Building array with custom function

Hello,

I am facing a problem with building an array using a custom function.

I would like to transfer a task from the main script file to the function file. I have such a piece of script:

StageMain=0;
TStart=10;
TEnd=500;
TStep=0.001;
Tmag=1;
.
.
.
DataInput = ones(length(StageMain),8);
Tarray = ones(1,length(StageMain));
.
.
.
T=TStart;
while T<TEnd
T=T+TStart*StageMain;
StageMain=StageMain+TMag;
DataInput(StageMain,1) = double(T);
Tarray(1, StageMain) = double(T);
end

its job is to build (actually update) two arrays DataInput and Tarray. Now I am trying to put this in function file which also will give me two updated arrays.

function [DataInput, Tarray]  = arraybuilder(TStart, TEnd, TStep, TMag, StageMain)
T=TStart;
while T<TEnd
T=T+TStep*StageMain;
StageMain=StageMain+TMag;
DataInput(StageMain,1) = double(T);
Tarray(1, StageMain) = double(T);
end

however, it only builds one vertical array that has double-length and the first part is filled with 0 and the second one with correct answers for DataInput

Thank you for any ideas.

[Roger J]

I made the following function:

function [DataInput, Tarray]  = arraybuilder(TStart, TEnd, TStep, TMag, StageMain)
T=TStart;
while T<TEnd
T=T+TStep*StageMain;
StageMain=StageMain+TMag;
DataInput(StageMain,1) = double(T);
Tarray(1, StageMain) = double(T);
end

and then called it from the commnad line with:

[X Y] = arraybuilder(10,500,.001,1,0)

and the answer shows that both X and Y are 991 non-zero elements, and X(i) == Y(i) for all i.

[Mateusz Brzezinski]

Ok thanks, but for this set

[X Y] = arraybuilder(3.372510000000000e+02,380,.001,1,0)

it makes no sense and in main file it does.

[Roger J]

when I run with

[X Y] = arraybuilder(3.372510000000000e+02,380,.001,1,0)

I get X and Y with 293 non-zero elements, and X(i) == Y(i) for all i.

I'm still not seeing the problem that you described.

[Mateusz Brzezinski]

Ok, that is just my stupidity, I was calling it using "pure" arraybuilder(3.372510000000000e+02,380,.001,1,0) and expecting to get two outputs. After calling it like you did it [X Y] it works like a charm.

Thank you.

[Roger J]

Good! We've all been there. Mark the answer accepted, if you can.

Answer 1

[Roger J]

If you don't assign the return values from a function call, then only the first is assigned to the default

ans

variable.