Axis Breakpoint Considered Interpolation

[RyanG]

Any chance the interpolation feature could take into account the axis breakpoint so that it's linear? Given the lower table resolution compared to some other ecu's (arguments to whether needed or not, I'm sure) often axis breakpoints aren't evenly spaced.

I've attached an exaggerated example. Please let me know of any downsides with what I've suggested?

Ryan

[Electredge]

On 3/22/2023 at 9:04 PM, RyanG said:

Any chance the interpolation feature could take into account the axis breakpoint so that it's linear? Given the lower table resolution compared to some other ecu's (arguments to whether needed or not, I'm sure) often axis breakpoints aren't evenly spaced.

I've attached an exaggerated example. Please let me know of any downsides with what I've suggested?

Ryan

are you wanting to be able to use interpolate in the axis setup window?

[RyanG]

12 minutes ago, Electredge said:

are you wanting to be able to use interpolate in the axis setup window?

No, I want to interpolate between cells on the fuel/ignition table, but I want it to do it linearly and with respect to the break-points in the axis between them.

I wish I could post images, but I have no kB left.

With a MoTeC M1 if you interpolate between 50kpa and 80kpa, with 60kpa between:
50kpa: 50% VE
60kpa: X% VE
80kpa: 60% VE

You will get X = 53.3% VE. If you do the same on Link G4X, you get 55% VE. It doesn't make any sense?

[Electredge]

1 hour ago, RyanG said:

No, I want to interpolate between cells on the fuel/ignition table, but I want it to do it linearly and with respect to the break-points in the axis between them.

I wish I could post images, but I have no kB left.

With a MoTeC M1 if you interpolate between 50kpa and 80kpa, with 60kpa between:
50kpa: 50% VE
60kpa: X% VE
80kpa: 60% VE

You will get X = 53.3% VE. If you do the same on Link G4X, you get 55% VE. It doesn't make any sense?

I see what your saying, interesting... I never even noticed m1 was doing that. I see how it would be helpful when the axis is MAP but I think it would be less helpful tuning via alpha n with tps as the axis, since you usually need big jumps in VE over very small throttle changes down low. 

[RyanG]

Any thoughts on this one @Adamw @Vaughan?

[Adamw]

Not quite sure I understand the point.  The whole idea of definable breakpoints is to allow for non linear relationships.  I dont see why you would want to convert it back into a linear interpolation?

On 4/13/2023 at 4:36 PM, RyanG said:

With a MoTeC M1 if you interpolate between 50kpa and 80kpa, with 60kpa between:
50kpa: 50% VE
60kpa: X% VE
80kpa: 60% VE

You will get X = 53.3% VE. If you do the same on Link G4X, you get 55% VE. It doesn't make any sense?

If it does that then there is no point in even having the breakpoints in between the spans of the interpolation, you would get the same result by deleting all rows columns in between.  

 

[RyanG]

1 hour ago, Adamw said:

If it does that then there is no point in even having the breakpoints in between the spans of the interpolation, you would get the same result by deleting all rows columns in between. 

Then what's the purpose of the current interpolate function? In what situation would it be preferable for it to interpolate, but not consider the breakpoints and create a jagged line in a map? If you've tuned 50kpa and 80kpa, and want to interpolate because you think it will be close to linear between those regions, why should the interpolation be non-linear between those points if you have uneven axis breakpoints? Yes this has the same effect as deleting the row/column, but it's just to get it in the ballpark until you tune those sites directly.

1 hour ago, Adamw said:

Not quite sure I understand the point.

I guess I'm the opposite, I don't understand the point of it working the way it does now. It is probably useful for Alpha-N tuning like Electredge mentioned, I haven't got much experience with TPS as load. In saying that, every other ECU software I've looked at uses standard linear interpolation. An option for both would be neat, or an option in the settings to choose "axis scaled interpolation - yes/no".