Is that possible to Implement ๐ฟ๐ factorization without row pivoting ? can someone give me an example?

`lu(A,Val(false))`

I donโt want to use LinearAlgebra package , I want to implement the algorithm from scratch

Well, you can look at the source code for the `Pivot == false`

case. But if this is a learning exercise (or a homework problem), you might want to try to implement it yourself from a textbook description.

Than you .Can you tell me the name of textbook that can describe how to implement this code ?

If this really *is* a homework assignment, you should do some of the work yourself. As for LA resources, check out e.g. http://ulaff.net/.

I tried it like that :

```
using LinearAlgebra
using SparseArrays
function LU2(A::Union{Array{real},Array{Float64}})
n = size(A,1); # Assuming A is nxn.
U = copy(A);
L = eye(eltype(A),n);
for k=2:n
for i=k:n
L[i,k-1] = U[i,k-1]/U[k-1,k-1];
for j=k-1:n
U[i,j] = U[i,j] - L[i,k-1]*U[k-1,j];
end
end
end
return L,U
end
```

but the problem now is when I test it i got this error ( UndefVarError: eye not defined)

You can get the n \times n identity matrix using `Matrix{eltype(A)}(I,(n,n))`

.

I got UndefVarError: eltpe not defined

Sorry, typo. Fixed now.

thanks it works

Deleted code

You probably want `abs.(array)`

.

I did it like this

```
pivot = indmax(abs.(U[(k-1):n,k-1])) + k - 2;
```

but i got UndefVarError: indmax not defined

The function that used to be called.`indmax`

is now called `findmax`

.

Thanks.it works but i got different error

MethodError: no method matching +(::Tuple{Float64,Int64}, ::Int64)

Did you try running the `findmax`

function to see what kind of object it returns? And you can read the documentation of the function using `?findmax`

from the REPL.

Ah thereโs also `argmax`

.

Yes i did. it works but when I test it on a matrix I got this strange error

**( MethodError: no method matching +(::Tuple{Float64,Int64}, ::Int64) )**

I tried to figure out the problem in the code again but i didnโt note whatโs the problem

`findmax`

returns a tuple.

It is telling you that you are trying to add that tuple to an integer.