Package ucar.ma2

Class MAMath

java.lang.Object
ucar.ma2.MAMath
public class MAMath extends Object
Element by element algebra on Arrays
See Also:

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Class
    Description
    static class 
    MAMath.MinMax
    Holds a minimum and maximum value.
    static class 
    MAMath.ScaleOffset
    Holds a scale and offset.

  • Constructor Summary

    Constructors
    Constructor
    Description
    MAMath()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    static Array
    add(Array a, Array b)
    Add elements of two arrays together, allocating the result array.
    static void
    addDouble(Array result, Array a, Array b)
    Add elements of two arrays together as doubles, place sum in the result array.
    static MAMath.ScaleOffset
    calcScaleOffsetSkipMissingData(Array a, double missingValue, int nbits)
    Calculate the scale/offset for an array of numbers.
    static boolean
    conformable(int[] shapeA, int[] shapeB)
    Check that two array shapes are conformable.
    static boolean
    conformable(Array a, Array b)
    Check that two arrays are conformable.
    static Array
    convert(Array org, DataType wantType)
    Convert original array to desired type
    static Array
    convert2packed(Array unpacked, double missingValue, int nbits, DataType packedType)
     
    static Array
    convert2Unpacked(Array packed, MAMath.ScaleOffset scaleOffset)
     
    static void
    copy(Array result, Array a)
    Copy array a to array result, the result array will be in canonical order The operation type is taken from the type of a.
    static void
    copy(DataType dataType, IndexIterator from, IndexIterator to)
    Copy using iterators.
    static void
    copyBoolean(Array result, Array a)
    copy array a to array result as bytes The array a and result must be type boolean
    static void
    copyByte(Array result, Array a)
    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).
    static void
    copyChar(Array result, Array a)
    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).
    static void
    copyDouble(Array result, Array a)
    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).
    static void
    copyFloat(Array result, Array a)
    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).
    static void
    copyInt(Array result, Array a)
    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).
    static void
    copyLong(Array result, Array a)
    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).
    static void
    copyObject(Array result, Array a)
    copy array a to array result as an Object The array a and result must be type object
    static void
    copyShort(Array result, Array a)
    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).
    static boolean
    equals(Array array1, Array array2)
    Returns true if the specified arrays have the same data type, shape, and equal corresponding elements.
    static double
    getMaximum(Array a)
     
    static double
    getMaximumSkipMissingData(Array a, double missingValue)
     
    static double
    getMinimum(Array a)
     
    static double
    getMinimumSkipMissingData(Array a, double missingValue)
     
    static MAMath.MinMax
    getMinMax(Array a)
    Find min and max value in this array, getting values as doubles.
    static MAMath.MinMax
    getMinMaxSkipMissingData(Array a, double missingValue)
     
    static MAMath.MinMax
    getMinMaxSkipMissingData(Array a, IsMissingEvaluator eval)
     
    static int
    hashCode(Array array)
    An implementation of Object.hashCode() that is consistent with equals(Array, Array).
    static boolean
    nearlyEquals(Array data1, Array data2)
    Returns true if the specified arrays have the same size, signedness, and approximately equal corresponding elements.
    static int
    reducedRank(int[] shape)
    Calculate the reduced rank of this shape, by subtracting dimensions with length 1
    static void
    setDouble(Array result, double val)
    Set all the elements of this array to the given double value.
    static double
    sumDouble(Array a)
    sum all of the elements of array a as doubles.
    static double
    sumDoubleSkipMissingData(Array a, double missingValue)
    sum all of the elements of array a as doubles.

    Methods inherited from class java.lang.Object

    equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

    • MAMath

      public MAMath()

  • Method Details

    • add

      public static Array add(Array a, Array b) throws IllegalArgumentException
      Add elements of two arrays together, allocating the result array. The result type and the operation type are taken from the type of a.
      Parameters:
      a - add values from here
      b - add values from here
      Returns:
      result = a + b
      Throws:
      IllegalArgumentException - a and b are not conformable
      UnsupportedOperationException - dont support this data type yet

    • 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

    • copy

      public static void copy(DataType dataType, IndexIterator from, IndexIterator to) throws IllegalArgumentException
      Copy using iterators. Will copy until !from.hasNext().
      Parameters:
      dataType - use this operation type (eg DataType.DOUBLE uses getDoubleNext())
      from - copy from here
      to - copy to here
      Throws:
      IllegalArgumentException - a and b are not conformable
      UnsupportedOperationException - dont support this data type

    • copy

      public static void copy(Array result, Array a) throws IllegalArgumentException
      Copy array a to array result, the result array will be in canonical order The operation type is taken from the type of a.
      Parameters:
      result - copy to here
      a - copy from here
      Throws:
      IllegalArgumentException - a and b are not conformable
      UnsupportedOperationException - dont support this data type yet

    • 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

    • getMinMaxSkipMissingData

      public static MAMath.MinMax getMinMaxSkipMissingData(Array a, IsMissingEvaluator eval)

    • 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)

    • convert2Unpacked

      public static Array convert2Unpacked(Array packed, MAMath.ScaleOffset scaleOffset)

    • 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:

    • 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.