Would anyone know if there is a way to define a variable or a function that increases in value by 1 every time it is called?

I am trying to set up automatic naming scheme for the image output of my excel_PNG plugin. It takes a filepath as an input to be used when saving generated png. What i need is to generate the filepath string which is different every time its called. It also needs to be consistent (i.e it cannot change for a particular function call every time worksheet is calculated) so random() will not work.

Ideas? Unique consistency of the value for a certain position within workbook is s the goal.

Here what i tried, predictably without success.



ID.sm (4kb) downloaded 15 time(s).

Edited by user 24 February 2016 21:42:59(UTC)  | Reason: Not specified

Thank you, Ioan, this might be my best bet. Not ideal though because it does require my input; I have about 100 calls to excel_PNG in one file, each of the call generates a PNG file, and it can be cumbersome to change the id variable for each of them.

So i take there is no "counter" function in SMath is there?

Hello Alex

You can try this: Alex4.sm (12kb) downloaded 27 time(s).

findstr(...) is because IsDefined() doesn't work as I expect inside the function, not sure if is a bug or something else.

Edited by user 25 February 2016 01:05:28(UTC)  | Reason: Not specified

Works great, thank you very much! I almost thought it is not possible hehe.

Now I do not quite get how the if() loop works, and why does it work, and why it shall not be equal to -1. Could you walk me through this line of code, explaining what it does exactly?

findstr(num2str(id+1),"+"≠-1

Thanks again, this is very clever and elegant!

Jean, if you can tell me exactly what you do not understand about what I would like to do I will gladly explain it ( I did not quite get it from your post)

From Ioan & Davide, it's OK to view image in Smath, but useless as you can't
further process/select ... etc. You can "fmap vectorise", scale the grayscale
but can't scale RGB replot because Smath does not have the "Picture operator".

Jean

I understand your point of storing dead stuff...
Smath is live for Engineering/Edu/Sciemtific ...





What's the point to read that dead image if the construction is not exemplified ?
There was a long thread on that one, particularly about not a "parrot plot"...
Maybe not yet finished ! ? I admit, humbly, I'm not a "bright spark".

Jean

You're welcome

The function uses pass-by-reference to output the value to the canvas via the input argument.
If the input value is an unknown, will be set to 1. This should be done in the if/else statement using the built-in ¬IsDefined(id) that for some reason I have to investigate doesn't works, so I've replaced it with findstr(num2str(id+1),"+")≠-1
num2str(id+1) converts the input in a math string -> id+1 will be converted in a number and then in a string if the input argument is a number, otherwise will be "something+1" where something is the name of the input unknown in the canvas (because id is a local name that contains the variable passed from the canvas -> a simple num2str(id)≡"id" is not possible); in the first case, findstr will returns -1, because the string contains a number, in the second case will returns a vector that contains the index of each "+" match. Hence if findstr(...)≠-1 -> the variable is not a number, set it to 1, otherwise increment by one.



Jean, I think that both the purposes are OK and can/must coexist

If one needs only to show an image on the canvas, there's no need to fill the worksheet memory or the file itself of useless data.

If one want/needs to process images, this is another story (BTW, many thanks for all the worksheets you share here in the forum )
IMHO as it is now processing images on the worksheet is reliable only for small images (only teaching purposes); using plugins you can boost the math speed or build a region that can do all "in-place" but this is not funny because the math is hidden under the hood. A "picture operator" or a boost in matrices management is needed and can be done only by Andrey (here we are focusing on images but the issue may be the same in any signal processing problem, such as audio, wind, etc...).

The example below is ok for a 128x128 image, but too slow for a 256x256 image (or bigger), using greyscale images, and functions driven in plugin: fftmagnitude (abs() extended to matrices), fftphase (arg() extended to matrices), fftlog (basically a logarithm function for matrices); to run all except the ffts in the canvas (in a reasonable time) 128x128 is too big.

Edited by user 25 February 2016 18:18:37(UTC)  | Reason: Not specified

Maybe, not yet from my side... about the displaying issues I've made a request in the BTS recently (SS-2291)

You can test performances with this simple function: mlog.sm (4kb) downloaded 16 time(s).
Try to change the size of the identity matrix, a 128x128 makes the function sooooooo slow...

Edited by user 25 February 2016 18:40:17(UTC)  | Reason: Not specified

Andrey, this is incredible!

If you can make matricies fly (both calcs and UI / scrolling lag) its a huge-huge plus; this will opens doors to do "real" structural analysis, signal processing, image manipulations... Our digital world is made of matricies!

Thank you very much

Alex M.

Edited by user 26 February 2016 00:11:33(UTC)  | Reason: Not specified