Package ucar.ma2

Class MAMath

  • public class MAMath
extends Object
    Element by element algebra on Arrays
    See Also:
    Index

    • Constructor Detail

      • MAMath

        public MAMath()

    • Method Detail

      • addDouble

        public static void addDouble​(Array result,
                             Array a,
                             Array b)
                      throws IllegalArgumentException
        Add elements of two arrays together as doubles, place sum in the result array. The values from the arrays a and b are converted to double (if needed), and the sum is converted to the type of result (if needed).
        Parameters:
        result - result array
        a - operand
        b - operand
        Throws:
        IllegalArgumentException - a,b,and result are not conformable

      • conformable

        public static boolean conformable​(Array a,
                                  Array b)
        Check that two arrays are conformable.
        Parameters:
        a - operand
        b - operand
        Returns:
        true if conformable

      • conformable

        public static boolean conformable​(int[] shapeA,
                                  int[] shapeB)
        Check that two array shapes are conformable. The shapes must match exactly, except that dimensions of length 1 are ignored.
        Parameters:
        shapeA - shape of array 1
        shapeB - shape of array 2
        Returns:
        true if conformable

      • convert

        public static Array convert​(Array org,
                            DataType wantType)
        Convert original array to desired type
        Parameters:
        org - original array
        wantType - desired type
        Returns:
        converted data of desired type, or original array if it is already

      • copyDouble

        public static void copyDouble​(Array result,
                              Array a)
                       throws IllegalArgumentException
        copy array a to array result as doubles The values from the arrays a are converted to double (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyFloat

        public static void copyFloat​(Array result,
                             Array a)
                      throws IllegalArgumentException
        copy array a to array result as floats The values from the arrays a are converted to float (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyLong

        public static void copyLong​(Array result,
                            Array a)
                     throws IllegalArgumentException
        copy array a to array result as longs The values from the array a are converted to long (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyInt

        public static void copyInt​(Array result,
                           Array a)
                    throws IllegalArgumentException
        copy array a to array result as integers The values from the arrays a are converted to integer (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyShort

        public static void copyShort​(Array result,
                             Array a)
                      throws IllegalArgumentException
        copy array a to array result as shorts The values from the array a are converted to short (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyChar

        public static void copyChar​(Array result,
                            Array a)
                     throws IllegalArgumentException
        copy array a to array result as char The values from the array a are converted to char (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyByte

        public static void copyByte​(Array result,
                            Array a)
                     throws IllegalArgumentException
        copy array a to array result as bytes The values from the array a are converted to byte (if needed), and then converted to the type of result (if needed).
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyBoolean

        public static void copyBoolean​(Array result,
                               Array a)
                        throws IllegalArgumentException
        copy array a to array result as bytes The array a and result must be type boolean
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • copyObject

        public static void copyObject​(Array result,
                              Array a)
                       throws IllegalArgumentException
        copy array a to array result as an Object The array a and result must be type object
        Parameters:
        result - copy to here
        a - copy from here
        Throws:
        IllegalArgumentException - a and result are not conformable

      • reducedRank

        public static int reducedRank​(int[] shape)
        Calculate the reduced rank of this shape, by subtracting dimensions with length 1
        Parameters:
        shape - shape of the array
        Returns:
        rank without dimensions of length 1

      • getMinimum

        public static double getMinimum​(Array a)

      • getMaximum

        public static double getMaximum​(Array a)

      • getMinMax

        public static MAMath.MinMax getMinMax​(Array a)
        Find min and max value in this array, getting values as doubles. Skip Double.NaN.
        Parameters:
        a - the array.
        Returns:
        MinMax

      • getMinimumSkipMissingData

        public static double getMinimumSkipMissingData​(Array a,
                                               double missingValue)

      • getMaximumSkipMissingData

        public static double getMaximumSkipMissingData​(Array a,
                                               double missingValue)

      • getMinMaxSkipMissingData

        public static MAMath.MinMax getMinMaxSkipMissingData​(Array a,
                                                     double missingValue)

      • setDouble

        public static void setDouble​(Array result,
                             double val)
        Set all the elements of this array to the given double value. The value is converted to the element type of the array, if needed.
        Parameters:
        result - change this Array
        val - set all elements to this value

      • sumDouble

        public static double sumDouble​(Array a)
        sum all of the elements of array a as doubles. The values from the array a are converted to double (if needed).
        Parameters:
        a - read values from this Array
        Returns:
        sum of elements

      • sumDoubleSkipMissingData

        public static double sumDoubleSkipMissingData​(Array a,
                                              double missingValue)
        sum all of the elements of array a as doubles. The values from the array a are converted to double (if needed).
        Parameters:
        a - read values from this Array
        missingValue - skip values equal to this, or which are NaNs
        Returns:
        sum of elements

      • calcScaleOffsetSkipMissingData

        public static MAMath.ScaleOffset calcScaleOffsetSkipMissingData​(Array a,
                                                                double missingValue,
                                                                int nbits)
        Calculate the scale/offset for an array of numbers. 
         If signed:
   then
     max value unpacked = 2^(n-1) - 1 packed
     min value unpacked = -(2^(n-1) - 1) packed
   note that -2^(n-1) is unused, and a good place to map missing values
   by solving 2 eq in 2 unknowns, we get:
     scale = (max - min) / (2^n - 2)
     offset = (max + min) / 2
 If unsigned then
     max value unpacked = 2^n - 1 packed
     min value unpacked = 0 packed
   and:
     scale = (max - min) / (2^n - 1)
     offset = min
   One could modify this to allow a holder for missing values.
        Parameters:
        a - array to convert (not changed)
        missingValue - skip these
        nbits - map into this many bits
        Returns:
        ScaleOffset, calculated as above.

      • convert2packed

        public static Array convert2packed​(Array unpacked,
                                   double missingValue,
                                   int nbits,
                                   DataType packedType)

      • nearlyEquals

        public static boolean nearlyEquals​(Array data1,
                                   Array data2)
        Returns true if the specified arrays have the same size, signedness, and approximately equal corresponding elements. float elements must be within Misc.defaultMaxRelativeDiffFloat of each other, as determined by Misc.nearlyEquals(double, double, double). Similarly, double elements must be within Misc.defaultMaxRelativeDiffDouble of each other.

        equals(Array, Array) is an alternative to this method that requires that corresponding elements be exactly equal. It is suitable for use in Object.equals(java.lang.Object) implementations, whereas this method isn't.

        Parameters:
        data1 - one array to be tested for equality.
        data2 - the other array to be tested for equality.
        Returns:
        true if the specified arrays have the same size, signedness, and approximately equal corresponding elems.

      • equals

        public static boolean equals​(Array array1,
                             Array array2)
        Returns true if the specified arrays have the same data type, shape, and equal corresponding elements. This method is suitable for use in Object.equals(java.lang.Object) implementations.

        Note that floating-point elements must be exactly equal, not merely within some epsilon of each other. This is because it's impossible to write a strictly-conforming Object.equals(java.lang.Object) implementation when an epsilon is incorporated, due to the transitivity requirement.

        nearlyEquals(ucar.ma2.Array, ucar.ma2.Array) is an alternative to this method that returns true if the corresponding elements are "approximately" equal to each other.

        Parameters:
        array1 - one array to be tested for equality.
        array2 - the other array to be tested for equality.
        Returns:
        true if the specified arrays have the same data type, shape, and equal corresponding elements.
        See Also:
        Is there a way to get a hashcode of a float with epsilon? - Stack Overflow

      • hashCode

        public static int hashCode​(Array array)
        An implementation of Object.hashCode() that is consistent with equals(Array, Array).
        Parameters:
        array - an array to hash.
        Returns:
        a hash code value for the array.