# Vec¶

## Description¶

A `Vec` is a composite type that defines a group of indexed signals (of any SpinalHDL basic type) under a single name.

## Declaration¶

The syntax to declare a vector is as follows:

Declaration

Description

Vec(type: Data, size: Int)

Create a vector capable of holding `size` elements of type `Data`

Vec(x, y, …)

Create a vector where indexes point to the provided elements.
This constructor supports mixed element width.

### Examples¶

```// Create a vector of 2 signed integers
val myVecOfSInt = Vec(SInt(8 bits), 2)
myVecOfSInt(0) := 2
myVecOfSInt(1) := myVecOfSInt(0) + 3

// Create a vector of 3 different type elements
val myVecOfMixedUInt = Vec(UInt(3 bits), UInt(5 bits), UInt(8 bits))

val x, y, z = UInt(8 bits)
val myVecOf_xyz_ref = Vec(x, y, z)

// Iterate on a vector
for(element <- myVecOf_xyz_ref) {
element := 0   // Assign x, y, z with the value 0
}

// Map on vector
myVecOfMixedUInt.map(_ := 0) // Assign all elements with value 0

// Assign 3 to the first element of the vector
myVecOf_xyz_ref(1) := 3
```

## Operators¶

The following operators are available for the `Vec` type:

### Comparison¶

Operator

Description

Return type

x === y

Equality

Bool

x =/= y

Inequality

Bool

```// Create a vector of 2 signed integers
val vec2 = Vec(SInt(8 bits), 2)
val vec1 = Vec(SInt(8 bits), 2)

myBool := vec2 === vec1  // Compare all elements
```

### Type cast¶

Operator

Description

Return

x.asBits

Binary cast to Bits

Bits(w(x) bits)

```// Create a vector of 2 signed integers
val vec1 = Vec(SInt(8 bits), 2)

myBits_16bits := vec1.asBits
```

### Misc¶

Operator

Description

Return

x.getBitsWidth

Return the full size of the Vec

Int

```// Create a vector of 2 signed integers
val vec1 = Vec(SInt(8 bits), 2)

println(vec1.getBitsWidth) // 16
```

### Lib helper functions¶

Note

You need to import `import spinal.lib._` to put these functions in scope.

Operator

Description

Return

x.sCount(condition: T => Bool)

Count the number of occurence matching a given condition in the Vec.

UInt

x.sCount(value: T)

Count the number of occurence of a value in the Vec.

UInt

x.sExists(condition: T => Bool)

Check if there is a matching condition in the Vec.

Bool

x.sContains(value: T)

Check if there is an element with a given value present in the Vec.

Bool

x.sFindFirst(condition: T => Bool)

Find the first element matching the given condition in the Vec, return the index of that element.

UInt

x.reduceBalancedTree(op: (T, T) => T)

Balanced reduce function, to try to minimize the depth of the resulting circuit. `op` should be commutative and associative.

T

x.shuffle(indexMapping: Int => Int)

Shuffle the Vec using a function that maps the old indexes to new ones.

Vec[T]

```import spinal.lib._

// Create a vector with 4 unsigned integers
val vec1 = Vec(UInt(8 bits), 4)

// ... the vector is actually assigned somewhere

val c1: UInt = vec1.sCount(_ < 128) // how many values are lower than 128 in vec
val c2: UInt = vec1.sCount(0) // how many values are equal to zero in vec

val b1: Bool = vec1.sExists(_ > 250) // is there a element bigger than 250
val b2: Bool = vec1.sContains(0) // is there a zero in vec

val u1: UInt = vec1.sFindFirst(_ < 10) // get the index of the first element lower than 10
val u2: UInt = vec1.reduceBalancedTree(_ + _) // sum all elements together
```

Note

The sXXX prefix is used to disambiguate with respect to identically named Scala functions that accept a lambda function as argument.