Terminal Commands

Simple compilation

gfortran my_program.f90 -o my_program

Compiling only

gfortran -c my_program.f90

Multi-thread compilation

caf my_program.f90 -o my_program

Multi-thread execution

cafrun -n x ./my_program

where x is the number of images

note

• $! can be used to speed up command typing

Fortran commands

Variable initialization

Initialization statement

single variable initialization

data_type :: variable_name

Array initialization

data_type :: array_name(n)
data_type, dimension(n) :: array_name

Finally don’t need to indexing with (y, x) lol

Coarray initialization

data_type :: array_name(n)[*]

Constant initialization

data_type, parameter :: const_name = xxx

Variable type

integer :: i, n
real :: x
complex :: c = (a, b)

note

• a constant can be used to initialize other variables
• constant’s value must be provided on initialization

specific kind of variable

use iso_fortran_env
integer(kind = int32) :: n

Control flow statements

if statement

if (condition) !...

if (condition) then
    !...
end if

if (condition) then
    !...
else if (other_condition) then
    !...
end if

do loop

do n = start, end
    !...
end do

do n = start, end, increment
    !...
end do

!named loop
outer_loop: do j = 1, jm
    inner_loop: do i = 1, im
        !...
    end do inner_loop
end do outer_loop

Fortran program units

program: the only unit can be invoked as an executable from the operating system

program xxx
    implicit none 
    integer :: a, b !declaration of variables

    if a == 1 call add(a, b) !invoke a subroutine
end program

function: Invoked in expressions, return only one value.

function sum(a,b)
    integer, intent(in) :: a, b
    integer :: sum

    sum = a + b
end function sum

OR

integer function sum(a,b)
    integer, intent(in) :: a, b
    ! no need to define sum

    sum = a + b
end function sum

OR

integer function sum(a,b) results(res)
    integer, intent(in) :: a,b

    res = a+b
end function sum

subroutine: Invoked with a call statement.

subroutine add(a,b)
    integer, intent(inout) :: a
    integer, intent(in) :: b
    a = a+b
    print *, 'a=', a
end subroutine add

Attributes

pure : indicate the function has no side effects. This includes modifying the value of a variable declared outside the procedure.

elemental : allows receiving array arguments in place of scalars

pure elemental integer function sum(a,b)
    integer, intent(in) :: a, b
    sum = a+b
end function sum

sum([1,2], 3) ! is valid
sum([1,2], [3,4]) ! is valid
sum([1,2,3], [4,5]) ! is not valid as arrays are not of the same shape.

optional argument

subroutine add(a, b, res, debug)
    integer, intent(in) :: a, b
    integer, intent(out) :: res
    logical, intent(in), optional :: debug

    if (present(debug)) then
        if (debug) then
            !...
        end if
    end if

    res = a + b
end subroutine add

modules

import module

use iso_fortran_env, only: int32, real32

rename entity when import

use mod_atmosphere, only: temperature
use mod_ocean, only: temperature_ocean => temperature, velocity_ocean => velocity

=> means point to

Module variable

module mod_circle
    implicit none
    private :: pi
    real, parameter :: pi = 3.14159265
contains
    !...
end module mod_circle

Parallel programming commands

Parallel programming image indexing

get current image number

this_image()

get total image number

num_images()

wait and sync

sync all

Parallel programming flow statements

embarrassingly parallel iteration

do concurrent (i = 1:grid_size)
    !...
end do

令人吐槽的点

• opencoarray一直架在一个并非mpi协议规定的特性上
• mpich 非标准目录结构
• opencoarray的古早CMakeList

P.S. 而且为什么sublime的fortran plugin需要自己下载并编译而不在官方包管理器里啊。

Two signal systems

• PZB
• LZB

Light signal

Two types of signals

• main signal
• distance signal

Main signal

Green Clear to proceed at current line speed

Green over yellow Proceed at 40 km/h

Red Stop at this signal

White number on top of signal Indicate speed of proceeding

Blinking green Proceed at line speed, expect to slow down at next signal.

Distance signal

Indicate the main signal ahead. Lights are at diagonal angle. White light indicate this distance signal is closer to main signal than usual.

Double green

Next main signal is clear

Green over yellow Proceed at 40 km/h

Two yellow lights Expect to stop at next main signal

Shunt signal

Two horizontal red light Not clear to proceed

Two diagonal white light Clear to proceed at 40 km/h

PZB

There are three modes for PZB. The number for each mode indicate the speed to reduce to when passing cautionary signal (diagonal yellow).

• O mode for passenger train, illuminate 85.

PZB control

PZB acknowledge

Pgdown

PZB release

end

PZB overide

del

SOP

Passing cautionary signal

1. Press acknowledge when pass cautionary signal
2. 1000hz magnet light up
3. reduce speed to below 85 km/h
4. When 1000Hz magnet light off. If the path is clear ahead, press PZB release and accelerate. If not clear, decrease speed to 65 km/h.
5. When 500Hz magnet light up, decelerate to 45 km/h.
6. Stop before red signal
7. If get permission from the signaler, press and hold the overide button and move forward.
8. Keep speed below 40 km/h after passing this way untile travel 2km or pass a clear signal. After which press pzb release and accelerate.

note

• No need for acknowledge of 500Hz magnet
• Can’t go over 45 km/h after passing 500Hz even if signal is clear. The restriction last for 250m pass the signal.

LZB

Indicate by the U light.

When AFB active, the speed automatically adjust.

B lamp indicate whether auto braking is active. G lamp indicate it is faster than the braking curve allows.

When reaching end of LZB section

1. ende light up
2. press PZB acknowledge

Signs

Speed Post

Show speed limit divide by ten. Arrow above the post indicates the track this speed limit applies to.

Speed Limit Warning Post

Indicate the upcoming speed change. May contain pzb magnet.

Distance Marker Post

Represent distance to an upcoming signal. 3 stripes — 250m; 2 stripes — 175m; 1 stripe — 100m.

Hectometer Post

Exist every 200m. Indicate location from a location.

P Sign

Sound horn when passing P sign.

H Sign

Indicate stopping location.

Credit to PTGRail for the amazing video he made about this topic.

After a bit of investigation, I found although the dGPU is not waked during a reboot, bios power it up during waking up from suspension, and makes it stuck at D0.

The stuck was caused by the power control switched to on after the reboot. Therefore, this problem can be solved by writing a script than automatically set the power control back to auto after suspension. This can be down using a simple bash program.

Here is how I diagnosed and fixed the issue when my stylus was recognized as a device but wouldn’t move the pointer.

Step 1: Verification (The “Before” State)

Even without configuration, Linux often “sees” the hardware. I started by checking if the kernel was receiving signals.

• Command: sudo evtest
• Result: I selected the ELAN9008 device. Moving the pen showed a stream of $ABS_X$ and $ABS_Y$ coordinates.
• What this told me: The hardware is fine. The screen digitizer is working, and the kernel driver (hid-multitouch) is active. The problem lies higher up.

Step 2: Bridging the Gap with libwacom

KDE Plasma relies on a library called libwacom to identify tablets. If THE device isn’t in its database, the “Graphics Tablet” settings page in KDE will be empty or missing features.

• The Problem: libwacom-list-local-devices showed the device was “not supported.”
• The Fix: I created a custom tablet definition file at /etc/libwacom/elan-9008.tablet.
• The Data:

[Device]
Name=ELAN9008:00 04F3:40FD Stylus
DeviceMatch=i2c|04f3|40fd
Class=ISDV4
IntegratedIn=Display;System
Styli=@generic-with-eraser;

• Why this helped: This “introduced” the stylus to the system. After running sudo libwacom-update-db, the Graphics Tablet section finally appeared in my KDE System Settings.

Step 3: Debugging the “Flicker” (Wayland Input)

Even with the settings page visible, the cursor would only “flicker” or appear/disappear without actually moving.

• Command: libinput debug-events
• Observation: This tool showed TABLET_TOOL_AXIS events with perfect coordinates.
• What this told me: libinput was correctly processing the movement, but KWin was dropping the data.

Step 4: The Final Boss – The Calibration Matrix

This was the “Aha!” moment. I checked the KDE input configuration file to see how it was mapping the pen to the pixels.

• Command: grep -A 20 "ELAN9008" ~/.config/kcminputrc
• The Discovery: The CalibrationMatrix was filled with scientific notation numbers like 1.19e-07 (effectively 0).
• The Fix: I manually edited ~/.config/kcminputrc and reset the matrix to the Identity Matrix:

  CalibrationMatrix=1,0,0,0,1,0,0,0,1
  

Summary

1. Check Hardware: Use evtest to ensure the kernel sees the pen.

2. Identify for UI: Create a .tablet file so libwacom and KDE recognize the device.

3. Check libinput: Ensure debug-events shows axis movement.

4. Fix the Math: Reset the CalibrationMatrix in kcminputrc to identity matrix.

The reason it’s confusing is that applications like Discord control the microphone gain from their end. This keeps the volume from being loud enough to immediately identify as a gain issue, though the constant popping and high sensitivity indicate otherwise.

For anyone using ALSA, the fix is as simple as getting into alsamixer and manually changing the gain of the internal microphone.

My original plan was to create a new physical volume and add it to the LVM. However, since I had not yet stored any important documents on the system, I decided to directly increase the size of the existing volume. Here are the steps I took:

First, the most important step is to create backups. Keep recovery images for both systems on a separate drive in case anything goes wrong. Before starting any disk operations, I recommend creating a Ventoy USB drive with GParted Live, Arch Linux, and Windows installation ISOs. I also recommend saving a backup of the partition table to the same USB drive.

I used DiskGenius to decrease the Windows volume size and GParted to increase the LVM volume size. You could theoretically use GParted for both operations, but DiskGenius is known for having better support for Windows. The only issue I had in this process was that the LVM was mounted for some reason, which I didn’t notice initially. Therefore, be sure to unmount all volumes using umount -a before proceeding.

After moving the LVM, we need to fix GRUB. This guide from GParted was very useful. For Arch users, this process can be further simplified by booting into an Arch Live environment.

For Arch users with an LVM on a UEFI system, the process I used was as follows:

# 1.activate LVM logic volume
vgchange -ay

# 2.mount root logic volume to /mnt
mount /dev/vg_arch/root /mnt

# 3.mount the efi partition
mkdir -p /mnt/boot/efi
mount /dev/nvme0n1p1 /mnt/boot/efi

# 4.chroot into the original system
arch-chroot /mnt

# 5.re-install GRUB to ESP partition
grub-install --target=x86_64-efi --efi-directory=/boot/efi /dev/nvme0n1

# 6.regen init ramdisk
mkinitcpio -P

# 7.regen GRUB config file
grub-mkconfig -o /boot/grub/grub.cfg

# 8.exit and reboot
exit
umount -R /mnt
reboot

• Add executable to steam
• Place the game file in the virtual C
• Perform integrity check before launching
• Ignore the error 9041-0-0
• Enjoy the game

Since I have switched my daily OS to arch, I naturally want to minimize the time I have to boot back to Windows. Obviously professional softwares like Catia or Ansys(which is buggy even on Windows) are hard to run on linux, but I could as least try and run all my games in linux. Thanks to the consant investment in compatibility from valve, all the steam titles can run smoothly without any pain. The only remaining game is ZenlessZoneZero.

Initially I tried to run it on standard wine, but a weird error of constant relaunching hit me, and I decided to instead using proton for this mihoyo game.

The launcher installed via steam flawlessly. After putting the game file into the virtual C under ~/.local/share/Steam/steamapps/compatdata/game_id/pfx/drive_c/Program Files/miHoYo Launcher/game/, the launcher was capable of detecting it instantaneously. Success seemed imminent.

However, the game entered a black screen after the initial logo appeared. To fix this, I ran an integrity check to prevent any file corruption from the migration. That’s when I hit a wall: the post-check download failed with error 9041-0-0, a cryptic parity-check failure.

After a few more attempt of revalidation, I decided on a last-ditch effort: bypassing the launcher entirely. By running the game executable directly from steam, the game launched perfectly, bypassing the broken launcher logic entirely.

In order to make the launching process more convenient, we can also add the application to application menu. However, the steamgameid for non-steam game can only be obtained using the “add desktop shortcut” function of steam. After creating the shortcut, we can move the file to the application menu directory using command mv ~/Desktop/zenlesszonezero.desktop ~/.local/share/applications/. To improve the looking, we can change the icon by editing the desktop file nano ~/.local/share/applications/ZenlessZoneZero.desktop and replace (or add) the entry Icon=~/.local/share/Steam/steamapps/compatdata/game_id/pfx/drive_c/Program Files/miHoYo Launcher/1.12.0.303/ico/nap_cn.ico.

The process of getting steamgameid part was inspired by this blog by “洛元”. I am confused why valve decided to use different id for the directory and the execution command.

2025年，稳定又变化。剑桥重复的流程，让人很难感受到年份的实感。周围太多人进入了下一个阶段，而我仍未知我的信息是否足够支持下一步的决定。今年太多的突发事件让我不断在信息不足时调整流程，完成了许多事，但也留下了许多遗憾。所幸，无论在哪，家人与朋友总会握紧我的手，给我信心来做出决定。接受，并感谢2025年的我所执行的一切，从中汲取必须的知识，并开始新的一年。