E: Sub-process /usr/bin/dpkg returned an error code (1) – but how do I find the meaningful error messages in APT’s output?

I have encountered various package management problems that cause APT commands to fail with output that ends with this line:

E: Sub-process /usr/bin/dpkg returned an error code (1) 

Occasionally other error codes may appear such as 100 which means dpkg is not there, but 1 is the most common error code.

Unfortunately this error code tells me almost nothing about what actually caused the error or how I should solve it. Almost every package management issue I see, regardless of its cause or solution, produces the same error!

So, where will I find the useful part of the output, which I can search for online or ask questions about on Ask Ubuntu?

No DispalyPort option in audio output device menu, Nvidia Drivers

I can’t get my DisplayPort-connected monitor (AW2518HF, external speakers connected) to show up on this drop-down menu: Settings > Sound > Output > Output Device.

I’ve opened Nvidia X Server Settings and can assure that DP Audio is enabled. Additionally, I booted Windows 7 and was able to select it and play sound just fine.

I’m using a GTX 750 (EVGA; they added a DP port in their version) with the 418 driver installed from Software & Updates on Ubuntu 19.04.

Here’s aplay -l

**** List of PLAYBACK Hardware Devices **** card 0: PCH [HDA Intel PCH], device 0: ALC887-VD Analog [ALC887-VD Analog]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 1: NVidia [HDA NVidia], device 3: HDMI 0 [HDMI 0]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 1: NVidia [HDA NVidia], device 7: HDMI 1 [HDMI 1]   Subdevices: 1/1   Subdevice #0: subdevice #0 card 1: NVidia [HDA NVidia], device 8: HDMI 2 [HDMI 2]   Subdevices: 1/1   Subdevice #0: subdevice #0 

I my system sound ouput is not working in all the ports.I check sudo apt -get update it shows like this.What i need to do for the output sound?

sudo apt-get update
Err:13 http://ppa.launchpad.net/ubuntu-audio-dev/ppa/ubuntu bionic Release
404 Not Found [IP: 91.189.95.83 80] Reading package lists… Done
E: The repository ‘http://ppa.launchpad.net/ubuntu-audio-dev/ppa/ubuntu bionic Release’ does not have a Release file. N: Updating from such a repository can’t be done securely, and is therefore disabled by default. N: See apt-secure(8) manpage for repository creation and user configuration details.

Can’t read process output with cat and tail

I have a simple example of writing to stdout:

import datetime import time   if __name__ == '__main__':      while True:         print('time is {}'.format(datetime.datetime.now().time()))         time.sleep(5) 

Then I did:

python main.py & echo $  ! 

to run my process and get its PID.

My purpose is reading from stdout of my current process above, but all of these commands just freeze console and don’t show stdout content

sudo tail -f /proc/15608/fd/1my console sudo cat /proc/15608/fd/1 

Notice strace works perfectly:

sudo strace -e write=1 -e trace=write -p 15608 

But it gives me too much useless text.

My question: why don’t cat (and tail) work properly and freeze my console? Could somebody explain me why it happens?

HDMI (DP-3) no output 2560×1600 59-60Hz in Ubuntu 19.04

There’s no HDMI (which is DP-3 in xrandr) output on 2560×1600 59Hz or 60Hz in Ubuntu 19.04.
Whether I try it with intel or the nvidia chip, the output is limited to 30Hz. Please note that 2560×1600 with 60Hz is working fine in Windows 10 with the same cable and monitor.

Adding custom modes with xrandr on 60Hz won’t work. Changing configuration won’t work. However things will work as long as I keep the 30Hz setting with the custom xrandr setting.

Notebook: Dell Precision 5530

lspci -kvnn:

00:00.0 Host bridge [0600]: Intel Corporation 8th Gen Core Processor Host Bridge/DRAM Registers [8086:3ec4] (rev 07)     Subsystem: Dell 8th Gen Core Processor Host Bridge/DRAM Registers [1028:087d]     Flags: bus master, fast devsel, latency 0     Capabilities: [e0] Vendor Specific Information: Len=10 <?>     Kernel driver in use: skl_uncore  00:01.0 PCI bridge [0604]: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor PCIe Controller (x16) [8086:1901] (rev 07) (prog-if 00 [Normal decode])     Flags: bus master, fast devsel, latency 0, IRQ 122     Bus: primary=00, secondary=01, subordinate=01, sec-latency=0     I/O behind bridge: 00003000-00003fff     Memory behind bridge: ec000000-ed0fffff     Prefetchable memory behind bridge: 00000000c0000000-00000000d1ffffff     Capabilities: [88] Subsystem: Dell Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor PCIe Controller (x16) [1028:087d]     Capabilities: [80] Power Management version 3     Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [a0] Express Root Port (Slot+), MSI 00     Capabilities: [100] Virtual Channel     Capabilities: [140] Root Complex Link     Capabilities: [d94] #19     Kernel driver in use: pcieport  00:02.0 VGA compatible controller [0300]: Intel Corporation UHD Graphics 630 (Mobile) [8086:3e9b] (prog-if 00 [VGA controller])     Subsystem: Dell UHD Graphics 630 (Mobile) [1028:087d]     Flags: bus master, fast devsel, latency 0, IRQ 158     Memory at eb000000 (64-bit, non-prefetchable) [size=16M]     Memory at 80000000 (64-bit, prefetchable) [size=256M]     I/O ports at 4000 [size=64]     [virtual] Expansion ROM at 000c0000 [disabled] [size=128K]     Capabilities: [40] Vendor Specific Information: Len=0c <?>     Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00     Capabilities: [ac] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [d0] Power Management version 2     Capabilities: [100] Process Address Space ID (PASID)     Capabilities: [200] Address Translation Service (ATS)     Capabilities: [300] Page Request Interface (PRI)     Kernel driver in use: i915     Kernel modules: i915  00:04.0 Signal processing controller [1180]: Intel Corporation Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem [8086:1903] (rev 07)     Subsystem: Dell Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Thermal Subsystem [1028:087d]     Flags: fast devsel, IRQ 16     Memory at ed510000 (64-bit, non-prefetchable) [size=32K]     Capabilities: [90] MSI: Enable- Count=1/1 Maskable- 64bit-     Capabilities: [d0] Power Management version 3     Capabilities: [e0] Vendor Specific Information: Len=0c <?>     Kernel driver in use: proc_thermal     Kernel modules: processor_thermal_device  00:08.0 System peripheral [0880]: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th Gen Core Processor Gaussian Mixture Model [8086:1911]     Subsystem: Dell Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th Gen Core Processor Gaussian Mixture Model [1028:087d]     Flags: fast devsel, IRQ 255     Memory at ed528000 (64-bit, non-prefetchable) [disabled] [size=4K]     Capabilities: [90] MSI: Enable- Count=1/1 Maskable- 64bit-     Capabilities: [dc] Power Management version 2     Capabilities: [f0] PCI Advanced Features  00:12.0 Signal processing controller [1180]: Intel Corporation Cannon Lake PCH Thermal Controller [8086:a379] (rev 10)     Subsystem: Dell Cannon Lake PCH Thermal Controller [1028:087d]     Flags: fast devsel, IRQ 16     Memory at ed527000 (64-bit, non-prefetchable) [size=4K]     Capabilities: [50] Power Management version 3     Capabilities: [80] MSI: Enable- Count=1/1 Maskable- 64bit-     Kernel driver in use: intel_pch_thermal     Kernel modules: intel_pch_thermal  00:14.0 USB controller [0c03]: Intel Corporation Cannon Lake PCH USB 3.1 xHCI Host Controller [8086:a36d] (rev 10) (prog-if 30 [XHCI])     Subsystem: Dell Cannon Lake PCH USB 3.1 xHCI Host Controller [1028:087d]     Flags: bus master, medium devsel, latency 0, IRQ 127     Memory at ed500000 (64-bit, non-prefetchable) [size=64K]     Capabilities: [70] Power Management version 2     Capabilities: [80] MSI: Enable+ Count=1/8 Maskable- 64bit+     Capabilities: [90] Vendor Specific Information: Len=14 <?>     Kernel driver in use: xhci_hcd  00:14.2 RAM memory [0500]: Intel Corporation Cannon Lake PCH Shared SRAM [8086:a36f] (rev 10)     Subsystem: Dell Cannon Lake PCH Shared SRAM [1028:087d]     Flags: fast devsel     Memory at ed51e000 (64-bit, non-prefetchable) [disabled] [size=8K]     Memory at ed526000 (64-bit, non-prefetchable) [disabled] [size=4K]     Capabilities: [80] Power Management version 3  00:15.0 Serial bus controller [0c80]: Intel Corporation Device [8086:a368] (rev 10)     Subsystem: Dell Device [1028:087d]     Flags: bus master, fast devsel, latency 0, IRQ 16     Memory at 7f800000 (64-bit, non-prefetchable) [size=4K]     Capabilities: [80] Power Management version 3     Capabilities: [90] Vendor Specific Information: Len=14 <?>     Kernel driver in use: intel-lpss     Kernel modules: intel_lpss_pci  00:15.1 Serial bus controller [0c80]: Intel Corporation Device [8086:a369] (rev 10)     Subsystem: Dell Device [1028:087d]     Flags: bus master, fast devsel, latency 0, IRQ 17     Memory at 7f801000 (64-bit, non-prefetchable) [size=4K]     Capabilities: [80] Power Management version 3     Capabilities: [90] Vendor Specific Information: Len=14 <?>     Kernel driver in use: intel-lpss     Kernel modules: intel_lpss_pci  00:16.0 Communication controller [0780]: Intel Corporation Cannon Lake PCH HECI Controller [8086:a360] (rev 10)     Subsystem: Dell Cannon Lake PCH HECI Controller [1028:087d]     Flags: bus master, fast devsel, latency 0, IRQ 143     Memory at ed523000 (64-bit, non-prefetchable) [size=4K]     Capabilities: [50] Power Management version 3     Capabilities: [8c] MSI: Enable+ Count=1/1 Maskable- 64bit+     Capabilities: [a4] Vendor Specific Information: Len=14 <?>     Kernel driver in use: mei_me     Kernel modules: mei_me  00:17.0 SATA controller [0106]: Intel Corporation Device [8086:a353] (rev 10) (prog-if 01 [AHCI 1.0])     Subsystem: Dell Device [1028:087d]     Flags: bus master, 66MHz, medium devsel, latency 0, IRQ 129     Memory at ed51c000 (32-bit, non-prefetchable) [size=8K]     Memory at ed522000 (32-bit, non-prefetchable) [size=256]     I/O ports at 4090 [size=8]     I/O ports at 4080 [size=4]     I/O ports at 4060 [size=32]     Memory at ed521000 (32-bit, non-prefetchable) [size=2K]     Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [70] Power Management version 3     Capabilities: [a8] SATA HBA v1.0     Kernel driver in use: ahci     Kernel modules: ahci  00:1b.0 PCI bridge [0604]: Intel Corporation Cannon Lake PCH PCI Express Root Port [8086:a340] (rev f0) (prog-if 00 [Normal decode])     Flags: bus master, fast devsel, latency 0, IRQ 123     Bus: primary=00, secondary=02, subordinate=3a, sec-latency=0     I/O behind bridge: 00005000-00007fff     Memory behind bridge: d4000000-ea0fffff     Prefetchable memory behind bridge: 0000000090000000-00000000b1ffffff     Capabilities: [40] Express Root Port (Slot+), MSI 00     Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [90] Subsystem: Dell Cannon Lake PCH PCI Express Root Port [1028:087d]     Capabilities: [a0] Power Management version 3     Capabilities: [100] Advanced Error Reporting     Capabilities: [140] Access Control Services     Capabilities: [150] Precision Time Measurement     Capabilities: [220] #19     Capabilities: [250] Downstream Port Containment     Kernel driver in use: pcieport  00:1c.0 PCI bridge [0604]: Intel Corporation Cannon Lake PCH PCI Express Root Port [8086:a338] (rev f0) (prog-if 00 [Normal decode])     Flags: bus master, fast devsel, latency 0, IRQ 124     Bus: primary=00, secondary=3b, subordinate=3b, sec-latency=0     Memory behind bridge: ed400000-ed4fffff     Capabilities: [40] Express Root Port (Slot+), MSI 00     Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [90] Subsystem: Dell Cannon Lake PCH PCI Express Root Port [1028:087d]     Capabilities: [a0] Power Management version 3     Capabilities: [100] Advanced Error Reporting     Capabilities: [140] Access Control Services     Capabilities: [150] Precision Time Measurement     Capabilities: [200] L1 PM Substates     Capabilities: [220] #19     Capabilities: [250] Downstream Port Containment     Kernel driver in use: pcieport  00:1c.4 PCI bridge [0604]: Intel Corporation Cannon Lake PCH PCI Express Root Port [8086:a33c] (rev f0) (prog-if 00 [Normal decode])     Flags: bus master, fast devsel, latency 0, IRQ 125     Bus: primary=00, secondary=3c, subordinate=3c, sec-latency=0     Memory behind bridge: ed300000-ed3fffff     Capabilities: [40] Express Root Port (Slot+), MSI 00     Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [90] Subsystem: Dell Cannon Lake PCH PCI Express Root Port [1028:087d]     Capabilities: [a0] Power Management version 3     Capabilities: [100] Advanced Error Reporting     Capabilities: [140] Access Control Services     Capabilities: [150] Precision Time Measurement     Capabilities: [200] L1 PM Substates     Capabilities: [220] #19     Capabilities: [250] Downstream Port Containment     Kernel driver in use: pcieport  00:1d.0 PCI bridge [0604]: Intel Corporation Cannon Lake PCH PCI Express Root Port 9 [8086:a330] (rev f0) (prog-if 00 [Normal decode])     Flags: bus master, fast devsel, latency 0, IRQ 126     Bus: primary=00, secondary=3d, subordinate=3d, sec-latency=0     Memory behind bridge: ed200000-ed2fffff     Capabilities: [40] Express Root Port (Slot+), MSI 00     Capabilities: [80] MSI: Enable+ Count=1/1 Maskable- 64bit-     Capabilities: [90] Subsystem: Dell Cannon Lake PCH PCI Express Root Port [1028:087d]     Capabilities: [a0] Power Management version 3     Capabilities: [100] Advanced Error Reporting     Capabilities: [140] Access Control Services     Capabilities: [150] Precision Time Measurement     Capabilities: [200] L1 PM Substates     Capabilities: [220] #19     Capabilities: [250] Downstream Port Containment     Kernel driver in use: pcieport  00:1f.0 ISA bridge [0601]: Intel Corporation Device [8086:a30e] (rev 10)     Subsystem: Dell Device [1028:087d]     Flags: bus master, fast devsel, latency 0  00:1f.3 Audio device [0403]: Intel Corporation Cannon Lake PCH cAVS [8086:a348] (rev 10) (prog-if 80)     Subsystem: Dell Cannon Lake PCH cAVS [1028:087d]     Flags: bus master, fast devsel, latency 32, IRQ 159     Memory at ed518000 (64-bit, non-prefetchable) [size=16K]     Memory at ed100000 (64-bit, non-prefetchable) [size=1M]     Capabilities: [50] Power Management version 3     Capabilities: [80] Vendor Specific Information: Len=14 <?>     Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+     Kernel driver in use: snd_hda_intel     Kernel modules: snd_hda_intel, snd_soc_skl  00:1f.4 SMBus [0c05]: Intel Corporation Cannon Lake PCH SMBus Controller [8086:a323] (rev 10)     Subsystem: Dell Cannon Lake PCH SMBus Controller [1028:087d]     Flags: medium devsel, IRQ 16     Memory at ed520000 (64-bit, non-prefetchable) [size=256]     I/O ports at efa0 [size=32]     Kernel driver in use: i801_smbus     Kernel modules: i2c_i801  00:1f.5 Serial bus controller [0c80]: Intel Corporation Cannon Lake PCH SPI Controller [8086:a324] (rev 10)     Subsystem: Dell Cannon Lake PCH SPI Controller [1028:087d]     Flags: fast devsel     Memory at fe010000 (32-bit, non-prefetchable) [size=4K]  01:00.0 3D controller [0302]: NVIDIA Corporation GP107GLM [Quadro P1000 Mobile] [10de:1cbb] (rev a1)     Flags: bus master, fast devsel, latency 0, IRQ 255     Memory at ec000000 (32-bit, non-prefetchable) [size=16M]     Memory at c0000000 (64-bit, prefetchable) [size=256M]     Memory at d0000000 (64-bit, prefetchable) [size=32M]     I/O ports at 3000 [disabled] [size=128]     [virtual] Expansion ROM at ed000000 [disabled] [size=512K]     Capabilities: [60] Power Management version 3     Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+     Capabilities: [78] Express Endpoint, MSI 00     Capabilities: [100] Virtual Channel     Capabilities: [250] Latency Tolerance Reporting     Capabilities: [258] L1 PM Substates     Capabilities: [128] Power Budgeting <?>     Capabilities: [420] Advanced Error Reporting     Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024 <?>     Capabilities: [900] #19     Kernel modules: nvidiafb, nouveau, nvidia_drm, nvidia  3b:00.0 Network controller [0280]: Intel Corporation Wireless-AC 9260 [8086:2526] (rev 29)     Subsystem: Intel Corporation Wireless-AC 9260 [8086:4010]     Flags: bus master, fast devsel, latency 0, IRQ 16     Memory at ed400000 (64-bit, non-prefetchable) [size=16K]     Capabilities: [c8] Power Management version 3     Capabilities: [d0] MSI: Enable- Count=1/1 Maskable- 64bit+     Capabilities: [40] Express Endpoint, MSI 00     Capabilities: [80] MSI-X: Enable+ Count=16 Masked-     Capabilities: [100] Advanced Error Reporting     Capabilities: [14c] Latency Tolerance Reporting     Capabilities: [154] L1 PM Substates     Kernel driver in use: iwlwifi     Kernel modules: iwlwifi  3c:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader [10ec:525a] (rev 01)     Subsystem: Dell RTS525A PCI Express Card Reader [1028:087d]     Flags: bus master, fast devsel, latency 0, IRQ 128     Memory at ed300000 (32-bit, non-prefetchable) [size=4K]     Capabilities: [80] Power Management version 3     Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit+     Capabilities: [b0] Express Endpoint, MSI 00     Capabilities: [100] Advanced Error Reporting     Capabilities: [148] Device Serial Number 00-00-00-01-00-4c-e0-00     Capabilities: [158] Latency Tolerance Reporting     Capabilities: [160] L1 PM Substates     Kernel driver in use: rtsx_pci     Kernel modules: rtsx_pci  3d:00.0 Non-Volatile memory controller [0108]: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981 [144d:a808] (prog-if 02 [NVM Express])     Subsystem: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981 [144d:a801]     Flags: bus master, fast devsel, latency 0, IRQ 16, NUMA node 0     Memory at ed200000 (64-bit, non-prefetchable) [size=16K]     Capabilities: [40] Power Management version 3     Capabilities: [50] MSI: Enable- Count=1/32 Maskable- 64bit+     Capabilities: [70] Express Endpoint, MSI 00     Capabilities: [b0] MSI-X: Enable+ Count=33 Masked-     Capabilities: [100] Advanced Error Reporting     Capabilities: [148] Device Serial Number 00-00-00-00-00-00-00-00     Capabilities: [158] Power Budgeting <?>     Capabilities: [168] #19     Capabilities: [188] Latency Tolerance Reporting     Capabilities: [190] L1 PM Substates     Kernel driver in use: nvme     Kernel modules: nvme 

xrandr:

Screen 0: minimum 320 x 200, current 4480 x 1600, maximum 8192 x 8192 eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 344mm x 194mm    1920x1080     60.00*+  59.97    59.96    59.93      1680x1050     59.95    59.88      1600x1024     60.17      1400x1050     59.98      1600x900      59.99    59.94    59.95    59.82      1280x1024     60.02      1440x900      59.89      1400x900      59.96    59.88      1280x960      60.00      1440x810      60.00    59.97      1368x768      59.88    59.85      1360x768      59.80    59.96      1280x800      59.99    59.97    59.81    59.91      1152x864      60.00      1280x720      60.00    59.99    59.86    59.74      1024x768      60.04    60.00      960x720       60.00      928x696       60.05      896x672       60.01      1024x576      59.95    59.96    59.90    59.82      960x600       59.93    60.00      960x540       59.96    59.99    59.63    59.82      800x600       60.00    60.32    56.25      840x525       60.01    59.88      864x486       59.92    59.57      800x512       60.17      700x525       59.98      800x450       59.95    59.82      640x512       60.02      720x450       59.89      700x450       59.96    59.88      640x480       60.00    59.94      720x405       59.51    58.99      684x384       59.88    59.85      680x384       59.80    59.96      640x400       59.88    59.98      576x432       60.06      640x360       59.86    59.83    59.84    59.32      512x384       60.00      512x288       60.00    59.92      480x270       59.63    59.82      400x300       60.32    56.34      432x243       59.92    59.57      320x240       60.05      360x202       59.51    59.13      320x180       59.84    59.32   DP-1 disconnected (normal left inverted right x axis y axis) DP-2 disconnected (normal left inverted right x axis y axis) DP-3 connected 2560x1600+1920+0 (normal left inverted right x axis y axis) 641mm x 401mm    2560x1600     59.97*+    2048x1280     60.20      1920x1200     59.95      2048x1080     24.00      1920x1080     60.00    60.00    50.00    59.94    24.00    23.98      1920x1080i    60.00    50.00    59.94      1600x1200     60.00      1680x1050     59.88      1280x1024     75.02    60.02      1280x800      59.91      1152x864      75.00      1280x720      60.00    60.00    50.00    59.94      1024x768      75.03    60.00      800x600       75.00    60.32      720x576       50.00    50.00      720x480       60.00    60.00    59.94    59.94      640x480       75.00    60.00    59.94    59.94      720x400       70.08   

Please help with this issue, or please help me file a bug with this. This should work out of the box.

Wrong output with OPEdefs

I learn how to use the package OPEdefs.m to compute the OPEs in Mathematica. I practiced some commands along the manual (DOI: 10.1142/S0129183191001001). In section 3, explicit examples for a Kac-Moody algebra are given. After loading the package, I tried as written in the manual

Bosonic[J[i_]] Fermionic[psi[i_]] 

as well as

OPE[J[i_],J[i_]][z_, w_]:= -k/2 (z - w)^-2 + Ord[z,w,0] OPE[J[1], J[2]][z_, w_] := J[3][w] (z - w)^-1 + Ord[z, w, 0] OPE[J[2], J[3]][z_, w_] := J[1][w] (z - w)^-1 + Ord[z, w, 0] OPE[J[1], J[3]][z_, w_] := -J[2][w] (z - w)^-1 + Ord[z, w, 0] 

Then I defined the stress-tensor as

T = -1/(k + 2) (NO[J[1], J[1]] + NO[J[2], J[2]] + NO[J[3], J[3]]); 

to compute

Simplify[OPE[T, J[1]][z, w]] 

So far everything goes along the manual. However, the output was

-J[2][w]/(z-w) + O[z-w]^0 

different from the right result:

J[1][w](-w+z)^-2 + (J[1]')[w](-w+z)^-1 + O[-w+z]^0 

Seemingly, the OPE between J[1] and J[3] is wrongly output. I also tested

OPE[J[1], J[2]][z, w] 

, but even its output was -J[2][w]/(z-w) + O[z-w]^0. I have no idea of what goes wrong.

The version of my Mathematica is 11.3.

How do I select a USB drive folder for an application output?

I’m attempting to install a new app on an Ubuntu 18.04 system. I want to redirect the files outputted to a USB drive, rather than on my SSD.

eg:

 /var/snap/sabnzbd/common/Downloads/incomplete 

to

 31 gb /Downloads/incomplete   

(where 31 GB) is the ubuntu assigned name of the USB drive.

I KNOW this MUST be awfully silly sounding question, but I am a TOTAL nube

I am looking for an algorithm that can find the best possible combination of inputs, in order to determine the optimum output

So as the title poorly implies, I’m looking for an algorithm that can accomplish the following task (as an example):

Given the inputs A(1:100), B(1:100), C(1:100), that can take on any value between 1 to 100.

Given the outputs X, Y, Z, which are determined by a combination of the inputs eg:

A=2, B=3,C=4, returns X=76, Y=87, Z=34

A=5,B=1,C=100 returns X=52, Y=45, Z=24 etc.

The problem is, I have no clue how the inputs affect the outputs and so id like to find an algorithm of some sort that can try out various combinations of inputs in a logical manner (not randomly) to find the optimal output or get as close as possible to said optimum output, which in my case is finding the highest possible valued combination of X,Y,Z so best case scenario is finding a set of inputs that return 100, 100, 100 as the XYZ values.

If anyone has any idea how I could approach this or if a question like this has already been answered, I appreciate any and all help.

Thank you!