Index exceeds the number of array elements (1)

Hello guys,

I have one error in the code "Index exceeds the number of array elements (1)" the code is

jay = [55 : 5 : 85] * 1000
temperature= [0.0002 : 0.0001 : 0.0003]
[n,m]=size(keyur);
for i=1:n
    X1=keyur(i,1); X2=keyur(i,2);
    X3=0.06;
    if X1<X3 && X2>X3
        disp([' Successful at ' num2str(jay(i)/1000) ' humidity and temperature ' num2str(temperature(i)*1000)])
    end
end

And the error is

Index exceeds the number of array elements (1).

Error in (line 8)

disp([' Successful at ' num2str(jay(i)/1000) ' humidity and temperature' num2str(temperature(i)*1000)])

Any idea to sort it out this error ? thanks ton

[Turlough Hughes]

You're trying to access the i'th element in temperature and jay with the index i. However, jay and certainly temperature (which is only a 1 by 3 array) don't have i elements. Hence you get the error: index exceeds the number of array elements.

Answer 1

[KSSV]

[n,m]=size(keyur);
jay = linspace(55,85,n)*1000
temperature= linspace(0.0002,0.0003,n) ;

for i=1:n
    X1=keyur(i,1); X2=keyur(i,2);
    X3=0.06;
    if X1<X3 && X2>X3
        disp([' Successful at ' num2str(jay(i)/1000) ' humidity and temperature ' num2str(temperature(i)*1000)])
    end
end

[Esila Darci]

@KSSV thanks but it still shows the same error

[KSSV]

Edited the answer.

[Esila Darci]

What if i don't want to use linespace because i would like to give them set of specific value by putting this condition [min value incremental rate max value] then

sorry but size of keyur value is calculated by at respective jay and temperature value, thats what i used keyur value it into condition.

For exmple

keyur (at jay 55 and temp 0.0002) =

X1 X2

0.00455632639600613 0.0881331282510282

5.45813345811941e-07 0.124865583837929

keyur (at jay 55 and temp 0.0003) =

X1 X2

0.00555632639600613 0.0251331282510282

2.45813345811941e-07 0.134865583837929

keyur (at jay 60 and temp 0.0002) =

X1 X2

0.00456632639600613 0.0681331282510282

2.45813345811941e-07 0.324865583837929

and so on different keyur value according to jay and temperature ...............

Thanks

Answer 2

[Walter Roberson]

format long g
jay = [55 : 5 : 85] * 1000

jay = 1×7

55000 60000 65000 70000 75000 80000 85000

temperature= [0.0002 : 0.0001 : 0.0003]

temperature = 1×2

1.0e+00 * 0.0002 0.0003

Your jay will definitely have more than one value. However, depending exactly how you calculated the bounds for temperature, temperature might end up with only a single element. You are hoping that 0.0002 + 0.0001 <= 0.0003 but that is not certain in MATLAB:

.1 + .2 - .3

ans = 
      5.55111512312578e-17

Notice this is not exactly 0. You have round-off going on, because 1/10^N is not exactly representable in IEEE 754 double precision for any positive integer N. -- not 1/100, not 1/1000 and so on. Sometimes the round-off falls the way you would like, but sometimes it doesn't. Depending exactly how you calculated the 0.0002 and 0.0003 they might have ended up slightly less than 0.0001 apart and so temperature might have been just the starting value.

[n,m]=size(keyur);
for i=1:n

fundamental problem there: the size of keyur is not related to the size of jay or the size of temperature, but you assume that you can index both according to the number of rows in keyur .

[Esila Darci]

@Walter Roberson , sorry but size of keyur value is calculated by at respective jay and temperature value, thats what i used keyur value it into condition.

For exmple

keyur (at jay 55, and temp 0.0002) =

X1 X2

0.00455632639600613 0.0881331282510282

5.45813345811941e-07 0.124865583837929

keyur (at jay 55, and temp 0.0003) =

X1 X2

0.00555632639600613 0.0251331282510282

2.45813345811941e-07 0.134865583837929

keyur (at jay 60, and temp 0.0002) =

X1 X2

0.00456632639600613 0.0681331282510282

2.45813345811941e-07 0.324865583837929

and so on different keyur value according to jay and temperature .....................

But i did not understand the what exactly you wanted to address me. Can you please tell me in code , so i can check it works or not ?

Thanks

[Walter Roberson]

You currently have

[n,m]=size(keyur);

outside of the loops, so the value and size of keyur does not depend upon the values of jay or temperature . Your keyur is constant relative to jay and temperature

My guess as to what you are really trying to do is

jay = [55 : 5 : 85] * 1000;
temperature= [0.0002 : 0.0001 : 0.0003];
num_jay = length(jay);
num_temperature = length(temperature);
X3 = 0.06;

for i = 1 : num_jay
    this_jay = jay(i);
    for k = 1 : num_temperature
        this_temperature = temperature(k);
        keyur = SomeFunctionCall(this_jay, this_temperature);
        X1 = keyur(1,1); X2 = keyur(1,2);
        if X1<X3 && X2>X3
            disp([' Successful at ' num2str(this_jay/1000) ' humidity and temperature ' num2str(this_temperature*1000)])
        end
    end
end

[Esila Darci]

I tried with this but again it shows the error

Unrecognized function or variable 'SomeFunctionCall'.

[Walter Roberson]

You would replace SomeFunctionCall with a call to a function that calculated keyur given a particular jay and temperature value, since you show in https://www.mathworks.com/matlabcentral/answers/1646155-index-exceeds-the-number-of-array-elements-1#comment_1976590 that keyur depends on the value of jay and temperature .

[Esila Darci]

Keyur is the function that calcualte the keyur at different jay and temp value.

so i replaced the somfunctioncall with keyur but shown me the error

Index in position 1 exceeds array bounds (must not exceed 4).

Error in line keyur = keyur(this_jay, this_temperature);

[Image Analyst]

You should then replace

keyur = keyur(this_jay, this_temperature);

with

keyur = Keyur(this_jay, this_temperature);

however I think it's bad practice to call your returned variable almost the same name as your function, despite the fact that MATLAB is case sensitive and Keyur is different than keyur. When you use keyur instead of Keyur, you're telling it you want the this_jay'th row and this_temperature'th column of the array keyur instead of telling it to pass those two values into the Keyur() function.

I recommend you either use a different name for keyur, like computedKeyur, or use a different name for your Keyur() function, like ComputeKeyur(), to avoid future confusion.

[Walter Roberson]

I agree with Image Analyst that it is best to use a variable name that is obviously different than the function name.

I personally have been known to use upper case and lower case variables that are otherwise the same; in particular I personally tend towards the practice of using lower case to represent vectors of values and upper case to represent grids of values (output from meshgrid() or ndgrid()) .

However, I mess up sometimes myself, and it can be difficult to catch. And I have certainly seen a number of times when other people have messed up when using different variables with only upper / lower distinction... and a lot of those times, it can be difficult to repair. People writing code tend to get confused between an entire array, and a variable representing a "current" value being paid attention to out of the array. When that happens they tend to write code that assumes that somehow at each point the "current" value is being updated as needed... often with different intended "current" values at different points in the same expression. Using obviously different variable names helps to focus the attention of the programmer to not confuse the individual element with the whole array.