Can anyone explain why I have following warning and how to fix it?

I cannot see why I have problems. It seems the final answer is correct.

```
#Creating variance and covariance matrix
c <- diag(0.5, nrow = 4)
c[lower.tri(c)] <- c(0.2, -0.3, 0.2, 0.5, -0.4, -0.7)
d <- c + t(c)
e <- c(10, 12, 5, 18)
f<- outer(e, e) * d
f
#Defining expected return
mu7 <- c(10, -15, -15, 13)
#Define the value of lambda
labmda7 <- 0.8
#Define the benchmark portfolio weight
b7 <- c(0.2, 0.3, 0.4, 0.1)
#Solving alpha7
i <- c(1, 1, 1, 1)
alpha <- ( t(i) %*% solve(f) %*% mu7) / (t(i) %*% solve(f) %*% i)
xstar7 <- (1 / labmda7) * solve(f) %*% (mu7 - alpha * i )
warning:
Warning in alpha * i :
Recycling array of length 1 in array-vector arithmetic is deprecated.
Use c() or as.vector() instead.
```

**Note: Don't override R functions, like c. I renamed them for you.**

You need to convert the arrays to vectors using `as.vector`

.

```
x <- diag(0.5, nrow = 4) x[lower.tri(x)] <- c(0.2, -0.3, 0.2, 0.5, -0.4, -0.7) d <- x + t(x) e <- c(10, 12, 5, 18) f<- outer(e, e) * d f
#Defining expected return
mu7 <- c(10, -15, -15, 13) #Define the value of lambda
labmda7 <- 0.8 #Define the benchmark portfolio weight
b7 <- c(0.2, 0.3, 0.4, 0.1) #Solving alpha7
i <- c(1, 1, 1, 1)
alpha <- ( t(i) %*% solve(f) %*% mu7) / (t(i) %*% solve(f) %*% i)
alpha <- as.vector(alpha)
xstar7 <- (1 / labmda7) * solve(f) %*% (mu7 - alpha * i )
```

Or replace the last two lines with:

```
xstar7 <- (1 / labmda7) * solve(f) %*% (mu7 - as.vector(alpha) * i )
```

As you can see I write `i <- as.vector(i)`

also `alpha <- as.vector(alpha)`

.

And now the output has no warning, output:

```
[,1] [,2] [,3] [,4]
[1,] 100 24.0 -15 36.0
[2,] 24 144.0 30 -86.4
[3,] -15 30.0 25 -63.0
[4,] 36 -86.4 -63 324.0
```

**
Admin
| 3 weeks ago
**

This warning is given because `alpha`

is a matrix in your last line.

```
xstar7 <- (1 / labmda7) * solve(f) %*% (mu7 - as.vector(alpha) * i )
```

If you transform in a vector it will not an error.

**
Admin
| 3 weeks ago
**

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Original Link :
https://stackoverflow.com/questions/69331663