Saturn and Titan Version 4.0.0 Release Delayed   Leave a comment


The release of the new versions of Saturn and Titan is delayed due to two issues, performance and my iMac 24″ (2008).

Here is an example picture to illustrate the performance issue:

Lyapunov 24

Lyapunov 24

While testing the new versions of Saturn I had been comparing completion times with version 3.0.1, which generally showed an improvement. There were some cases where there was no improvement and by the time Saturn and Titan 4.0.0 is ready to be released there will probably still be some cases where version 3.0.1 is still better. Out of interest I tried version 2.1.4 and discovered that it was much faster than version 3.0.1 and what will be version 4.0.0. The seed file (750×500) for the picture above took longer using version 4.0.0 than versions 3.0.1 and 2.1.4. Since version 3.0.0 there have been two calculation modes, “progressive” and “row-by-row” prior to that there was only progressive, the times (in seconds) for version 4.0.0 were about 95 (progressive) and 25 (row-by-row), for version 3.0.1 they were 90 and 35, finally the time for version 2.1.4 was 75. The times were obtained under heavy load i.e. 100% CPU usage, two long timescale runs (one of Saturn, one of Titan) were in progress, the CPU is a quad core i7 running at 3.4GHz and the operating system is Linux Mint 14.

For the default Mandelbrot with dimensions 750 by 500 I went back further, the following times were obtained by allowing Saturn as much CPU time as possible:

Saturn version progressive row-by-row
1.0.2 23.7 n/a
1.1 23.6 n/a
2.0.1 7.6 n/a
2.1.4 7.5 n/a
3.0.1 9.2 3.5
4.0.0 beta 12.7 1.9

Comparing the times on Windows and OS X were worse, OS X especially so. Clearly performance had to be addressed before releasing the new version. It has taken a while but on Linux performance has been improved.

For Lyapunov 24, under the same conditions as before:

Saturn version progressive row-by-row
3.0.1 93.7 35.5
4.0.0 beta 58.9 24.9

For the default Mandelbrot, 5000 iterations, 750×500 and the same conditions as Lyapunov 24:

Saturn version progressive row-by-row
3.0.1 38.1 13.7
4.0.0 beta 24.9 6.0

I was ready to try out the changes I made to Saturn on OS X and Windows, but before I could my iMac became relatively useless. The only way I have of preparing the Windows 7 version of Saturn and Titan is by way of a virtual machine running Windows 7 hosted by OS X, so the problem with the iMac currently prevents me from progressing with both the Window 7 and the OS X version.

A couple of day ago the iMac locked up and a few minutes later rebooted itself and then part way through booting OS X it displayed “You must restart your computer”. Not good. My iMac is set up to dual boot OS X and Linux. I tried booting from the various installation media, OS X Leopard and Snow Leopard discs and an OS X Lion USB stick, booting from either of the installation discs failed as part way through the boot process the aforementioned message was displayed, when booting from the USB stick it boots into Linux instead. Booting into Linux fails due to X windows not successfully running, the appearance of the screen varies depending on whether I boot the installed Linux or from a Linux installation dis, one of following happens: a grey screen a small black box, random coloured blocks or an image corrupted by thick horizontal lines. At one point a Linux boot breifly abandoned trying to run X windows and displayed a message about a faulty GPU before having an other go at running X windows. Later on booting from Linux installation discs just displayed a cursor in the top left hand corner.

Unfortunately the subversion repository for Saturn and Titan was in a Linux virtual machine hosted by OS X on the iMac and the backups for that and some other files are a little out of date. At was not lost however: disabling X windows on Linux allowed me to boot Linux to the command line and I copied all the files I needed onto an external disc. The VMware virtual machine containing Linux was easily converted to a VirtualBox virtual machine running on Linux so I now have access to the subversion repository, no such luck with the Windows, when the converted virtal machine is run it briefly produces the well known “blue screen of death” and then it states that Windows can’t boot and needs to repair and on completion of that process says it can’t boot and needs to be repaired. I suspect the VMware Windows virtual machine is OK provided it is run by VMware Fusion, which I only have on OS X.

To continue with Windows 7 I have to start afresh with a new install and then I need to find and install all the development tools I used to create a Windows installer for Saturn and Titan. For OS X the options are either repair or replace the iMac.

I haven’t lost anything in regard to development of Saturn and Titan except time. The release of Saturn and Titan version 4.0.0 is delayed and I’ve no idea how long that will be.

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Posted 12 July 2013 by element90 in Development, Software

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