Maxima ezunits 中的比较（例如 <）在 Maxima 5.42.0 中比 5.41.0 慢很多
Comparisons (for example <) in Maxima's ezunits are a lot slower in Maxima 5.42.0 than 5.41.0
对我来说，运行这次比较的时间：1`g < 2`g Maxima 5.42.0（以及 5.42.2、5.43.0 和 5.43.2）似乎比 Maxima 慢很多在 5.41.0 中。 （请注意，第一个 运行 总是较慢。）
5.41.0 和 5.42.0 之间是否有可能导致这种速度下降的变化？还是我做错了什么？
示例 运行 次：
Maxima 5.41.0 与 SBCL 1.5.7
Maxima 5.41.0 http://maxima.sourceforge.net
using Lisp SBCL 1.5.7
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0000 elapsed) using 0 bytes.
(%o1) true
(%i2) load(ezunits);
Evaluation took 2.7650 seconds (2.7780 elapsed) using 1046.148 MB.
(%o2) /usr/local/share/maxima/5.41.0/share/ezunits/ezunits.mac
(%i3) 1`g < 1`g;
Evaluation took 0.0860 seconds (0.0860 elapsed) using 33.078 MB.
(%o3) 1 < 1
(%i4) 1`g < 1`g;
Evaluation took 0.0040 seconds (0.0040 elapsed) using 511.469 KB.
(%o4) 1 < 1
(%i5) 1`g < 1`g;
Evaluation took 0.0040 seconds (0.0040 elapsed) using 543.547 KB.
(%o5) 1 < 1
Maxima 5.42.0 与 SBCL 1.5.7
Maxima 5.42.0 http://maxima.sourceforge.net
using Lisp SBCL 1.5.7
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0010 elapsed) using 0 bytes.
(%o1) true
(%i2) load(ezunits);
Evaluation took 2.6460 seconds (2.6600 elapsed) using 1033.502 MB.
(%o2) /usr/local/share/maxima/5.42.0/share/ezunits/ezunits.mac
(%i3) 1`g < 2`g;
Evaluation took 1.0400 seconds (1.0400 elapsed) using 434.087 MB.
(%o3) 1 < 2
(%i4) 1`g < 2`g;
Evaluation took 0.4350 seconds (0.4360 elapsed) using 170.099 MB.
(%o4) 1 < 2
(%i5) 1`g < 2`g;
Evaluation took 0.4330 seconds (0.4340 elapsed) using 170.119 MB.
(%o5) 1 < 2
好像和Lisp版本无关
带有 Clisp 2.49 的 Maxima 5.42.0
Maxima 5.42.0 http://maxima.sourceforge.net
using Lisp CLISP 2.49 (2010-07-07)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0000 elapsed) using 56 bytes.
(%o1) true
(%i2) load(ezunits);
Evaluation took 5.4127 seconds (5.4136 elapsed) using 82.926 MB.
(%o2) /usr/local/share/maxima/5.42.0/share/ezunits/ezunits.mac
(%i3) 1`g < 2`g;
Evaluation took 1.7984 seconds (1.7984 elapsed) using 53.569 MB.
(%o3) 1 < 2
(%i4) 1`g < 2`g;
Evaluation took 0.1951 seconds (0.1951 elapsed) using 3.291 MB.
(%o4) 1 < 2
(%i5) 1`g < 2`g;
Evaluation took 0.1597 seconds (0.1598 elapsed) using 3.291 MB.
(%o5) 1 < 2
我在 Docker 中自己编译了 Maxima 和 Lisp 版本，所以我可以 运行 在 AWS Lambda 上使用以下命令：
wget --quiet --output-document sbcl-1.5.7-source.tar.bz2 https://sourceforge.net/projects/sbcl/files/sbcl/1.5.7/sbcl-1.5.7-source.tar.bz2/download \
&& tar --bzip2 -xf sbcl-1.5.7-source.tar.bz2 \
&& cd sbcl-1.5.7 \
&& sh make.sh "clisp" \
&& sh install.sh
wget --quiet --output-document maxima-5.42.0.tar.gz https://sourceforge.net/projects/maxima/files/Maxima-source/5.42.0-source/maxima-5.42.0.tar.gz/download \
&& tar -xzvf maxima-5.42.0.tar.gz \
&& cd maxima-5.42.0 \
&& ./configure --enable-sbcl-exec \
&& make \
&& make install
更新
我们已尝试自行调查此问题。不幸的是，我们对 lisp 的经验不足，无法找到解决方案。
我们确实发现，当我们使用 GCL 的 Maxima 5.43.0 预编译版本时，性能很好。该版本可以在这里找到：https://sourceforge.net/projects/maxima/files/Maxima-Linux/5.43.0-Linux/
Maxima 5.43.0 与 GCL 2.6.12
Maxima 5.43.0 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.12
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0000 elapsed)
(%o1) true
(%i2) load(ezunits);
Evaluation took 0.4100 seconds (0.5600 elapsed)
(%o2) /usr/share/maxima/5.43.0/share/ezunits/ezunits.mac
(%i3) 1`g < 2`g;
Evaluation took 0.1700 seconds (0.1700 elapsed)
(%o3) 1 < 2
(%i4) 1`g < 2`g;
Evaluation took 0.0500 seconds (0.0500 elapsed)
(%o4) 1 < 2
这也是 运行 在 docker 容器中。使用这些命令安装了 Maxima：
wget --quiet https://downloads.sourceforge.net/project/maxima/Maxima-Linux/5.43.0-Linux/maxima-5.43.0-1.x86_64.rpm \
&& wget --quiet https://downloads.sourceforge.net/project/maxima/Maxima-Linux/5.43.0-Linux/maxima-exec-gcl-5.43.0-1.x86_64.rpm \
&& rpm --install --verbose --hash maxima-5.43.0-1.x86_64.rpm maxima-exec-gcl-5.43.0-1.x86_64.rpm
跟踪一些涉及的函数，看起来处理1 ` g < 2 ` g的大部分时间花在了dimensions，这是一个计算维度（质量，时间）的函数、长度等）的单位，而在 dimensions 中，大部分时间都花在名为 rff 的表达式匹配规则中，如下所示：
(%i22) disprule(rff);
(%t22) rff : dimensions(ff%) -> block([ff%2 :
ev(ff%, args(known_unit_conversions), infeval)],
if ff%2 # ff% then dimensions(ff%2) else dimensions(ff%))
这里ff%是一个符号，比如g。 rff的作用是将g转换为kg/1000，然后其他一些规则对kg（和1000）进行运算，求出维度是 mass。
ev(ff%, args(known_unit_conversions), infeval) 是一种查找基本单位的简单方法，但正如您所指出的，它相对较慢，因为它将整个单位转换列表带入画面，而实际上只有一个是需要。我同意一种更有效的方法是可取的，因为它可能会加快一般单元的操作。请随时提交有关此问题的错误报告 (https://sourceforge.net/p/maxima/bugs/)。
我没有查看提交历史，所以我不知道版本之间发生了什么变化。无论如何，目前版本的瓶颈在哪里似乎很清楚。
对我来说，运行这次比较的时间：1`g < 2`g Maxima 5.42.0（以及 5.42.2、5.43.0 和 5.43.2）似乎比 Maxima 慢很多在 5.41.0 中。 （请注意，第一个 运行 总是较慢。）
5.41.0 和 5.42.0 之间是否有可能导致这种速度下降的变化？还是我做错了什么？
示例 运行 次：
Maxima 5.41.0 与 SBCL 1.5.7
Maxima 5.41.0 http://maxima.sourceforge.net
using Lisp SBCL 1.5.7
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0000 elapsed) using 0 bytes.
(%o1) true
(%i2) load(ezunits);
Evaluation took 2.7650 seconds (2.7780 elapsed) using 1046.148 MB.
(%o2) /usr/local/share/maxima/5.41.0/share/ezunits/ezunits.mac
(%i3) 1`g < 1`g;
Evaluation took 0.0860 seconds (0.0860 elapsed) using 33.078 MB.
(%o3) 1 < 1
(%i4) 1`g < 1`g;
Evaluation took 0.0040 seconds (0.0040 elapsed) using 511.469 KB.
(%o4) 1 < 1
(%i5) 1`g < 1`g;
Evaluation took 0.0040 seconds (0.0040 elapsed) using 543.547 KB.
(%o5) 1 < 1
Maxima 5.42.0 与 SBCL 1.5.7
Maxima 5.42.0 http://maxima.sourceforge.net
using Lisp SBCL 1.5.7
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0010 elapsed) using 0 bytes.
(%o1) true
(%i2) load(ezunits);
Evaluation took 2.6460 seconds (2.6600 elapsed) using 1033.502 MB.
(%o2) /usr/local/share/maxima/5.42.0/share/ezunits/ezunits.mac
(%i3) 1`g < 2`g;
Evaluation took 1.0400 seconds (1.0400 elapsed) using 434.087 MB.
(%o3) 1 < 2
(%i4) 1`g < 2`g;
Evaluation took 0.4350 seconds (0.4360 elapsed) using 170.099 MB.
(%o4) 1 < 2
(%i5) 1`g < 2`g;
Evaluation took 0.4330 seconds (0.4340 elapsed) using 170.119 MB.
(%o5) 1 < 2
好像和Lisp版本无关
带有 Clisp 2.49 的 Maxima 5.42.0
Maxima 5.42.0 http://maxima.sourceforge.net
using Lisp CLISP 2.49 (2010-07-07)
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0000 elapsed) using 56 bytes.
(%o1) true
(%i2) load(ezunits);
Evaluation took 5.4127 seconds (5.4136 elapsed) using 82.926 MB.
(%o2) /usr/local/share/maxima/5.42.0/share/ezunits/ezunits.mac
(%i3) 1`g < 2`g;
Evaluation took 1.7984 seconds (1.7984 elapsed) using 53.569 MB.
(%o3) 1 < 2
(%i4) 1`g < 2`g;
Evaluation took 0.1951 seconds (0.1951 elapsed) using 3.291 MB.
(%o4) 1 < 2
(%i5) 1`g < 2`g;
Evaluation took 0.1597 seconds (0.1598 elapsed) using 3.291 MB.
(%o5) 1 < 2
我在 Docker 中自己编译了 Maxima 和 Lisp 版本，所以我可以 运行 在 AWS Lambda 上使用以下命令：
wget --quiet --output-document sbcl-1.5.7-source.tar.bz2 https://sourceforge.net/projects/sbcl/files/sbcl/1.5.7/sbcl-1.5.7-source.tar.bz2/download \
&& tar --bzip2 -xf sbcl-1.5.7-source.tar.bz2 \
&& cd sbcl-1.5.7 \
&& sh make.sh "clisp" \
&& sh install.sh
wget --quiet --output-document maxima-5.42.0.tar.gz https://sourceforge.net/projects/maxima/files/Maxima-source/5.42.0-source/maxima-5.42.0.tar.gz/download \
&& tar -xzvf maxima-5.42.0.tar.gz \
&& cd maxima-5.42.0 \
&& ./configure --enable-sbcl-exec \
&& make \
&& make install
更新
我们已尝试自行调查此问题。不幸的是，我们对 lisp 的经验不足，无法找到解决方案。
我们确实发现，当我们使用 GCL 的 Maxima 5.43.0 预编译版本时，性能很好。该版本可以在这里找到：https://sourceforge.net/projects/maxima/files/Maxima-Linux/5.43.0-Linux/
Maxima 5.43.0 与 GCL 2.6.12
Maxima 5.43.0 http://maxima.sourceforge.net
using Lisp GNU Common Lisp (GCL) GCL 2.6.12
Distributed under the GNU Public License. See the file COPYING.
Dedicated to the memory of William Schelter.
The function bug_report() provides bug reporting information.
(%i1) showtime:true;
Evaluation took 0.0000 seconds (0.0000 elapsed)
(%o1) true
(%i2) load(ezunits);
Evaluation took 0.4100 seconds (0.5600 elapsed)
(%o2) /usr/share/maxima/5.43.0/share/ezunits/ezunits.mac
(%i3) 1`g < 2`g;
Evaluation took 0.1700 seconds (0.1700 elapsed)
(%o3) 1 < 2
(%i4) 1`g < 2`g;
Evaluation took 0.0500 seconds (0.0500 elapsed)
(%o4) 1 < 2
这也是 运行 在 docker 容器中。使用这些命令安装了 Maxima：
wget --quiet https://downloads.sourceforge.net/project/maxima/Maxima-Linux/5.43.0-Linux/maxima-5.43.0-1.x86_64.rpm \
&& wget --quiet https://downloads.sourceforge.net/project/maxima/Maxima-Linux/5.43.0-Linux/maxima-exec-gcl-5.43.0-1.x86_64.rpm \
&& rpm --install --verbose --hash maxima-5.43.0-1.x86_64.rpm maxima-exec-gcl-5.43.0-1.x86_64.rpm
跟踪一些涉及的函数，看起来处理1 ` g < 2 ` g的大部分时间花在了dimensions，这是一个计算维度（质量，时间）的函数、长度等）的单位，而在 dimensions 中，大部分时间都花在名为 rff 的表达式匹配规则中，如下所示：
(%i22) disprule(rff);
(%t22) rff : dimensions(ff%) -> block([ff%2 :
ev(ff%, args(known_unit_conversions), infeval)],
if ff%2 # ff% then dimensions(ff%2) else dimensions(ff%))
这里ff%是一个符号，比如g。 rff的作用是将g转换为kg/1000，然后其他一些规则对kg（和1000）进行运算，求出维度是 mass。
ev(ff%, args(known_unit_conversions), infeval) 是一种查找基本单位的简单方法，但正如您所指出的，它相对较慢，因为它将整个单位转换列表带入画面，而实际上只有一个是需要。我同意一种更有效的方法是可取的，因为它可能会加快一般单元的操作。请随时提交有关此问题的错误报告 (https://sourceforge.net/p/maxima/bugs/)。
我没有查看提交历史，所以我不知道版本之间发生了什么变化。无论如何，目前版本的瓶颈在哪里似乎很清楚。