dsearchn() Command is slowing down my algorithm, Any better Solution? MATLAB

I am using the following code to calculate altitude.

Data = [Distance1',Gradient];

Result = Data(dsearchn(Data(:,1), Distance2), 2); 

Altitude = -cumtrapz(Distance2, Result)/1000;

Distance 1 and Distance 2 has different size with same values so I am comparing them to get corresponding value of Gradient to use with Distance 2.

Just to execute these 3 lines the Matlab takes 12 to 15 seconds. Which slow down my whole algorithm.

Is there any better way I can perform above action without slowing down my algorithm?

[Bruno Luong]

Yeah of course, almost anything else is better, why on earth are you using DSEARCHN for numbers? Use INTERP1 with 'nearest' option.

[Shahab Khan]

Can you please elaborate with an example in my case how should i use it?

[Bruno Luong]

Other way around: first you give us a (small) example.

[Shahab Khan]

I believe I already have given an example in my question about what i am trying to do.

[Bruno Luong]

You give a piece of code, without telling the size the class of your Data. No one can run your code if copy/past in MATLAB. Almost useless for people who tries to answer the question.

An "example" is some extra instruction to generate a small piece data, (and eventually an expecting output if the code is buggy and does not produce what you expect).

[Shahab Khan]

Apologies.

Here is my example.

Distance2= [1:10:1000]';
Distance1= [1:1:1000]';
Gradient= rand(1000,1);
Data= [Distance1,Gradient];
Result = Data(dsearchn(Data(:,1), Distance2), 2);

[Bruno Luong]

Replace

dsearchn(Data(:,1), Distance2)

by

interp1(Distance1,Distance2,'nearest');

[Shahab Khan]

This gives me distance values, I actually required gradient values from second column of Data corresponding to Distance1 in Data compared to Distance2 values.

For example, If Distance2 value is equal to Distance1 value in Data choose the corresponding value from second column in Data.

[Shahab Khan]

This command worked actually.

Result = interp1(Data(:,2),Distance2,'nearest');

Thank you for your help

[Bruno Luong]

I wrote replace just the DSEARCH, not the rest.

If you want to get the same Result as with

Data = [Distance1',Gradient];
Result = Data(dsearchn(Data(:,1), Distance2), 2);

and Data is just temporary variable and you don' mind to trash it away after, then

Result = interp1(Distance1,Gradient,Distance2,'nearest');

[Shahab Khan]

Thank you.

Answer 1

[Bruno Luong]

Replace

dsearchn(Data(:,1), Distance2)

by

interp1(Distance1,Distance2,'nearest');

If you want to get the same Result as with

Data = [Distance1',Gradient];
Result = Data(dsearchn(Data(:,1), Distance2), 2);

and Data is just temporary variable and you don' mind to trash it away after, then

Result = interp1(Distance1,Gradient,Distance2,'nearest');