Package ffx.numerics.multipole

Class MultipoleUtilities

java.lang.Object
ffx.numerics.multipole.MultipoleUtilities
public class MultipoleUtilities extends Object

  • Constructor Summary

    Constructors
    Constructor
    Description
    MultipoleUtilities()
     

  • Method Summary

    Modifier and Type
    Method
    Description
    protected static String
    lmn(int l, int m, int n)
    Convenience method for writing out tensor indices.
    protected static String
    loadTensor(int l, int n, int m, HashMap<Integer,String> tensorMap)
    Load a tensor element into a SIMD register.
    protected static String
    rlmn(int l, int m, int n)
    Convenience method for writing out tensor indices.
    protected static String
    storePotential(String to, int l, int n, int m)
    Code to store an electrostatic potential element into an array.
    protected static String
    storePotentialNeg(String to, int l, int n, int m)
    Code to store a negated electrostatic potential element into an array.
    static int
    tensorCount(int order)
    Returns the number of tensors for derivatives to the given order.
    protected static String
    term(int l, int m, int n)
    Convenience method for writing out intermediate terms in the recursion.
    protected static String
    term(int l, int m, int n, int j)
    Convenience method for writing out intermediate terms in the recursion.
    protected static int
    ti(int dx, int dy, int dz, int order)
    The index is based on the idea of filling tetrahedron.

    Methods inherited from class java.lang.Object

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

  • Constructor Details

    • MultipoleUtilities

      public MultipoleUtilities()

  • Method Details

    • tensorCount

      public static int tensorCount(int order)
      Returns the number of tensors for derivatives to the given order.
      Parameters:
      order - maximum number of derivatives.
      Returns:
      the number of tensors.
      Since:
      1.0

    • rlmn

      protected static String rlmn(int l, int m, int n)
      Convenience method for writing out tensor indices.
      Parameters:
      l - number of d/dx partial derivatives.
      m - number of d/dx partial derivatives.
      n - number of d/dx partial derivatives.
      Returns:
      a String of the form Rlmn.

    • term

      protected static String term(int l, int m, int n)
      Convenience method for writing out intermediate terms in the recursion.
      Parameters:
      l - number of d/dx partial derivatives.
      m - number of d/dx partial derivatives.
      n - number of d/dx partial derivatives.
      Returns:
      a String of the form termLMN.

    • term

      protected static String term(int l, int m, int n, int j)
      Convenience method for writing out intermediate terms in the recursion.
      Parameters:
      l - number of d/dx partial derivatives.
      m - number of d/dx partial derivatives.
      n - number of d/dx partial derivatives.
      j - the jth intermediate term.
      Returns:
      a String of the form termLMNJ.

    • ti

      protected static int ti(int dx, int dy, int dz, int order)
      The index is based on the idea of filling tetrahedron.

      1/r has an index of 0.
      derivatives of x are first; indices from 1..o for d/dx..(d/dx)^o
      derivatives of x and y are second; base triangle of size (o+1)(o+2)/2
      derivatives of x, y and z are last; total size (o+1)*(o+2)*(o+3)/6

      This function is useful to set up masking constants:
      static int Tlmn = ti(l,m,n,order)
      For example the (d/dy)^2 (1/R) storage location:
      static int T020 = ti(0,2,0,order)

      Parameters:
      dx - int The number of d/dx operations.
      dy - int The number of d/dy operations.
      dz - int The number of d/dz operations.
      order - int The maximum tensor order (0 .LE. dx + dy + dz .LE. order).
      Returns:
      int in the range (0..binomial(order + 3, 3) - 1)

    • lmn

      protected static String lmn(int l, int m, int n)
      Convenience method for writing out tensor indices.
      Parameters:
      l - number of d/dx partial derivatives.
      m - number of d/dx partial derivatives.
      n - number of d/dx partial derivatives.
      Returns:
      a String of the form lmn.

    • loadTensor

      protected static String loadTensor(int l, int n, int m, HashMap<Integer,String> tensorMap)
      Load a tensor element into a SIMD register.

      For l=m=n=0, the returned String is: DoubleVector t000 = fromArray(SPECIES, t, T000);

      Parameters:
      l - The number of d/dx operations.
      n - The number of d/dy operations.
      m - The number of d/dz operations.
      Returns:
      a String of the form DoubleVector t000 = fromArray(SPECIES, t, T000);

    • storePotential

      protected static String storePotential(String to, int l, int n, int m)
      Code to store an electrostatic potential element into an array.

      For l=m=n=0, the returned String is (including a preceding tab): term000.intoArray(to, T000);

      Parameters:
      to - variable name of the array to store into.
      l - number of d/dx partial derivatives.
      n - number of d/dy partial derivatives.
      m - number of d/dz partial derivatives.
      Returns:
      a String of the form term000.intoArray(to, T000);

    • storePotentialNeg

      protected static String storePotentialNeg(String to, int l, int n, int m)
      Code to store a negated electrostatic potential element into an array.

      For l=m=n=0, the returned String is (including a preceding tab): term000.neg().intoArray(to, T000);

      Parameters:
      to - variable name of the array to store into.
      l - number of d/dx partial derivatives.
      n - number of d/dy partial derivatives.
      m - number of d/dz partial derivatives.
      Returns:
      a String of the form term000.intoArray(to, T000);