How to find value from vector

Hello,

After calculation gammadot that need locate in table_gammadot (I tried "ismember" is no help), so to get table_eta that function table_gammadot.

Do not use interp1!

Thanks for the helpers

function [eta]=Viscosityy(y)
L0=128; 
gammadot= y/(y-L0);
table_gammadot=[0.02 0.05 0.09 0.18 0.3 0.5 0.9 1.8 3 5 9 18 30]; 
%locate in table_gammadot that equal value to gammadot 
%table_gammadot=result
%table_eta is function table_gammadot
%for example table_gammadot=0.05 => table_eta=28.73309
table_eta=[62.20241 28.73309 16.96822 9.024566 5.742004 3.634656 2.099485 1.107372 0.703221 0.429745 0.251424 0.134518 0.082058];
%eta=table_eta   
end
end

[Mario Malic]

Hello,

Are you looking to return the table_eta value for a given table_gammadot without interpolation of table_eta values in between?

findVal = 0.18
eta = table_eta(findVal == table_gammadot)

[Emilia]

That's not what I meant. Yes without interpolation.

For example gammadot=0.03, from table_gammadot we get 0.05 => table_eta= 28.73309

eta=table_eta

[Mario Malic]

For gammadot=0.03, why shouldn't the table_gammadot be 0.02, since it's the closest one. Are you taking the next higher value?

[Emilia]

Sorry I was wrong. Yes you are right the table_gammadot be 0.02.

Answer 1

[Mario Malic]

This will do it

findVal = 0.03;
[~, valIndex] = min(abs(table_gammadot - findVal));
eta = table_eta(valIndex)

[Emilia]

Excellent, thank you very much!