## ellipse

ellipse( double xwidth, double ywidth ) → QDataSet

return a dataset with X and Y forming a ellipse, introduced as a convenient way to indicate planet location of any planet, according to Masafumi.

### Parameters

xwidth - a double
ywidth - a double

### Returns:

QDataSet that when plotted is an ellipse.
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## ensureMonotonic

ensureMonotonic( QDataSet ds ) → QDataSet

possibly sort the data where the DEPEND_0 tags are monotonically increasing. If the data is already monotonic, then nothing is done to the data.

### Parameters

ds - the dataset

### Returns:

the dataset, sorted if necessary.

### See Also:

DataSetUtil#isMonotonic
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## ensureMonotonicAndIncreasingWithFill

ensureMonotonicAndIncreasingWithFill( QDataSet ds ) → QDataSet

Return data where the DEPEND_0 tags are monotonically increasing and non repeating. Instead of sorting the data, simply replace repeat records with a fill record.

### Parameters

ds - the dataset

### Returns:

the dataset, sorted if necessary. TODO: It's surprising that monotonic doesn't imply non-repeating, and this really needs to be revisited.

### See Also:

DataSetUtil#isMonotonicAndIncreasingQuick
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## eq

eq( QDataSet ds1, QDataSet ds2 ) → QDataSet

element-wise equality test. 1.0 is returned where the two datasets are equal. Fill is returned where either measurement is invalid.

### Parameters

ds1 - rank n dataset
ds2 - rank m dataset with compatible geometry.

### Returns:

rank n or m dataset.
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## eq

eq( Object ds1, Object ds2 ) → QDataSet

element-wise equality test, converting arguments as necessary to like units. These datasets can be nominal data as well.

### Parameters

ds1 - an Object
ds2 - an Object

### Returns:

a QDataSet
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## equalProperties

equalProperties( java.util.Map m1, java.util.Map m2 ) → java.util.HashMap

returns the subset of two groups of properties that are equal, so these may be preserved through operations.

### Parameters

m1 - map of dataset properties, including DEPEND properties.
m2 - map of dataset properties, including DEPEND properties.

### Returns:

the subset of two groups of properties that are equal
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## equivalent

equivalent( QDataSet ds1, QDataSet ds2 ) → boolean

returns true iff the dataset values are equivalent. Note this may promote rank, etc. If the two datasets have enumerations, then we create datums and check .equals. This does not check TITLE, etc, just that the units and values are equal.

### Parameters

ds1 - the first dataset
ds2 - the second dataset

### Returns:

true if the dataset values are equivalent.
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equivalent( Object ds1, Object ds2 ) → boolean [view source]

## eventsComplement

eventsComplement( QDataSet events, DatumRange range, int color, String msg ) → QDataSet

Return an events list of time intervals which are not covered in the events list. A new events list is returned, containing events with the given color and message. This is expected to have a number of uses, one being identifying where data is missing. Note this assumes events are not overlapping.

### Parameters

events - an events list
range - find gaps in events within this range
color - color for the missing events
msg - message to attach to these events

### Returns:

the events data set.

### See Also:

createEvent(java.lang.String, int, java.lang.String)
eventsConjunction(QDataSet, QDataSet)
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## eventsConjunction

eventsConjunction( QDataSet tE, QDataSet tB ) → QDataSet

return an events list of when events are found in both events lists. (This might have been better called "eventsIntersection")

### Parameters

tE - rank 2 canonical events list
tB - rank 2 canonical events list

### Returns:

rank 2 canonical events list

### See Also:

Schemes#eventsList()
dataIntersection(QDataSet, QDataSet)
eventsComplement(QDataSet, org.das2.datum.DatumRange, int, java.lang.String)
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## exp

exp( QDataSet ds ) → QDataSet

element-wise exponentiate e**x.

### Parameters

ds - the dataset

### Returns:

dataset of the same geometry
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## exp

exp( double d ) → double

Jython requires this be implemented

### Parameters

d - a double

### Returns:

e**d
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## exp

exp( Object ds1 ) → QDataSet

convert array, list, double, etc to QDataSet and return exp(d)

### Parameters

ds1 - requires this be implemented

### Returns:

exp(ds1)
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## exp10

exp10( QDataSet ds ) → QDataSet

element-wise exponentiate 10**x.

### Parameters

ds - a QDataSet

### Returns:

a QDataSet
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exp10( double ds1 ) → double [view source]
exp10( Object ds1 ) → QDataSet [view source]

## expandToFillGaps

expandToFillGaps( QDataSet ds ) → QDataSet

### Parameters

ds - a QDataSet

### Returns:

org.das2.qds.QDataSet
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## expandToFillGaps

expandToFillGaps( QDataSet ds, double factor ) → QDataSet

Special function by the RPW Group at U. Iowa, which reassigns timetags so the small waveform packets are visible, or bursty spectrograms are more easily viewed.

### Parameters

ds - a QDataSet
factor - duty cycle factor (0.5=50% duty cycle)

### Returns:

a QDataSet

### See Also:

expandWaveform(QDataSet)
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## expandWaveform

expandWaveform( QDataSet ds ) → QDataSet

special function needed by the RPW Group at U. Iowa, which reassigns timetags so the small waveform packets are visible.

### Parameters

ds - rank 2 waveform

### Returns:

a QDataSet

### See Also:

Schemes#rank2Waveform()
expandToFillGaps(QDataSet)
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## expm1

expm1( QDataSet ds ) → QDataSet

Returns ex -1. Note that for values of x near 0, the exact sum of `expm1(x)` + 1 is much closer to the true result of ex than `exp(x)`.

### Parameters

ds - a QDataSet

### Returns:

a QDataSet
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expm1( double ds ) → double [view source]
expm1( Object ds ) → QDataSet [view source]

## extent

extent( QDataSet ds ) → QDataSet

returns a two element, rank 1 dataset containing the extent of the data. Note this accounts for DELTA_PLUS, DELTA_MINUS properties. Note this accounts for BIN_PLUS, BIN_MINUS properties. The property QDataSet.SCALE_TYPE is set to lin or log. The property count is set to the number of valid measurements. TODO: this could use MONOTONIC, but it doesn't. DELTA_PLUS, DELTA_MINUS make that more difficult.

### Parameters

ds - the dataset to measure the extent

### Returns:

two element, rank 1 "bins" dataset.

### See Also:

DataSetUtil#rangeOfMonotonic(QDataSet)
AutoRangeUtil#simpleRange in Autoplot.
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## extent

extent( QDataSet ds, QDataSet range ) → QDataSet

returns a two element, rank 1 dataset containing the extent (min to max) of the data. Note this accounts for DELTA_PLUS, DELTA_MINUS properties. Note this accounts for BIN_PLUS, BIN_MINUS properties. If no valid data is found then [fill,fill] is returned. The property QDataSet.SCALE_TYPE is set to lin or log. The property count is set to the number of valid measurements. 2010-10-14: add branch for monotonic datasets.

### Parameters

ds - the dataset to measure the extent
range - if non-null, return the union of this range and the extent. This must not contain fill!

### Returns:

two element, rank 1 "bins" dataset.
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## extent

extent( QDataSet ds, QDataSet wds, QDataSet range ) → QDataSet

returns a two element, rank 1 dataset containing the extent (min to max) of the data, allowing an external evaluation of the weightsDataSet. If no valid data is found then [fill,fill] is returned.

### Parameters

ds - the dataset to measure the extent rank 1 or rank 2 bins
wds - a weights dataset, containing zero where the data is not valid, positive non-zero otherwise. If null, then all finite data is treated as valid.
range - if non-null, return the union of this range and the extent. This must not contain fill!

### Returns:

two element, rank 1 "bins" dataset.
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## extent445

extent445( QDataSet ds ) → QDataSet

### Parameters

ds - a QDataSet

### Returns:

org.das2.qds.QDataSet
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## extentSimple

extentSimple( QDataSet ds, QDataSet wds, QDataSet range ) → QDataSet

like extent, but does not account for DELTA_PLUS, DELTA_MINUS, BIN_PLUS, BIN_MINUS, BIN_MIN or BIN_MAX properties. This was introduced to provide a fast way to identify constant datasets and the extent that non-constant datasets vary.

### Parameters

ds - the dataset to measure the extent rank 1 or rank 2 bins
wds - a weights dataset, containing zero where the data is not valid, positive non-zero otherwise. If null, then all finite data is treated as valid.
range - if non-null, return the union of this range and the extent. This must not contain fill!

### Returns:

two element, rank 1 "bins" dataset.

### See Also:

extent(QDataSet, QDataSet, QDataSet)
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## extentSimple

extentSimple( QDataSet ds, QDataSet range ) → QDataSet

This is introduced to study effect of https://sourceforge.net/p/autoplot/feature-requests/445/ Do not use this in scripts!!! This is very interesting: Ops.extent: 53ms simpleRange: 77ms study445FastRange: 4ms Ops.extent: 76ms simpleRange: 114ms study445FastRange: 12ms This is likely showing that DataSetIterator is slow...

### Parameters

ds - the dataset
range - null, or rank 1 bins dataset

### Returns:

rank 1, two-element range, or when all data is fill result[0] will be Double.POSITIVE_INFINITY.

### See Also:

extentSimple(QDataSet, QDataSet, QDataSet)
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