https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/A-question-on-syntax-of-gemm/m-p/901217#M11269 <P>Hi, eveyone. I have a simple question on the syntax of ?gemm.</P> <P>In Intel MKL Reference Manual, the syntax of dgemm is</P> <P>dgemm(transa, transb, m, n, k, alpha, a, lda, b, ldb, beta, c, ldc)</P> <P>The parameter description of beta is "When beta is equal to zero, then c need not be set on input". I just don't quite understand the meaning of "c need not be set on input". If I merely want to do a matrix multiplication, say c=matmul(a,b). According to the description of ?gemm, c:=alpha*op(a)*op(b)+beta*c, I set beta equal zero. I expect the result should be c:=alpha*op(a)*op(b), however, what I get is c equals zero! So, what's the problem? What's the meaning of "c need not be set on input"?</P> <P>Thanks in advance!</P> Fri, 05 Feb 2010 07:50:07 GMT woshiwuxin 2010-02-05T07:50:07Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/A-question-on-syntax-of-gemm/m-p/901217#M11269 <P>Hi, eveyone. I have a simple question on the syntax of ?gemm.</P> <P>In Intel MKL Reference Manual, the syntax of dgemm is</P> <P>dgemm(transa, transb, m, n, k, alpha, a, lda, b, ldb, beta, c, ldc)</P> <P>The parameter description of beta is "When beta is equal to zero, then c need not be set on input". I just don't quite understand the meaning of "c need not be set on input". If I merely want to do a matrix multiplication, say c=matmul(a,b). According to the description of ?gemm, c:=alpha*op(a)*op(b)+beta*c, I set beta equal zero. I expect the result should be c:=alpha*op(a)*op(b), however, what I get is c equals zero! So, what's the problem? What's the meaning of "c need not be set on input"?</P> <P>Thanks in advance!</P> Fri, 05 Feb 2010 07:50:07 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/A-question-on-syntax-of-gemm/m-p/901217#M11269 woshiwuxin 2010-02-05T07:50:07Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/A-question-on-syntax-of-gemm/m-p/901218#M11270 <P>Hi,</P> <P>In case if beta is equal to zero matrix c will not be as input matrix and therefore c:=alpha*op(a)*op(b).</P> <P>But if c matrix is set with all rezos on input and beta is not equal to zero then the result will be the samebut withjust worseperformance.</P> <P></P> Fri, 05 Feb 2010 08:01:14 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/A-question-on-syntax-of-gemm/m-p/901218#M11270 barragan_villanueva_ 2010-02-05T08:01:14Z