485 * @param <R> type of the result
486 * @param supplier a function that creates a new result container. For a
487 * parallel execution, this function may be called
488 * multiple times and must return a fresh value each time.
489 * @param accumulator an <a href="package-summary.html#Associativity">associative</a>
490 * <a href="package-summary.html#NonInterference">non-interfering,
491 * stateless</a> function for incorporating an additional
492 * element into a result
493 * @param combiner an <a href="package-summary.html#Associativity">associative</a>
494 * <a href="package-summary.html#NonInterference">non-interfering,
495 * stateless</a> function for combining two values, which
496 * must be compatible with the accumulator function
497 * @return the result of the reduction
498 * @see Stream#collect(Supplier, BiConsumer, BiConsumer)
499 */
500 <R> R collect(Supplier<R> supplier,
501 ObjDoubleConsumer<R> accumulator,
502 BiConsumer<R, R> combiner);
503
504 /**
505 * Returns the sum of elements in this stream. The sum returned can vary
506 * depending upon the order in which elements are encountered. This is due
507 * to accumulated rounding error in addition of values of differing
508 * magnitudes. Elements sorted by increasing absolute magnitude tend to
509 * yield more accurate results. If any stream element is a {@code NaN} or
510 * the sum is at any point a {@code NaN} then the sum will be {@code NaN}.
511 * This is a special case of a
512 * <a href="package-summary.html#Reduction">reduction</a> and is
513 * equivalent to:
514 * <pre>{@code
515 * return reduce(0, Double::sum);
516 * }</pre>
517 *
518 * <p>This is a <a href="package-summary.html#StreamOps">terminal
519 * operation</a>.
520 *
521 * @return the sum of elements in this stream
522 */
523 double sum();
524
525 /**
526 * Returns an {@code OptionalDouble} describing the minimum element of this
527 * stream, or an empty OptionalDouble if this stream is empty. The minimum
528 * element will be {@code Double.NaN} if any stream element was NaN. Unlike
529 * the numerical comparison operators, this method considers negative zero
530 * to be strictly smaller than positive zero. This is a special case of a
531 * <a href="package-summary.html#Reduction">reduction</a> and is
532 * equivalent to:
533 * <pre>{@code
534 * return reduce(Double::min);
535 * }</pre>
536 *
537 * <p>This is a <a href="package-summary.html#StreamOps">terminal
538 * operation</a>.
539 *
540 * @return an {@code OptionalDouble} containing the minimum element of this
561 * @return an {@code OptionalDouble} containing the maximum element of this
562 * stream, or an empty optional if the stream is empty
563 */
564 OptionalDouble max();
565
566 /**
567 * Returns the count of elements in this stream. This is a special case of
568 * a <a href="package-summary.html#Reduction">reduction</a> and is
569 * equivalent to:
570 * <pre>{@code
571 * return mapToLong(e -> 1L).sum();
572 * }</pre>
573 *
574 * <p>This is a <a href="package-summary.html#StreamOps">terminal operation</a>.
575 *
576 * @return the count of elements in this stream
577 */
578 long count();
579
580 /**
581 * Returns an {@code OptionalDouble} describing the arithmetic mean of elements of
582 * this stream, or an empty optional if this stream is empty. The average
583 * returned can vary depending upon the order in which elements are
584 * encountered. This is due to accumulated rounding error in addition of
585 * elements of differing magnitudes. Elements sorted by increasing absolute
586 * magnitude tend to yield more accurate results. If any recorded value is
587 * a {@code NaN} or the sum is at any point a {@code NaN} then the average
588 * will be {@code NaN}. This is a special case of a
589 * <a href="package-summary.html#Reduction">reduction</a>.
590 *
591 * <p>This is a <a href="package-summary.html#StreamOps">terminal
592 * operation</a>.
593 *
594 * @return an {@code OptionalDouble} containing the average element of this
595 * stream, or an empty optional if the stream is empty
596 */
597 OptionalDouble average();
598
599 /**
600 * Returns a {@code DoubleSummaryStatistics} describing various summary data
601 * about the elements of this stream. This is a special
602 * case of a <a href="package-summary.html#Reduction">reduction</a>.
603 *
604 * <p>This is a <a href="package-summary.html#StreamOps">terminal
605 * operation</a>.
606 *
607 * @return a {@code DoubleSummaryStatistics} describing various summary data
608 * about the elements of this stream
609 */
610 DoubleSummaryStatistics summaryStatistics();
611
612 /**
|
485 * @param <R> type of the result
486 * @param supplier a function that creates a new result container. For a
487 * parallel execution, this function may be called
488 * multiple times and must return a fresh value each time.
489 * @param accumulator an <a href="package-summary.html#Associativity">associative</a>
490 * <a href="package-summary.html#NonInterference">non-interfering,
491 * stateless</a> function for incorporating an additional
492 * element into a result
493 * @param combiner an <a href="package-summary.html#Associativity">associative</a>
494 * <a href="package-summary.html#NonInterference">non-interfering,
495 * stateless</a> function for combining two values, which
496 * must be compatible with the accumulator function
497 * @return the result of the reduction
498 * @see Stream#collect(Supplier, BiConsumer, BiConsumer)
499 */
500 <R> R collect(Supplier<R> supplier,
501 ObjDoubleConsumer<R> accumulator,
502 BiConsumer<R, R> combiner);
503
504 /**
505 * Returns the sum of elements in this stream.
506 *
507 * Summation is a special case of a <a
508 * href="package-summary.html#Reduction">reduction</a>. If
509 * floating-point summation were exact, this method would be
510 * equivalent to:
511 *
512 * <pre>{@code
513 * return reduce(0, Double::sum);
514 * }</pre>
515 *
516 * However, since floating-point summation is not exact, the above
517 * code is not necessarily equivalent to the summation computation
518 * done by this method.
519 *
520 * <p>If any stream element is a NaN or the sum is at any point a NaN
521 * then the sum will be NaN.
522 *
523 * The value of a floating-point sum is a function both
524 * of the input values as well as the order of addition
525 * operations. The order of addition operations of this method is
526 * intentionally not defined to allow for implementation
527 * flexibility to improve the speed and accuracy of the computed
528 * result.
529 *
530 * In particular, this method may be implemented using compensated
531 * summation or other technique to reduce the error bound in the
532 * numerical sum compared to a simple summation of {@code double}
533 * values.
534 *
535 * <p>This is a <a href="package-summary.html#StreamOps">terminal
536 * operation</a>.
537 *
538 * @apiNote Sorting values by increasing absolute magnitude tends to yield
539 * more accurate results.
540 *
541 * @return the sum of elements in this stream
542 */
543 double sum();
544
545 /**
546 * Returns an {@code OptionalDouble} describing the minimum element of this
547 * stream, or an empty OptionalDouble if this stream is empty. The minimum
548 * element will be {@code Double.NaN} if any stream element was NaN. Unlike
549 * the numerical comparison operators, this method considers negative zero
550 * to be strictly smaller than positive zero. This is a special case of a
551 * <a href="package-summary.html#Reduction">reduction</a> and is
552 * equivalent to:
553 * <pre>{@code
554 * return reduce(Double::min);
555 * }</pre>
556 *
557 * <p>This is a <a href="package-summary.html#StreamOps">terminal
558 * operation</a>.
559 *
560 * @return an {@code OptionalDouble} containing the minimum element of this
581 * @return an {@code OptionalDouble} containing the maximum element of this
582 * stream, or an empty optional if the stream is empty
583 */
584 OptionalDouble max();
585
586 /**
587 * Returns the count of elements in this stream. This is a special case of
588 * a <a href="package-summary.html#Reduction">reduction</a> and is
589 * equivalent to:
590 * <pre>{@code
591 * return mapToLong(e -> 1L).sum();
592 * }</pre>
593 *
594 * <p>This is a <a href="package-summary.html#StreamOps">terminal operation</a>.
595 *
596 * @return the count of elements in this stream
597 */
598 long count();
599
600 /**
601 * Returns an {@code OptionalDouble} describing the arithmetic
602 * mean of elements of this stream, or an empty optional if this
603 * stream is empty.
604 *
605 * If any recorded value is a NaN or the sum is at any point a NaN
606 * then the average will be NaN.
607 *
608 * <p>The average returned can vary depending upon the order in
609 * which values are recorded.
610 *
611 * This method may be implemented using compensated summation or
612 * other technique to reduce the error bound in the {@link #sum
613 * numerical sum} used to compute the average.
614 *
615 * <p>The average is a special case of a <a
616 * href="package-summary.html#Reduction">reduction</a>.
617 *
618 * <p>This is a <a href="package-summary.html#StreamOps">terminal
619 * operation</a>.
620 *
621 * @apiNote Elements sorted by increasing absolute magnitude tend
622 * to yield more accurate results.
623 *
624 * @return an {@code OptionalDouble} containing the average element of this
625 * stream, or an empty optional if the stream is empty
626 */
627 OptionalDouble average();
628
629 /**
630 * Returns a {@code DoubleSummaryStatistics} describing various summary data
631 * about the elements of this stream. This is a special
632 * case of a <a href="package-summary.html#Reduction">reduction</a>.
633 *
634 * <p>This is a <a href="package-summary.html#StreamOps">terminal
635 * operation</a>.
636 *
637 * @return a {@code DoubleSummaryStatistics} describing various summary data
638 * about the elements of this stream
639 */
640 DoubleSummaryStatistics summaryStatistics();
641
642 /**
|