I have tick label values which I want to multiply by 1000 (data is in W - I want to plot mW) so I set the divide by factor to 0.001. This appears to work at first, but eventually, after opening the dialog again, the label values seem to acquire some sort of rounding error and display as (eg.) 5.000000237 rather than 5.

Obviously I can just create another data set where the original values are multiplied by 1000, but it would be far more straight forward to get this function to work properly. Any suggestions?

Ian,

I am able to reproduce the problem as you had stated in your well-detailed example. However, one thing you failed to mention is whether or not I was to set the decimal places. I assumed this to be the case so I did. As I have stated in the previous response, the round-off error seems to be occurring due to the order in which I perform the steps. I found that if I did all of the following within the dialog box (in one step in other words) without clicking OK or Apply, I received the correct decimal values:

- Enter a divide by value
- Enter a value of 9 for Set Decimal Places
- On the Custom Tick Labels tab, enter a value of 30 for rotation so that I can see all the labels.
- Click OK

In this case, the values do not show round-off errors. However, if I OK out of the dialog box before remembering to enter a value for the Set Decimal Places, and then go back in to do so, I get the error.

Unfortunately there isn't much else I can say other than that you should try performing the steps in one instance of the dialog box (or in a different order of steps). Otherwise the round-off error is sure to occur.

I have asked a senior engineer if something like this should be considered a bug, but he has said to me that this problem is inherent in all software, including Origin.

Let me know if you are able to achieve success.

Sincerely,
Ryan Toomey
Technical Support engineer
Microcal Software

[This message has been edited by rtoomey (edited 11-03-98).]

I'm afraid it doesn't really deal with my problem as I seem to get this effect without changing the increment value at all. Try this and see what happens:

Open a new project

Set column values for col(a) to i/1000 for rows 1 to 100.

Set column values for col(b) to col(a)^2 for rows 1 to 100.

Select col(b) and plot as a line.

This should give you x-axis values ranging from 0 to 0.1 and y values from 0 to 0.01.

Double click on the x-axis to bring up the dialog, go to the tick-labels tab and set the divide by factor to 0.001 and click OK.

This should now give you an x-axis scale from 0 to 100 - all well and good....

Now, double click on the x-axis to bring up the dialog again. Don't change ANYTHING - just click OK to close the dialog.

At this stage I now see the error I described. The same error can be induced by clicking apply after setting the divide by factor then clicking OK to close the dialog. It can also be produced on the y-axis in a similar manner. It seems that after setting the divide by factor any subsequent use of the axis dialog causes the error to occur.

I've reproduced this error on three different machines: a 100MHz 486 running Windows95, a 233MHz AMD K6 running Windows95, and a 400MHz PII running Windows 98.

Hope this is of use.

I'd forgotten about the set decimal places check box (despite the fact that it's directly below the divide by factor - a classic case of not seeing the wood for the trees)! This seems to be the best solution to this problem as even if I cause the error to occur I can cover it up by setting decimal places to 0,1 or whatever.

Thanks again,