Note: Patch 2 uses modified excerpts of the "doubledouble" arithmetic package written and copyrighted by Keith Briggs. It is based on ideas developed by Keith and others noted in his source files, including W. Kahan. Keith has permitted it to be distributed under the same license that covers QMG 2.0. "Doubledouble" arithmetic simulates 106-bit arithmetic using two IEEE double-precision numbers. It will works only on computers that follow the IEEE standard. For more information, see the official home page of doubledouble. QMG invokes doubledouble arithmetic for arithmetic with curved patches in the case that it detects a degeneracy with the patch.
The standard distribution of doubledouble is covered by the Gnu Public License. It is recommended that you obtain the standard distribution if you plan to use double-double arithmetic in another project since the standard distribution is more functional and may have more bug-fixes. If you plan to use the doubledouble subset of QMG in a separate project, there are additional license terms that apply; see the new version of copyright shipped with QMG.
See the source files for more information about the background of the doubledouble package.
If you already have downloaded QMG 2.0, then you can make the patches yourself following these instructions. First follow all the instructions for Patch 1. Then follow these instructions.
copyrightin QMGROOT and
copyright.htmlin QMGROOT/doc. The remaining files should all be saved in directory QMGROOT/src/common/. Next, make the following changes to other files.
Note that this instruction may or may not apply to you. If it applies, then you should update custom following this instruction.
# If you are using a Pentium or compatible processor, add -Dx86 to ADDITIONAL_DEFINES.