrix a
• the length of vector x, if 'N' or 'n' is used for the trans parameter
• the length of vector y, if 'T' or 't' is used for the trans parameter

The number of columns must be greater than or equal to zero.

alpha

is the scaling constant for matrix a

a

is the input matrix of float (for sgemv) or double (for dgemv) values

lda

is the leading dimension of the array specified by a. The leading dimension must be greater than zero. The leading dimension must be greater than or equal to 1 and greater than or equal to the value specified in m.

x

is the input vector of float (for sgemv) or double (for dgemv) values.

incx

is the stride for vector x. It can have any value.

beta

is the scaling constant for vector y

y

is the output vector of float (for sgemv) or double (for dgemv) values.

incy

is the stride for vector y. It must not be zero.

void sgemm(const char *transa, const char *transb,
   int *l, int *n, int *m, float *alpha,
   const void *a, int *lda, void *b, int *ldb,
   float *beta, void *c, int *ldc);

void dgemm(const char *transa, const char *transb,
   int *l, int *n, int *m, double *alpha, 
   const void *a, int *lda, void *b, int *ldb, 
   double *beta, void *c, int *ldc);

transa

is a single character indicating the form of input matrix a, where:

• 'N' or 'n' indicates that a is to be used in computation
• 'T' or 't' indicates that the transpose of a is to be used in computation

transb

is a single character indicating the form of input matrix b, where:

• 'N' or 'n' indicates that b is to be used in computation
• 'T' or 't' indicates that the transpose of b is to be used in computation

l

represents the number of rows in output matrix c. The number of rows must be greater than or equal to zero, and less than the leading dimension of c.

n

represents the number of columns in output matrix c. The number of columns must be greater than or equal to zero.

m

represents:

• the number of columns in matrix a, if 'N' or 'n' is used for the transa parameter
• the number of rows in matrix a, if 'T' or 't' is used for the transa parameter

and:

• the number of rows in matrix b, if 'N' or 'n' is used for the transb parameter
• the number of columns in matrix b, if 'T' or 't' is used for the transb parameter

m must be greater than or equal to zero.

alpha

is the scaling constant for matrix a

a

is the input matrix a of float (for sgemm) or double (for dgemm) values

lda

is the leading dimension of the array specified by a. The leading dimension must be greater than zero. If transa is specified as 'N' or 'n', the leading dimension must be greater than or equal to 1. If transa is specified as 'T' or 't', the leading dimension must be greater than or equal to the value specified in m.

b

is the input matrix b of float (for sgemm) or double (for dgemm) values.

ldb

is the leading dimension of the array specified by b. The leading dimension must be greater than zero. If transb is specified as 'N' or 'n', the leading dimension must be greater than or equal to the value specified in m. If transa is specified as 'T' or 't', the leading dimension must be greater than or equal to the value specified in n.

beta

is the scaling constant for matrix c

c

is the output matrix c of float (for sgemm) or double (for dgemm) values.

ldc

is the leading dimension of the array specified by c. The leading dimension must be greater than zero. If transb is specified as 'N' or 'n', the leading dimension must be greater than or equal to 0 and greater than or equal to the value specified in l.