Compute a geomtric series with matrices

[brad sue]

Hi ,
I want to compute a geomtric series with matrices. I have the following functions:

add (matrix1,matix2)=function to add 2 matrices.
mult(matirx1,matrix2) =function to multiply two matrices.

I want to create this function in C that computes the following.

I(indentity matrix)

I+A+A^2+A^3+...A^k

I tried

sum=I;
for(i=0;i<k;i++)
{
intermediary=mult(I,A);
sum+=intermediary;
intermediary=mult(intermediary,A)
}

Am I right?
Please, What is wrong here?

Thank you for yout help
B

 

[TenaliRaman]

//This should have been the code
sum=I;
intermediary = I;
for(i=0;i<k;i++)
{
intermediary=mult(intermediary,A)
sum+=intermediary;
}

Now what was wrong in your code?
sum=I;
for(i=0;i<k;i++)
{
intermediary=mult(I,A);[/Color] <---- Look at this, intermediary is set to IxA everytime here
sum+=intermediary;
intermediary=mult(intermediary,A)
}

-- AI

 

[brad sue]

//This should have been the code
sum=I;
intermediary = I;
for(i=0;i<k;i++)
{
intermediary=mult(intermediary,A)
sum+=intermediary;
}

Now what was wrong in your code?
sum=I;
for(i=0;i<k;i++)
{
intermediary=mult(I,A);[/Color] <---- Look at this, intermediary is set to IxA everytime here
sum+=intermediary;
intermediary=mult(intermediary,A)
}

-- AI

Yes !I see now what I have done wrong.
thanks a lot.