https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861109#M7528 I need to multiply two large non-square matrices that will not fit in memory. The result is a square matrix that will fit in memory. I am looking for sample code that shows how to do a blocked matrix multiply. I note this from Wikipedia. <BR /> <BR />"By decomposing one or both of the input matrices into block matrices, GEMM can be used repeatedly on the smaller blocks to build up a result for the full matrix. This is one of the motivations for including the parameter, so the results of previous blocks can be accumulated" <BR />Googling has not turned up anything so far.... <BR /> <BR /> <BR /> Tue, 08 Jul 2008 15:45:46 GMT AndrewC 2008-07-08T15:45:46Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861109#M7528 I need to multiply two large non-square matrices that will not fit in memory. The result is a square matrix that will fit in memory. I am looking for sample code that shows how to do a blocked matrix multiply. I note this from Wikipedia. <BR /> <BR />"By decomposing one or both of the input matrices into block matrices, GEMM can be used repeatedly on the smaller blocks to build up a result for the full matrix. This is one of the motivations for including the parameter, so the results of previous blocks can be accumulated" <BR />Googling has not turned up anything so far.... <BR /> <BR /> <BR /> Tue, 08 Jul 2008 15:45:46 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861109#M7528 AndrewC 2008-07-08T15:45:46Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861110#M7529 There is an example in Numerical recipes which does this - the computational load is better too - N^2.7 rather than N^3.<BR /><BR /> Tue, 08 Jul 2008 15:50:31 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861110#M7529 Basden__Alastair 2008-07-08T15:50:31Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861111#M7530 That would be the third edition , I assume, as I see no reference to blocked matrix multiply in the earlier editions. Do you know if the blocked multiply they implement can handle non-square blocks in the source matrices? Tue, 08 Jul 2008 16:22:19 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861111#M7530 AndrewC 2008-07-08T16:22:19Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861112#M7531 Unfortunately that NR section was not useful at all as they are only talking in the most general terms and do not provide a concrete example. Tue, 08 Jul 2008 17:43:38 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861112#M7531 AndrewC 2008-07-08T17:43:38Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861113#M7532 I found what I needed. Google search for "The Science of Programming Matrix Computations" Tue, 08 Jul 2008 20:28:10 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861113#M7532 AndrewC 2008-07-08T20:28:10Z https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861114#M7533 Just incase it helps anyone... Numerical recipes in C second edition, page 102, section heading is "is matrix inversion an N^3 process", and in this section it gives Strassen formula for matrix multiply which is blocked, and also slightly faster than the normal approach.<BR /> Wed, 09 Jul 2008 10:15:01 GMT https://community.intel.com/t5/Intel-oneAPI-Math-Kernel-Library/Looking-for-example-of-blocked-multiply-using-GEMM/m-p/861114#M7533 Basden__Alastair 2008-07-09T10:15:01Z