http://www.mapleprimes.com/posts/39188-Numerical-Precision en-us 2026 Maplesoft, A Division of Waterloo Maple Inc. Maplesoft Document System Fri, 12 Jun 2026 10:50:23 GMT Fri, 12 Jun 2026 10:50:23 GMT The latest comments added to the Post, Numerical Precision http://www.mapleprimes.com/images/mapleprimeswhite.jpg http://www.mapleprimes.com/posts/39188-Numerical-Precision http://www.mapleprimes.com/posts/39188-Numerical-Precision?ref=Feed:MaplePrimes:Numerical Precision:Comments#comment71159 <p>To create Matrices and Vectors with double precision real (C double) entries, stored in contiguous memory arrays, use the option datatype=float[8] when calling the Matrix and Vector constructors. And similarly use complex[8] for paired hardware doubles representing complex entries.</p> <p>To ensure that the LinearAlgebra operations with these float[8] Matrices and Vectors always is done using hardware double precision external libraries (and not with arbitrary precision software float external libraries) then do the following:</p> <ul> <li>set UseHardwareFloats:=true;</li> <li>(or) keep Digits less than evalhf(Digits)</li> </ul> <p>You might also try setting infolevel[LinearAlgebra]:=2 since that will allow LinearAlgebra commands to print additional information about which external routine is being used, and about whether copying from hardware to software datatypes is taking place. (The external function hw_f06ecf is hardware BLAS function daxpy, for example, while sw_f06ecf is the software float equivalent. The hw_ or sw_ prefix which can appear in this printed information is thus a key.)</p> <p>The <b>option hfloat</b> switch for a procedure does <i>not</i> accomplish the items above. That is to say, it does <i>not</i> enable float[8] Matrix and Vector construction without the explicit datatype options being provided, it does <i>not </i>enforce use of hardware external libraries, and it does <i>not</i> prevent internal software float Matrix/Vector copying.</p> <p>Instead, the hfloat option of a procedure affects scalars. It toggles the automatic creation of scalar floats as HFloat objects, and it toggles the retrieval of scalar entries from float[8] Matrices and Vectors also to be HFloat objects.</p> <p>acer</p> The latest comments added to the Post, Numerical Precision 71159 Tue, 10 Jun 2008 20:59:08 Z acer acer http://www.mapleprimes.com/posts/39188-Numerical-Precision?ref=Feed:MaplePrimes:Numerical Precision:Comments#comment83372 <p>Brilliant, thanks very much!</p> The latest comments added to the Post, Numerical Precision 83372 Wed, 11 Jun 2008 15:45:40 Z py9mrg py9mrg