org.das2.util.DasMath

DasMath( )

Creates a new instance of DasMath

biggerOf

biggerOf( double x1, double x2 ) → double

returns the bigger number of two numbers

Parameters

x1 - a number
x2 - a number

Returns:

the greater of the two numbers

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exp10

exp10( double x ) → double

Parameters

x - a double

Returns:

double

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exp10( int x ) → double

findex

findex( double[][] datax, double[][] x ) → double[]

Returns the "floating point indeces" of x within array datax. A floating point index (or "findex") indicates the indeces of the points that bracket and the weights of each bracketing point to use. A findex of 4.5 indicates that x is half-way between index 4 and 5, so equal weights should be used. floor( findex ) is the "left" bracket, ceil(findex) is the "right" bracket, and fp( findex ) is the weight for the right bracket. See interpolate for an example of its use.

Parameters

datax - a double[]
x - a double[]

Returns:

double[][]

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findex( double[][] datax, double x, int guess ) → double

gcd

gcd( double[][] A, double error ) → double

Returns the greatest common divisor of a group of numbers. This is useful for a number of visualization techniques, for instance when you need to integerize your data, the binsize should be the gcd. An error parameter is provided to avoid numerical noise, and in case there is a granularity that needn't be surpassed. org.das2.datum.DatumUtil has a private copy of this code.

Parameters

A - the array of numbers
error - the limit of the error to deal with numerical noise

Returns:

the greatest common divisor (GCD)

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interpolate

interpolate( double[][] datay, double findex ) → double

Interpolate just one point

Parameters

datay - a double[]
findex - a double

Returns:

double

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interpolate( double[][] datay, double[][] findex ) → double[]

log10

log10( double x ) → double

Parameters

x - a double

Returns:

double

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main

main( java.lang.String[][] args ) → void

Parameters

args - a java.lang.String[]

Returns:

void (returns nothing)

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max

max( double[][] A ) → double

return the maximum of the list

Parameters

A - the list of numbers

Returns:

the maximum of the list

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mean

mean( double[][] A ) → double

return the mean of the list. The first element's magnitude is removed from each accumulated value so that items with large offset values (for example times) can be averaged. There is no checking for NaNs or fill values.

Parameters

A - a double[]

Returns:

the mean of the list.

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median

median( double[][] A ) → double

return the median of the list length N, which is the value at index N/2 of the sorted list. This does not return the average for even-length lists. and there is no checking for NaNs or fill values.

Parameters

A - the list of numbers

Returns:

the median of the list

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min

min( double[][] A ) → double

return the minimum of the list

Parameters

A - the list

Returns:

the minimum of the list

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modp

modp( double x, double t ) → double

just like modulo (%) function, but negative numbers return positive phase.

Parameters

x - the numerator
t - the devisor

Returns:

the modulo, which will always be positive

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modp( int x, int t ) → int

roundNFractionalDigits

roundNFractionalDigits( double x, int n ) → double

round the decimal to the number of fractional decimal places. For example, DasMath.roundNFractionalDigits(1.2345678,3)==1.23 Note the name implies that there will be three decimals in the fractional part, but this implementation will return only two.

Parameters

x - a double
n - number of decimal places

Returns:

the number rounded to the number of decimal places.

See Also:

roundNSignificantDigits(double, int)
https://github.com/autoplot/dev/blob/master/demos/2023/20230910/roundNDigits.jy


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roundNSignificantDigits

roundNSignificantDigits( double x, int n ) → double

Round the double to n significant digits by removing the exponent to make the number order one, then rounding the mantissa, then replacing the exponent.

Parameters

x - a double
n - number of decimal places

Returns:

the number rounded to the number of decimal places.

See Also:

roundNFractionalDigits(double, int)
https://github.com/autoplot/dev/blob/master/demos/2023/20230910/roundNDigits.jy


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sort

sort( double[][] A ) → double[]

return a sorted version of the array. The original array is not modified.

Parameters

A - a double[]

Returns:

return a sorted version of the array.

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tanh

tanh( double x ) → double

Parameters

x - a double

Returns:

double

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