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by jamesh
Tue Oct 16, 2018 3:27 pm
Forum: C/C++
Topic: I am missing some fundamental understanding of C?
Replies: 12
Views: 184

Re: I am missing some fundamental understanding of C?

Where are the variables used in the image function declared? I wonder if you have two sets defined, and its using uninitialised ones. You'll probably need to provide the entire functions to be clearer.
by jamesh
Tue Oct 16, 2018 3:18 pm
Forum: Python
Topic: Speed of indexing vs looping
Replies: 9
Views: 165

Re: Speed of indexing vs looping

But again, that very inefficient. You are creating an entirely new string, one character at a time. All you want to do is compare. ... or something. Which will also be inefficient, creating two single character strings as it goes. That's all Python allows for. Underneath the hood it's different. Bu...
by jamesh
Tue Oct 16, 2018 2:19 pm
Forum: Python
Topic: Speed of indexing vs looping
Replies: 9
Views: 165

Re: Speed of indexing vs looping

Your loop version is very inefficient. You created an entirety new string, add a load of characters to it, then compare, all of which are lengthy processes. All you need to do is loop for half the string, and compare characters from the front+index to the back-index. Thanks for the reply. You're ri...
by jamesh
Tue Oct 16, 2018 2:14 pm
Forum: Raspbian
Topic: vcgencmd get_throttled
Replies: 3
Views: 138

Re: vcgencmd get_throttled

There a vcgencmd doc I've been working on that has the full table, see here

https://github.com/raspberrypi/document ... cgencmd.md
by jamesh
Tue Oct 16, 2018 1:52 pm
Forum: Raspbian
Topic: vcgencmd get_throttled
Replies: 3
Views: 138

Re: vcgencmd get_throttled

Yes, that new bit is the SOFT_TEMP_LIMIT bit.

0x80000 means its has been set in the past, 0x8 means it is set at the moment (ie happening)
by jamesh
Tue Oct 16, 2018 1:42 pm
Forum: Raspbian
Topic: Is it Time to force Raspbian password change on initial login
Replies: 39
Views: 1027

Re: Is it Time to force Raspbian password change on initial login

So, had a chat. Consensus is that we are generally happy with the middle of the road approach we have right now whereby running Raspiconfig prompts you to enter a new password. This gives up a happy medium between security, and the needs of the classroom, where you don't want to be spending half the...
by jamesh
Tue Oct 16, 2018 10:03 am
Forum: General discussion
Topic: HID multitouch implementation.
Replies: 3
Views: 95

Re: HID multitouch implementation.

Not really enogh information to make any suggestions.What make is the HID etc would help for starters.
by jamesh
Tue Oct 16, 2018 10:00 am
Forum: Mathematica
Topic: Matematica removed from raspbian image
Replies: 29
Views: 1473

Re: Matematica removed from raspbian image

Oh, it is back, what a good surprise after a bad surprise. Thank you! So I guess no need to sack anyone then (even if møøse bites Kan be pretti nasti :-)) Also there is now 'Download installation script now' button at http://www.wolfram.com/raspberry-pi/ which is shell script that gets wolfram-engi...
by jamesh
Tue Oct 16, 2018 9:54 am
Forum: Python
Topic: Speed of indexing vs looping
Replies: 9
Views: 165

Re: Speed of indexing vs looping

But again, that very inefficient. You are creating an entirely new string, one character at a time. All you want to do is compare.

Pseudocode

Code: Select all

len = length of string
for c = 0 to len/2
   if (string[c] != string[len -c])
      not a palindrome
or something.
by jamesh
Tue Oct 16, 2018 7:38 am
Forum: Python
Topic: Speed of indexing vs looping
Replies: 9
Views: 165

Re: Speed of indexing vs looping

Your loop version is very inefficient. You created an entirety new string, add a load of characters to it, then compare, all of which are lengthy processes.

All you need to do is loop for half the string, and compare characters from the front+index to the back-index.
by jamesh
Tue Oct 16, 2018 7:33 am
Forum: Raspbian
Topic: Is it Time to force Raspbian password change on initial login
Replies: 39
Views: 1027

Re: Is it Time to force Raspbian password change on initial login

Enough I think. I'll have a chat in office to see what people think on this subject.
by jamesh
Mon Oct 15, 2018 5:07 pm
Forum: Other projects
Topic: Raspberry Pi Display Screen with Touchscreen Control Panel
Replies: 2
Views: 93

Re: Raspberry Pi Display Screen with Touchscreen Control Panel

Might be worth reading this thread, where support for HDMI and LCD at the same time is discussed/introduced.

https://www.raspberrypi.org/forums/view ... 3&t=216399
by jamesh
Mon Oct 15, 2018 7:46 am
Forum: General discussion
Topic: Multiple Frame buffer beta testers wanted
Replies: 223
Views: 8936

Re: Multiple Frame buffer beta testers wanted

aBUGSworstnightmare wrote:
Mon Oct 15, 2018 7:41 am
Hi jamesh,

did any of the multiple framebuffer code made it into latest Raspbian release (2018-10-09)? If not, can you prepare files to test with latest version?
None of the code has been merged yet, I'll need to rebuild everything on the latest tree. Might be able to do in a few days.
by jamesh
Sun Oct 14, 2018 11:55 am
Forum: Advanced users
Topic: Moving Linux kernel to 4.14
Replies: 150
Views: 52359

Re: Moving Linux kernel to 4.14

Hmm, another checksum issue. There are a couple of github issues that may be relevant.
by jamesh
Sun Oct 14, 2018 11:52 am
Forum: General discussion
Topic: New version of Raspbian
Replies: 15
Views: 880

Re: New version of Raspbian

Those images will have Mathematica stripped out. Will those actually replace the old images or will the old images be removed and new 'without Mathematica' reproductions be added ? I can see all sorts of problems looming if what is downloaded in the future isn't the same as what was downloaded and ...
by jamesh
Sat Oct 13, 2018 3:31 pm
Forum: General discussion
Topic: Raspbian or what ? ( semi rant)
Replies: 18
Views: 774

Re: Raspian or what ? ( semi rant)

OK, i'll say it again. This post was not met to be "issue solving" post. I know better. ( Alternate OS suggestions are welcome ) However, when one does "update /upgrade" and then has no means to access internet afterwords how can you say " you need better power supply"? I wish somebody made a list ...
by jamesh
Sat Oct 13, 2018 1:35 pm
Forum: Raspbian
Topic: [Unofficial announcement] Raspbian - October 2018 version
Replies: 17
Views: 939

Re: [Unofficial announcement] Raspbian - October 2018 version

Weather is the thing us Brits talk about when there's nothing much else going on in the world. Here in Oregon we say there are only 2 seasons... ... rainy and construction. A quick google search says we get much more rain here in Portland, Oregon than London in the UK (roughly double at 43 inches, ...
by jamesh
Sat Oct 13, 2018 1:33 pm
Forum: General discussion
Topic: New version of Raspbian
Replies: 15
Views: 880

Re: New version of Raspbian

I suppose if an empty package was created with the same name as the existing one, and a later version number, it could replace the genuine package on a straight upgrade That would probably get the Pi and Foundation a fair amount of publicity with quite a lot of it not positive nor good. It seems th...
by jamesh
Sat Oct 13, 2018 7:04 am
Forum: Add-ons
Topic: PoE HAT - USB Ports not working - over-current
Replies: 208
Views: 16064

Re: PoE HAT - USB Ports not working - over-current

Bought mine from sos solutions. But fortunately could return it without problem. I did mail them and pointed them to this thread but got no response. Strange thing is, the PEO hat did work without problem before updating the PI. But as the fan didn't work I did update the software. With the latest ...
by jamesh
Sat Oct 13, 2018 6:55 am
Forum: Bare metal, Assembly language
Topic: FT5406 Touch coordinate corruption
Replies: 25
Views: 623

Re: FT5406 Touch coordinate corruption

Circle is using the original algorithm for detecting touch screen events from the Linux driver. There has been an update to the Linux driver later, which fixes a spurious event issue from the touch screen. This fix has not been applied to the Circle driver yet. I will check this soon. I did some te...
by jamesh
Sat Oct 13, 2018 6:53 am
Forum: Troubleshooting
Topic: Diagonal flashing when screen refreshes or images displayed in browser
Replies: 3
Views: 90

Re: Diagonal flashing when screen refreshes or images displayed in browser

This is tearing caused by the rotate. Use the extra_transpose_buffer option in config.txt to improve this.
by jamesh
Sat Oct 13, 2018 6:48 am
Forum: Mathematica
Topic: Matematica removed from raspbian image
Replies: 29
Views: 1473

Re: Matematica removed from raspbian image

Indeed. It always amazes me how virulent some poeople can be about what is, in effect, a charity project aimed at teaching children. Yes, things have broadended out to cover a lot more than education, but education is where all the money goes. In recent years I have recommended the Pi to students a...
by jamesh
Fri Oct 12, 2018 3:50 pm
Forum: Bare metal, Assembly language
Topic: FT5406 Touch coordinate corruption
Replies: 25
Views: 623

Re: FT5406 Touch coordinate corruption

IIRC, all the firmware does is pass on the data it get from the touchscreen. No real processing done on it.
by jamesh
Fri Oct 12, 2018 3:49 pm
Forum: General discussion
Topic: Raspbian or what ? ( semi rant)
Replies: 18
Views: 774

Re: Raspian or what ? ( semi rant)

OK, i'll say it again. This post was not met to be "issue solving" post. I know better. ( Alternate OS suggestions are welcome ) However, when one does "update /upgrade" and then has no means to access internet afterwords how can you say " you need better power supply"? I wish somebody made a list ...

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