Package Summary Overview Summary

### class:VectorMask [NONE]
- Type Parameters: `E` - the boxed version of `ETYPE`, the element type of a vector ## Value-based classes and identity operations `VectorMask`, along with `Vector`, is a value-based class. With `VectorMask`, identity-sensitive operations such as `==` may yield unpredictable results, or reduced performance. Oddly enough, `v.equals(w)` is likely to be faster than `v==w`, since `equals` is not an identity sensitive method. (Neither is `toString` nor `hashCode`.) Also, vector mask objects can be stored in locals and parameters and as `static final` constants, but storing them in other Java fields or in array elements, while semantically valid, may incur performance penalties. public abstract class VectorMask<E>extends jdk.internal.vm.vector.VectorSupport.VectorMask<E> A `VectorMask` represents an ordered immutable sequence of `boolean` values. A `VectorMask` and `Vector` of the same element type (`ETYPE`) and `shape` have the same number of lanes, and are therefore compatible (specifically, their `vector species` are compatible). Some vector operations accept (compatible) masks to control the selection and operation of lane elements of input vectors. The number of values in the sequence is referred to as the `VectorMask` `length`. The length also corresponds to the number of VectorMask lanes. The lane element at lane index `N` (from `0`, inclusive, to length, exclusive) corresponds to the `N + 1` 'th value in the sequence. A lane is said to be set if the lane element is `true`, otherwise a lane is said to be unset if the lane element is `false`. VectorMask declares a limited set of unary, binary and reduction operations. A lane-wise unary operation operates on one input mask and produces a result mask. For each lane of the input mask the lane element is operated on using the specified scalar unary operation and the boolean result is placed into the mask result at the same lane. The following pseudocode illustrates the behavior of this operation category:
       VectorMask<E> a = ...;
       boolean[] ar = new boolean[a.length()];
       for (int i = 0; i < a.length(); i++) {
           ar[i] = scalar_unary_op(a.laneIsSet(i));
       }
       VectorMask<E> r = VectorMask.fromArray(a.vectorSpecies(), ar, 0);
- A lane-wise binary operation operates on two input masks to produce a result mask. For each lane of the two input masks a and b, the corresponding lane elements from a and b are operated on using the specified scalar binary operation and the boolean result is placed into the mask result at the same lane. The following pseudocode illustrates the behavior of this operation category:
       VectorMask<E> a = ...;
       VectorMask<E> b = ...;
       boolean[] ar = new boolean[a.length()];
       for (int i = 0; i < a.length(); i++) {
           ar[i] = scalar_binary_op(a.laneIsSet(i), b.laneIsSet(i));
       }
       VectorMask<E> r = VectorMask.fromArray(a.vectorSpecies(), ar, 0);
- A cross-lane reduction operation accepts an input mask and produces a scalar result. For each lane of the input mask the lane element is operated on, together with a scalar accumulation value, using the specified scalar binary operation. The scalar result is the final value of the accumulator. The following pseudocode illustrates the behaviour of this operation category:
       Mask<E> a = ...;
       int acc = zero_for_scalar_binary_op;  // 0, or 1 for &
       for (int i = 0; i < a.length(); i++) {
            acc = scalar_binary_op(acc, a.laneIsSet(i) ? 1 : 0);  // & | +
       }
       return acc;  // maybe boolean (acc != 0)

### method:vectorSpecies() [NONE]
### vectorSpecies public abstract VectorSpecies<E> vectorSpecies() Returns the vector species to which this mask applies. This mask applies to vectors of the same species, and the same number of lanes. Returns: the vector species of this mask

### method:length() [NONE]
### length public final int length() Returns the number of mask lanes. This mask applies to vectors of the same number of lanes, and the same species. Returns: the number of mask lanes

### method:fromValues(jdk.incubator.vector.VectorSpecies,boolean...) [NONE]
### fromValues public static <E> VectorMask<E> fromValues​(VectorSpecies<E> species, boolean... bits) Returns a mask where each lane is set or unset according to given `boolean` values. For each mask lane, where `N` is the mask lane index, if the given `boolean` value at index `N` is `true` then the mask lane at index `N` is set, otherwise it is unset. The given species must have a number of lanes that is compatible with the given array. Type Parameters: `E` - the boxed element type Parameters: `species` - vector species for the desired mask `bits` - the given `boolean` values Returns: a mask where each lane is set or unset according to the given `boolean` value Throws: `IllegalArgumentException` - if `bits.length != species.length()` See Also: `fromLong(VectorSpecies, long)` , `fromArray(VectorSpecies, boolean[], int)`

### method:fromArray(jdk.incubator.vector.VectorSpecies,boolean[],int) [NONE]
### fromArray public static <E> VectorMask<E> fromArray​(VectorSpecies<E> species, boolean[] bits, int offset) Loads a mask from a `boolean` array starting at an offset. For each mask lane, where `N` is the mask lane index, if the array element at index `offset + N` is `true` then the mask lane at index `N` is set, otherwise it is unset. Type Parameters: `E` - the boxed element type Parameters: `species` - vector species for the desired mask `bits` - the `boolean` array `offset` - the offset into the array Returns: the mask loaded from the `boolean` array Throws: `IndexOutOfBoundsException` - if `offset < 0` , or `offset > bits.length - species.length()` See Also: `fromLong(VectorSpecies, long)` , `fromValues(VectorSpecies, boolean...)`

### method:fromLong(jdk.incubator.vector.VectorSpecies,long) [NONE]
### fromLong public static <E> VectorMask<E> fromLong​(VectorSpecies<E> species, long bits) Returns a mask where each lane is set or unset according to the bits in the given bitmask, starting with the least significant bit, and continuing up to the sign bit. For each mask lane, where `N` is the mask lane index, if the expression `(bits>>min(63,N))&1` is non-zero, then the mask lane at index `N` is set, otherwise it is unset. If the given species has fewer than 64 lanes, the high `64-VLENGTH` bits of the bit-mask are ignored. If the given species has more than 64 lanes, the sign bit is replicated into lane 64 and beyond. Type Parameters: `E` - the boxed element type Parameters: `species` - vector species for the desired mask `bits` - the given mask bits, as a 64-bit signed integer Returns: a mask where each lane is set or unset according to the bits in the given integer value See Also: `fromValues(VectorSpecies, boolean...)` , `fromArray(VectorSpecies, boolean[], int)`

### method:cast(jdk.incubator.vector.VectorSpecies) [NONE]
### cast public abstract <F> VectorMask<F> cast​(VectorSpecies<F> species) Converts this mask to a mask of the given species of element type `F`. The `species.length()` must be equal to the mask length. The various mask lane bits are unmodified. For each mask lane, where `N` is the lane index, if the mask lane at index `N` is set, then the mask lane at index `N` of the resulting mask is set, otherwise that mask lane is not set. Type Parameters: `F` - the boxed element type of the species Parameters: `species` - vector species for the desired mask Returns: a mask converted by shape and element type Throws: `IllegalArgumentException` - if this mask length and the species length differ

### method:toLong() [NONE]
### toLong public abstract long toLong() Returns the lane elements of this mask packed into a `long` value for at most the first 64 lane elements. The lane elements are packed in the order of least significant bit to most significant bit. For each mask lane where `N` is the mask lane index, if the mask lane is set then the `N`th bit is set to one in the resulting `long` value, otherwise the `N`th bit is set to zero. The mask must have no more than 64 lanes. Returns: the lane elements of this mask packed into a `long` value. Throws: `UnsupportedOperationException` - if there are more than 64 lanes in this mask

### method:toArray() [NONE]
### toArray public abstract boolean[] toArray() Returns an `boolean` array containing the lane elements of this mask. This method behaves as if it stores this mask into an allocated array (using `intoArray(boolean[], int)` ) and returns that array as follows:
     boolean[] a = new boolean[this.length()];
     this.intoArray(a, 0);
     return a;
Returns: an array containing the the lane elements of this vector

### method:intoArray(boolean[],int) [NONE]
### intoArray public abstract void intoArray​(boolean[] a, int offset) Stores this mask into a `boolean` array starting at offset. For each mask lane, where `N` is the mask lane index, the lane element at index `N` is stored into the array element `a[offset+N]`. Parameters: `a` - the array, of type boolean[] `offset` - the offset into the array Throws: `IndexOutOfBoundsException` - if `offset < 0` or `offset > a.length - this.length()`

### method:anyTrue() [NONE]
### anyTrue public abstract boolean anyTrue() Returns `true` if any of the mask lanes are set. Returns: `true` if any of the mask lanes are set, otherwise `false`.

### method:allTrue() [NONE]
### allTrue public abstract boolean allTrue() Returns `true` if all of the mask lanes are set. Returns: `true` if all of the mask lanes are set, otherwise `false`.

### method:trueCount() [NONE]
### trueCount public abstract int trueCount() Returns the number of mask lanes that are set. Returns: the number of mask lanes that are set.

### method:firstTrue() [NONE]
### firstTrue public abstract int firstTrue() Returns the index of the first mask lane that is set. Returns `VLENGTH` if none of them are set. Returns: the index of the first mask lane that is set, or `VLENGTH`

### method:lastTrue() [NONE]
### lastTrue public abstract int lastTrue() Returns the index of the last mask lane that is set. Returns `-1` if none of them are set. Returns: the index of the last mask lane that is set, or `-1`

### method:and(jdk.incubator.vector.VectorMask) [NONE]
### and public abstract VectorMask<E> and​(VectorMask<E> m) Computes the logical intersection (as `a&b`) between this mask and a second input mask. This is a lane-wise binary operation which applies the logical `AND` operation (`&`) to each corresponding pair of mask bits. Parameters: `m` - the second input mask Returns: the result of logically conjoining the two input masks

### method:or(jdk.incubator.vector.VectorMask) [NONE]
### or public abstract VectorMask<E> or​(VectorMask<E> m) Computes the logical union (as `a|b`) of this mask and a second input mask. This is a lane-wise binary operation which applies the logical `OR` operation (`|`) to each corresponding pair of mask bits. Parameters: `m` - the input mask Returns: the result of logically disjoining the two input masks

### method:eq(jdk.incubator.vector.VectorMask) [NONE]
### eq public abstract VectorMask<E> eq​(VectorMask<E> m) Determines logical equivalence of this mask to a second input mask (as boolean `a==b` or `a^~b`). This is a lane-wise binary operation tests each corresponding pair of mask bits for equality. It is also equivalent to a inverse `XOR` operation (`^~`) on the mask bits. Parameters: `m` - the input mask Returns: a mask showing where the two input masks were equal See Also: `equals(java.lang.Object)`

### method:andNot(jdk.incubator.vector.VectorMask) [NONE]
### andNot public abstract VectorMask<E> andNot​(VectorMask<E> m) Logically subtracts a second input mask from this mask (as `a&~b`). This is a lane-wise binary operation which applies the logical `ANDC` operation (`&~`) to each corresponding pair of mask bits. Parameters: `m` - the second input mask Returns: the result of logically subtracting the second mask from this mask

### method:not() [NONE]
### not public abstract VectorMask<E> not() Logically negates this mask. This is a lane-wise binary operation which applies the logical `NOT` operation (`~`) to each mask bit. Returns: the result of logically negating this mask

### method:indexInRange(int,int) [NONE]
### indexInRange public abstract VectorMask<E> indexInRange​(int offset, int limit) Removes lanes numbered `N` from this mask where the adjusted index `N+offset`, is not in the range `[0..limit-1]`. In all cases the series of set and unset lanes is assigned as if by using infinite precision or `VLENGTH-`saturating additions or subtractions, without overflow or wrap-around. API Note: This method performs a SIMD emulation of the check performed by `Objects.checkIndex(int,int)`, on the index numbers in the range `[offset..offset+VLENGTH-1]`. If an exception is desired, the resulting mask can be compared with the original mask; if they are not equal, then at least one lane was out of range, and exception processing can be performed. A mask which is a series of `N` set lanes followed by a series of unset lanes can be obtained by calling `allTrue.indexInRange(0, N)` , where `allTrue` is a mask of all true bits. A mask of `N1` unset lanes followed by `N2` set lanes can be obtained by calling `allTrue.indexInRange(-N1, N2)` . Parameters: `offset` - the starting index `limit` - the upper-bound (exclusive) of index range Returns: the original mask, with out-of-range lanes unset See Also: `VectorSpecies.indexInRange(int, int)`

### method:toVector() [NONE]
### toVector public abstract Vector<E> toVector() Returns a vector representation of this mask, the lane bits of which are set or unset in correspondence to the mask bits. For each mask lane, where `N` is the mask lane index, if the mask lane is set at `N` then the specific non-default value `-1` is placed into the resulting vector at lane index `N`. Otherwise the default element value `0` is placed into the resulting vector at lane index `N`. Whether the element type (`ETYPE`) of this mask is floating point or integral, the lane value, as selected by the mask, will be one of the two arithmetic values `0` or `-1`. For every `ETYPE` the most significant bit of the vector lane is set if and only if the mask lane is set. In addition, for integral types, all lane bits are set in lanes where the mask is set. The vector returned is the same as would be computed by `ZERO.blend(MINUS_ONE, this)` , where `ZERO` and `MINUS_ONE` are vectors which replicate the default `ETYPE` value and the `ETYPE` value representing `-1`, respectively. API Note: For the sake of static type checking, users may wish to check the resulting vector against the expected integral lane type or species. If the mask is for a float-point species, then the resulting vector will have the same shape and lane size, but an integral type. If the mask is for an integral species, the resulting vector will be of exactly that species. Returns: a vector representation of this mask See Also: `Vector.check(Class)`, `Vector.check(VectorSpecies)`

### method:laneIsSet(int) [NONE]
### laneIsSet public abstract boolean laneIsSet​(int i) Tests if the lane at index `i` is set Parameters: `i` - the lane index Returns: true if the lane at index `i` is set, otherwise false

### method:check(java.lang.Class) [NONE]
### check public abstract <F> VectorMask<F> check​(Class<F> elementType) Checks that this mask applies to vectors with the given element type, and returns this mask unchanged. The effect is similar to this pseudocode: `elementType == vectorSpecies().elementType() ? this : throw new ClassCastException()` . Type Parameters: `F` - the boxed element type of the required lane type Parameters: `elementType` - the required lane type Returns: the same mask Throws: `ClassCastException` - if the element type is wrong See Also: `Vector.check(Class)`, `check(VectorSpecies)`

### method:check(jdk.incubator.vector.VectorSpecies) [NONE]
### check public abstract <F> VectorMask<F> check​(VectorSpecies<F> species) Checks that this mask has the given species, and returns this mask unchanged. The effect is similar to this pseudocode: `species == vectorSpecies() ? this : throw new ClassCastException()` . Type Parameters: `F` - the boxed element type of the required species Parameters: `species` - vector species required for this mask Returns: the same mask Throws: `ClassCastException` - if the species is wrong See Also: `Vector.check(Class)`, `Vector.check(VectorSpecies)`

### method:toString() [NONE]
### toString public final String toString() Returns a string representation of this mask, of the form `"Mask[T.TT...]"`, reporting the mask bit settings (as 'T' or '.' characters) in lane order. Overrides: `toString` in class `Object` Returns: a string of the form `"Mask[T.TT...]"`

### method:equals(java.lang.Object) [NONE]
### equals public final boolean equals​(Object obj) Indicates whether this mask is identical to some other object. Two masks are identical only if they have the same species and same source indexes, in the same order. Overrides: `equals` in class `Object` Parameters: `obj` - the reference object with which to compare. Returns: whether this vector is identical to some other object See Also: `eq(jdk.incubator.vector.VectorMask<E>)`

### method:hashCode() [NONE]
### hashCode public final int hashCode() Returns a hash code value for the mask, based on the mask bit settings and the vector species. Overrides: `hashCode` in class `Object` Returns: a hash code value for this mask See Also: `Object.equals(java.lang.Object)`, `System.identityHashCode(java.lang.Object)`