How i can find the difference between 2 values.

I have 2 tables, with 1 column and 24 rows each.

I want to find the diferrence between each value in every row.

for example

T1=[1.5

2.5

3.5

4.5]

T2=[1.2

2

3

4]

The answer must be

Diff=[ 0.3

0.5

0.5

0.5]

Answer 1

[Jon]

y = T1 - T2

[Jon]

Note that there is a MATLAB function, called diff, although capitalized your variable named Diff, it would still help avoid confusion to use a different name for this variable.

Also, what you call "tables" are called matrices or arrays in MATLAB. A MATLAB table is for column oriented data and has additional features, like column names, row names etc. It's a little hard initially learning the terminology, but it is helpful to have the correct names for things to keep things clear.

[Jon]

In your comment to @Torsten you say that "i already did this but the answer is different".

I can not run the code you have attached as it requires other data and maybe functions that I don't have.

For any two column vectors, a and b, with an equal number of elements it is certain that the result of

delta = a - b

will be given by

delta = [a(1) - b(1);a(2) -b(2); ... a(i) - b(i); ... a(n) - b(n)];

If that isn't what you are getting then there must be some confusion about what is in your two vectors.

Please save your variables voltage1 and voltage to a .mat file and just attach the .mat file with these two variables using the paperclip.

[myrto pieridou]

Hello...thanks for the answer

here are the tables. You can see that the results are not correct!

voltage1=[1.0350;1.0350;0.9917;0.9997;1.0201;1.0154;1.0250;0.9947;1.0029;1.0308;0.9915;1.0052;1.0200;0.9800;1.0140;1.0170;1.0384;1.0500;1.0235;1.0387;1.0500;1.0500;1.0500;0.9790];
voltage=[1.0350;1.0350;0.9335;0.9907;1.0175;1.0112;1.0250;0.9899;0.9869;1.0247;0.9819;0.9941;1.0200;0.9800;1.0140;1.0170;1.0379;1.0500;1.0228;1.0385;1.0500;1.0500;1.0500;1.0169];
difference= voltage1 - voltage

difference = 24×1

0 0 0.0582 0.0090 0.0026 0.0042 0 0.0048 0.0160 0.0061

[Stephen23]

"You can see that the results are not correct!"

Please show us one specific value that is not correct.

Lets look for example at the third element:

voltage1 = [1.0350;1.0350;0.9917;0.9997;1.0201;1.0154;1.0250;0.9947;1.0029;1.0308;0.9915;1.0052;1.0200;0.9800;1.0140;1.0170;1.0384;1.0500;1.0235;1.0387;1.0500;1.0500;1.0500;0.9790];
voltage  = [1.0350;1.0350;0.9335;0.9907;1.0175;1.0112;1.0250;0.9899;0.9869;1.0247;0.9819;0.9941;1.0200;0.9800;1.0140;1.0170;1.0379;1.0500;1.0228;1.0385;1.0500;1.0500;1.0500;1.0169];
difference = voltage1 - voltage;
voltage(3)

ans = 0.9335

voltage1(3)

ans = 0.9917

voltage1(3) - voltage(3)

ans = 0.0582

difference(3)

ans = 0.0582

What value do you expect to get when you subtract 0.9335 from 0.9917 ?

[myrto pieridou]

for example in 14th, in my laptop when i runned the code in my laptop, the difference was -0.111, But it must be 0, because voltage1 and voltage are the same number.

[Stephen23]

"for example in 14th, in my laptop when i runned the code in my laptop, the difference was -0.111, But it must be 0, because voltage1 and voltage are the same number."

Then clearly they are not the same number on your laptop. Please save those arrays (exactly before the subtraction operation, not from anywhere else) in one MAT file and upload it here by clicking the paperclip button.

voltage1 = [1.0350;1.0350;0.9917;0.9997;1.0201;1.0154;1.0250;0.9947;1.0029;1.0308;0.9915;1.0052;1.0200;0.9800;1.0140;1.0170;1.0384;1.0500;1.0235;1.0387;1.0500;1.0500;1.0500;0.9790];
voltage  = [1.0350;1.0350;0.9335;0.9907;1.0175;1.0112;1.0250;0.9899;0.9869;1.0247;0.9819;0.9941;1.0200;0.9800;1.0140;1.0170;1.0379;1.0500;1.0228;1.0385;1.0500;1.0500;1.0500;1.0169];
difference = voltage1 - voltage;
voltage1(14)

ans = 0.9800

voltage(14)

ans = 0.9800

difference(14)

ans = 0

[myrto pieridou]

okayi will do this.Plese give me some time because i update my matlab now

[myrto pieridou]

I move the tables in other script, and the diffence now is correct. Maybe there is a missunderstanding in the code!

Thank yo for your help!

[Jon]

Glad you got this sorted out. If this answered your question please accept the answer. Thanks @Stephen23 for pressing through the details on this and helping the OP understand.

Answer 2

[Torsten]

T1=[1.5  
       2.5  
       3.5 
       4.5];
T2=[1.2  
       2   
       3  
        4];
Difference = T1 - T2

Difference = 4×1

0.3000 0.5000 0.5000 0.5000

[myrto pieridou]

i already did this but the answer is different. I will upload my code to see it.

clear all
define_constants;

Unrecognized function or variable 'define_constants'.

mpc=loadcase('case24_ieee_rts');

demand=[1775.835,1669.815,1590.3,1563.795,1563.795,1590.3,1961.37,2279.43,2517.975,2544.48,2544.48,2517.975,2517.975,2517.975,2464.965,2464.965,2623.995,2650.5,2650.5,2544.48,2411.955,2199.915,1934.865,1669.815]
time=[1:1:24];
voltage1=[1.0350;1.0350;0.9917;0.9997;1.0201;1.0154;1.0250;0.9947;1.0029;1.0308;0.9915;1.0052;1.0200;0.9800;1.0140;1.0170;1.0384;1.0500;1.0235;1.0387;1.0500;1.0500;1.0500;0.9790;];

%proportional load distribution
tot_load=0;
for i=1:1:24
    tot_load=tot_load+mpc.bus(i,PD);
end
load_prc=mpc.bus(:,PD)./tot_load;

for i=1:1:24 
mpc.bus(:,PD)=load_prc.*demand(i);


if i==19 
mpc.gen([3],BR_STATUS)=0; 
mpc.branch([3],BR_STATUS)=0; 

end

normal(i)=runpf(mpc)
end

voltage=normal(19).bus(:,VM)

Difference = voltage1 - voltage